Valcyte: Indications, Dosage, Precautions, Adverse Effects
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Valcyte - Product Information

Manufacture: Roche
Country: Australia
Condition: Cytomegalovirus Infection, CMV Retinitis
Class: Purine nucleosides
Form: Tablets
Ingredients: valganciclovir, microcrystalline cellulose (460), povidone K-30, crospovidone, stearic acid (570), hypromellose, titanium dioxide (171), macrogol 400, polysorbate 80 (433), red iron oxide (172)

Valganciclovir hydrochloride


CAS: 175865-59-5

The chemical name for valganciclovir hydrochloride is L-valine, 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]-3-hydroxypropyl ester, monohydrochloride. The molecular formula is C14H22N6O5 HCl and molecular weight is 390.83.

Description

Valganciclovir hydrochloride (valganciclovir HCl) is the hydrochloride salt of the L-valyl ester of ganciclovir. Ganciclovir is a synthetic nucleoside analogue of guanine.

Valganciclovir HCl is a white to off-white crystalline powder.

Valganciclovir HCl is a polar hydrophilic compound with a solubility of 70 mg/mL in water at 25°C at a pH of 7.0 and an n-octanol/water partition coefficient of 0.0095 at pH 7.0. The pKa for valganciclovir is 7.6.

VALCYTE is available as a 450 mg tablet for oral administration. Each tablet contains 496.3 mg valganciclovir HCl (corresponding to 450 mg valganciclovir), and inactive ingredients: microcrystalline cellulose, povidone K-30, crospovidone, and stearic acid. The film-coat applied to the tablets contains Opadry Pink which consists of hypromellose, titanium dioxide, macrogol 400, polysorbate 80 and red iron oxide.

VALCYTE is also available as a white to slightly yellow powder that is reconstituted to form an oral solution, containing 55 mg valganciclovir HCl per mL (equivalent to 50 mg valganciclovir). The inactive ingredients are: povidone K-30, fumaric acid, sodium benzoate (E211), saccharin sodium, mannitol and tutti-frutti flavour.

Pharmacology

Mechanism of Action

Valganciclovir is an L-valyl ester salt (prodrug) of ganciclovir which, after oral administration, is rapidly converted to ganciclovir by intestinal and hepatic esterases. Ganciclovir is a synthetic analogue of 2'-deoxyguanosine, which inhibits replication of herpes viruses in vitro and in vivo. Sensitive human viruses include human cytomegalovirus (HCMV), herpes-simplex virus-1 and -2 (HSV-1 and HSV-2), human herpes virus type 6, 7 and 8 (HHV-6, HHV-7, HHV-8), Epstein-Barr virus (EBV), varicella-zoster virus (VZV) and hepatitis B virus.

In cytomegalovirus (CMV)-infected cells, ganciclovir is initially phosphorylated to ganciclovir monophosphate by the viral protein kinase, UL97. Further phosphorylation occurs by cellular kinases to produce ganciclovir triphosphate, which is then slowly metabolised intracellularly. This has been shown to occur in CMV-infected cells (half-life 18 hours) and HSV-infected cells (half-life between 6 and 24 hours) after removal of extracellular ganciclovir. As the phosphorylation is largely dependent on the viral kinase, phosphorylation of ganciclovir occurs preferentially in virus-infected cells.

The virustatic activity of ganciclovir is due to inhibition of viral DNA synthesis by: (a) competitive inhibition of incorporation of deoxyguanosine-triphosphate into DNA by viral DNA polymerase, and (b) incorporation of ganciclovir triphosphate into viral DNA causing termination of, or very limited, further viral DNA elongation. Typical anti-viral IC50 against CMV in vitro is in the range 0.08 μM (0.02 μg/mL) to 14.32 μM (3.58 μg/mL).

Pharmacodynamics

VALCYTE allows systemic exposure of ganciclovir comparable to that achieved with recommended doses of intravenous (IV) ganciclovir, which has been shown to be efficacious in the treatment of CMV.

The clinical antiviral effect of VALCYTE has been demonstrated in the treatment of AIDS patients with newly diagnosed CMV retinitis (Study WV15376). CMV shedding was decreased in urine from 46% (32/69) of patients at study entry to 7% (4/55) of patients following four weeks of VALCYTE treatment.

Viral Resistance

Viral resistance to ganciclovir can arise after chronic dosing with valganciclovir by selection of mutations in either the viral kinase gene (UL97) responsible for ganciclovir monophosphorylation or the viral polymerase gene (UL54). UL97 mutations arise earlier and more frequently than mutations in UL54. Virus containing mutations in the UL97 gene is resistant to ganciclovir alone, with M460V/I, H520Q, C592G, A594V, L595S, C603W being the most frequently reported ganciclovir resistance-associated substitutions. Mutations in the UL54 gene may show cross-resistance to other antivirals targeting the viral polymerase and vice versa. Amino acid substitutions in UL54 conferring cross-resistance to ganciclovir and cidofovir are generally located within the exonuclease domains and region V, however amino acid substitutions conferring cross-resistance to foscarnet are diverse, but concentrate at and between regions II (codon 696-742) and III (codon 805-845).

Adult Patients

Treatment of CMV Retinitis in AIDS:

Genotypic analysis of CMV in polymorphonuclear leucocytes (PMNL) isolates from 148 patients enrolled in one clinical study has shown that 2.2% (3/137), 6.5% (8/123), 12.8% (13/101) and 15.3% (13/85) contain UL97 mutations after 3, 6, 12 and 18 months, respectively, of valganciclovir treatment (using the number of patients still on treatment at the assessment time as the denominator). Phenotypic resistance was not identified, but very few CMV culture isolates were available for analysis.

Prevention of CMV Disease in Transplantation:

Resistance was studied by genotypic analysis of CMV in PMNL samples collected i) on Day 100 (end of study drug prophylaxis) and ii) in cases of suspected CMV disease up to 6 months after transplantation. From the 245 patients randomised to receive valganciclovir, 198 Day 100 samples were available for testing and no ganciclovir resistance mutations were observed. This compares with 2 ganciclovir resistance mutations detected in the 103 samples tested (1.9%) for patients in the oral ganciclovir comparator arm.

Of the 245 patients randomised to receive valganciclovir, samples from 50 patients with suspected CMV disease were tested and no resistance mutations were observed. Of the 127 patients randomised on the ganciclovir comparator arm, samples from the 29 patients with suspected CMV disease were tested, from which two resistance mutations were observed, giving an incidence of resistance of 6.9%.

Resistance was evaluated in a study that extended valganciclovir CMV prophylaxis from 100 days to 200 days post-transplant in adult kidney transplant patients at high risk for CMV disease (D+/R-) (see CLINICAL TRIALS). Five subjects from the 100 day group and four subjects from the 200 day group meeting the resistance analysis criteria had known ganciclovir resistance-associated amino acid substitutions detected. In six subjects, the following resistance associated amino acid substitutions were detected within pUL97: 100 day group: A440V, M460V, C592G; 200 day group: M460V, C603W. In three subjects, the following resistance-associated amino acid substitutions were detected within pUL54: 100 day group: E315D, 200 day group: E315D, P522S. Overall, the detection of known ganciclovir resistance-associated amino acid substitutions was observed more frequently in patients during prophylaxis therapy than after the completion of prophylaxis therapy (during therapy: 5/12 [42%] versus after therapy: 4/58 [7%]). The possibility of viral resistance should be considered in patients who show poor clinical response or experience persistent viral excretion during therapy.

Pharmacokinetics

The pharmacokinetic properties of valganciclovir have been evaluated in HIV- and CMV-seropositive patients, patients with AIDS and CMV retinitis and in solid organ transplant patients.

The parameters which control the exposure of ganciclovir from valganciclovir are the oral absorption of valganciclovir and the renal excretion of ganciclovir.

Absorption and Bioavailability

Valganciclovir is a prodrug of ganciclovir, which is well absorbed from the gastrointestinal tract and rapidly metabolised in the intestinal wall and liver to ganciclovir. The absolute bioavailability of ganciclovir from valganciclovir is approximately 60%. Systemic exposure to valganciclovir is transient and low. AUC0-24h and Cmax values are approximately 1% and 3% of those of ganciclovir, respectively.

Dose proportionality with respect to ganciclovir AUC following administration of valganciclovir in the dose range 450 to 2625 mg was demonstrated only under fed conditions. When valganciclovir is given with food mean ganciclovir AUC0-24h> increased by 24% to 56% depending on the dose. When valganciclovir was given with food at a dose of 875 mg, increases were seen in both mean ganciclovir AUC0-224h (approximately 30%) and mean ganciclovir Cmax values (approximately 14%). Therefore, it is recommended that VALCYTE be administered with food (see DOSAGE AND ADMINISTRATION).

For ganciclovir, average AUC0-24h> has been shown to correlate with time to progression of CMV retinitis.

The bioavailability of ganciclovir from valganciclovir is comparable across all the patient populations studied (adult and paediatric). The systemic exposure of ganciclovir to heart, kidney and liver transplant recipients was similar after oral administration of valganciclovir according to the renal function dosing algorithm and paediatric dosing algorithm (see DOSAGE AND ADMINISTRATION).

Distribution

Due to the rapid conversion of valganciclovir to ganciclovir, protein binding of valganciclovir was not determined. Plasma protein binding of ganciclovir was 1% to 2%. The steady state volume of distribution of ganciclovir after IV administration was 0.680 ± 0.161 L/kg.

Metabolism

Valganciclovir is rapidly hydrolysed to ganciclovir; no other metabolites have been detected. No metabolite of orally-administered radiolabelled ganciclovir (1000 mg single dose) accounted for more than 1% to 2% of the radioactivity recovered in the faeces or urine.

Elimination

Following dosing with valganciclovir, renal excretion as ganciclovir by glomerular filtration and active tubular secretion is the major route of elimination of valganciclovir. Renal clearance accounts for 81.5% ± 22% of the systemic clearance of ganciclovir.

The terminal half-life (t½) of ganciclovir following oral administration of valganciclovir to either healthy or HIV- and CMV-positive subjects was 4.18 ± 0.80 hours (n = 244), and that following administration of IV ganciclovir was 3.85 ± 0.74 hours (n = 87).

In patients undergoing haemodialysis, approximately half of the ganciclovir present at the start of a dialysis session is removed during dialysis. The mean intra-dialysis half-life and the mean inter-dialysis half-life was estimated to be 3.47 hours and 51.0 hours, respectively.

Pharmacokinetics in Special Populations

Patients with renal impairment

Decreased renal function resulted in decreased clearance of ganciclovir from valganciclovir, and a corresponding increase in terminal half-life. Therefore, dosage adjustment is required for renally impaired patients (see PRECAUTIONS and DOSAGE AND ADMINISTRATION).

Patients with hepatic impairment

The pharmacokinetics of ganciclovir from valganciclovir in stable liver transplant recipients were investigated in one open label 4-part cross-over study (n = 28). The absolute bioavailability of ganciclovir from valganciclovir following a single dose of 900 mg valganciclovir under fed conditions was approximately 60%, in agreement with the estimates obtained in other patient populations. Ganciclovir AUC0-24h was comparable to that achieved by 5 mg/kg IV ganciclovir in liver transplant recipients.

Paediatric patients

Prevention of CMV disease in transplantation

The pharmacokinetics of ganciclovir following the administration of valganciclovir were characterised using a population PK model based on data from four studies in paediatric solid organ transplant patients aged 3 weeks to 16 years. PK data were evaluable from 119 of the 123 patients enrolled. In these studies, patients received daily intravenous doses of ganciclovir to produce exposure equivalent to an adult 5 mg/kg intravenous dose (70 kg reference body weight) and/or received oral doses of valganciclovir to produce exposure equivalent to an adult 900 mg dose.

The model indicated that clearance is influenced by body weight and creatinine clearance while the central and peripheral volumes of distribution were influenced by body weight (see DOSAGE AND ADMINISTRATION).

The mean ganciclovir Cmax, AUC and half-life by age and organ type in studies using the paediatric dosing algorithm are listed in Table 1 and are consistent with estimates obtained in adult solid organ transplant patients.


Table 1 Summary of model-estimated mean (±SD) pharmacokinetics of ganciclovir in paediatric patients by age

PK Parameter Age Group
Heart Transplant recipient
<4 months of ages
Solid Organ Transplant
patients
4 months to 16 years
< 4months
(n=14)
4 months -
≤ 2 years
(n = 2)
> 2 - <
12years
(n = 12)*
≥ 12 years
(n = 19)
Kidney AUC0-24h
(μg.h/mL)
- 65.2 (16.6) 55.0 (11.9) 50.0 (11.6)
(n = 33) Cmax (μg/mL) - 10.0 (0.04) 8.74 (2.49) 7.85 (2.10)
t½ (h) - 3.10 (0.59) 4.40 (1.41) 5.67 (1.06)
4 months -
≤ 2 years
(n = 9)
> 2 - < 12
years (n = 6)
≥ 12 years
(n = 2)
Liver AUC0-24h
(μg.h/mL)
- 69.4 (35.4) 58.4 (6.18) 35.6 (2.76)
(n = 17) Cmax (μg/mL) - 11.7 (3.59) 9.35 (2.33) 5.55 (1.34)
t½ (h) - 2.72 (1.32) 3.61 (0.80) 4.50 (0.25)
< 4 months
(n=14)
4 months ≤
2 years
(n = 6)
> 2 - < 12
years (n = 2)
≥ 12 years
(n = 4)
Heart AUC0-24h
(μg.h/mL)
68.1(19.8)† 56.3 (23.2) 60.0 (19.3) 61.2 (26.0)
(n = 26) Cmax (μg/mL) 10.5 (3.35) 8.22 (2.44) 12.5 (1.02) 9.50 (3.34)
t½ (h) 2.00 (0.19) 3.60 (1.73) 2.62 (0.65) 5.05 (0.70)

* There was one subject who received both a kidney and liver transplant. The PK profile for this subject has not been included in this table as it is not possible to determine whether the effects observed are from the kidney/liver transplant or neither. †n = 18 observations, 3 patients contributed more than one value

Congenital CMV

Ganciclovir pharmacokinetics following valganciclovir administration were also evaluated in 133 neonates aged 2 to 31 days with symptomatic congenital CMV disease in two studies.

In the first study, all patients received 6 mg/kg intravenous ganciclovir twice daily. Patients were then treated with oral valganciclovir, where the dose of valganciclovir powder for oral solution ranged from 14 mg/kg to 20 mg/kg twice daily. A dose of 16 mg/kg twice daily of valganciclovir powder for oral solution provided comparable ganciclovir exposure as 6 mg/kg intravenous ganciclovir twice daily in neonates, and also achieved ganciclovir exposure similar to the effective adult 5 mg/kg intravenous dose. In the second study, all patients received valganciclovir powder for oral solution at a dose of 16 mg/kg twice daily for 6 weeks and subsequently 96 out of 109 enrolled patients were randomised to continue receiving valganciclovir or placebo for 6 months.

The mean ganciclovir AUC0-12hr after oral dose administration of valganciclovir was approximately 23.2 μg.h/mL (equivalent to 46.4 μg.h/mL in AUC0-24hr) in the first study. Similar exposure was also observed in the second study.

CLINICAL TRIALS

Adult Patients

Study WV15376: Treatment of CMV Retinitis in AIDS

In a randomised, controlled study, 160 patients with AIDS and newly diagnosed CMV retinitis were randomised to receive treatment with either VALCYTE tablets (900 mg twice daily for 21 days, then 900 mg daily for 7 days) or with IV ganciclovir solution (5 mg/kg twice daily for 21 days, then 5 mg/kg daily for 7 days). Participants in the two treatment arms were comparable with respect to age, sex, weight, height and race. The mean age in the valganciclovir treatment arm was 39.6 years compared with 37.7 years in the ganciclovir arm. There was a higher proportion of males in each treatment group; 90% in the valganciclovir arm and 91% in the ganciclovir arm. The median CD4+ T-cell count at screening was 20.0 cells/μL for patients on the valganciclovir arm, and 26.0 cells/μL for patients on the ganciclovir arm; and the median HIV viral load was 4.8 log10 copies/mL in the valganciclovir arm and 4.9 log10 copies/mL in the ganciclovir arm.

In the final analysis of CMV retinitis progression by week 4 based on masked assessment of fundus photographs, 146 of 160 patients were included (73 in the VALCYTE tablets group and 73 in the IV ganciclovir group). The proportion of patients with retinitis progression at week 4 was the same in both treatment groups: 0.099 for the VALCYTE treatment group and 0.1 for the ganciclovir treatment group. The difference in progression proportions (IV ganciclovir minus VALCYTE tablets) was 0.001, with a 95% confidence interval of -0.097 to 0.100.

After week 4, all patients in this study were allowed to continue to receive treatment with VALCYTE tablets given at the dosage of 900 mg once daily. The mean (median) time from randomisation to progression of CMV retinitis in the group receiving induction and maintenance treatment with VALCYTE tablets (n = 80) was 226 (160) days and in the group receiving induction treatment with IV ganciclovir and maintenance treatment with VALCYTE tablets (n = 80) was 219 (125) days.

Satisfactory induction was achieved at week 4 in 47/61 (77%) patients given ganciclovir and 46/64 (72%) patients given valganciclovir. Satisfactory induction was defined as no progression, no increase in lesion activity and a reduction in retinitis border activity. Response was reassessed at 6 weeks when 39/62 (63%) patients given ganciclovir and 39/56 (70%) patients given valganciclovir maintained a satisfactory response to induction therapy. Three (8%) patients in each group had active retinitis at the week 6 assessment.

Study PV16000: Prevention of CMV Disease in Solid Organ Transplantation

A double-blind, double-dummy clinical active comparator study has been conducted in 372 heart, liver and kidney transplant patients at high-risk for CMV disease (Donor seropositive/Recipient seronegative [(D+/R-)]). The study was designed to test for non-inferiority between the 2 treatment arms. Patients were randomised (2 valganciclovir: 1 oral ganciclovir) to receive either VALCYTE (900 mg once daily) or oral ganciclovir (1000 mg three times daily) starting within 10 days of transplantation until Day 100 post-transplant.

The primary analysis of the primary endpoint, the proportion of patients who developed CMV disease, including CMV syndrome and/or tissue invasive disease during the first 6 months post-transplant was 12.1% in the valganciclovir arm (n = 239) compared with 15.2% in the oral ganciclovir arm (n = 125) as assessed by a blinded Endpoint Committee. The study achieved its objective and it was concluded that valganciclovir was non-inferior to oral ganciclovir for the prevention of CMV disease in solid organ transplant patients.

The majority of cases of CMV disease occurred following cessation of prophylaxis (post-Day 100) with cases in the valganciclovir arm occurring on average later than those in the oral ganciclovir arm. The incidence of acute rejection in the first 6 months was 29.7% in patients randomised to valganciclovir compared with 36.0% in the oral ganciclovir arm. For a summary of PV16000 see Table 2 below.


Table 2 Summary of CMV disease (as assessed by the Endpoint Committee) and acute graft rejection up to 6 months post-transplant (ITT population)

No. of Patients
(PV16000)
Ganciclovir
(n = 125)
Valganciclovir
(n = 239)
Total
(n = 364)
Weighted
Difference in
Proportions
(95% CI)
(%) (%) (%)
Patients with CMV disease 19 15.2 29 12.1 48 13.2 3.4% -4.2%,
11.0%*
CMV syndrome 13 10.4 12 5.0 25 6.9
Tissue-invasive CMV 6 4.8 17 7.1 2.3 6.3
Acute Graft Rejection 45 36.0 71 29.7 116 31.9

*If the lower limit of the 95% CI is ≥ -0.05, then valganciclovir is non-inferior to ganciclovir. As the lower limit of the 95% confidence interval (-0.042) was above the pre-specified non-inferiority value of -0.05, non-inferiority was achieved.


For study PV16000 a population pharmacokinetics analysis was conducted using plasma samples taken from 160/245 patients in the valganciclovir arm and 82/127 patients in the oral ganciclovir arm, and from this analysis it was estimated that the median exposure to ganciclovir from valganciclovir was 1.74 times higher than seen with oral ganciclovir (AUC0-24h 44.3 vs. 25.4 μg.h/mL).

IMPACT Study (Study NT18435): Prevention of CMV Disease in Kidney Transplant Patients

A double-blind, placebo controlled study has been conducted in 326 kidney transplant patients at high risk of CMV disease (D+/R-) to assess the efficacy and safety of extending valganciclovir CMV prophylaxis from 100 to 200 days post-transplant.

The inclusion criteria in this study required the patients to have adequate haematological (absolute neutrophil count > 1000 cells/μL, platelets > 25,000/μL, haemoglobin > 8 g/dL) and renal function (creatinine clearance > 15 mL/min and improving) in the immediate post-transplant period. The mean age of the patients who participated in this trial was about 48 years.

Patients were randomised (1:1) to receive VALCYTE tablets (900 mg once daily) within 10 days of transplantation until Day 200 post-transplant or until Day 100 post-transplant followed by 100 days placebo.

The proportion of patients who developed CMV disease during the first 12 months post-transplant is shown in Table 3.

Table 3 Percentage of kidney transplant patients with CMV disease1, 12 month ITT population

100-day group 200-day group Treatment
difference
(95% CI)
Patients with confirmed or assumed CMV disease2 71/163
(43.6%)
36/155
(23.2%)
-20.3%
(-30.8%, -9.9%)
Patients with confirmed CMV disease 60/163
(36.8%)
25/155
(16.1%)
-20.7%
(-30.4%, -10.9%)

1 CMV Disease is defined as either CMV syndrome or tissue invasive CMV. 2 Confirmed CMV is a clinically confirmed case of CMV disease. Patients were assumed to have CMV disease if there was either no week 52 assessment or no confirmation of CMV disease before this time point.


The graft survival rate at 12 months post-transplant was 98.2% (160/163) for the 100-day dosing regimen and 98.1% (152/155) for the 200-day dosing regimen. The incidence of biopsy proven acute rejection at 12 months post-transplant was 17.2% (28/163) for the 100-day dosing regimen and 11.0% (17/155) for the 200-day dosing regimen.

No clinical trials have been conducted in patients following haematological or lung transplants.

Paediatric Patients

Prevention of CMV disease in transplantation

Valganciclovir powder for oral solution has been studied in five open-label, multi-centre clinical trials in paediatric solid transplant (SOT) patients.

Three of these studies assessed only the pharmacokinetics and safety of oral valganciclovir in SOT patients aged from 4 weeks to 16 years of age who were requiring CMV prophylaxis (see PHARMACOLOGY, Pharmacokinetics in Special Populations).

One study enrolled 20 liver transplant patients with a median age of 2 years (6 months to 16 years) who received a single daily dose of valganciclovir on 2 consecutive days. A second study enrolled 26 kidney patients with a median age of 12 years (1 to 16 years) who received multiple doses of valganciclovir on 2 consecutive days. The third study enrolled 14 heart transplant patients with a median age of 13 weeks (4 weeks to 125 days) who received a single daily dose of valganciclovir on 2 consecutive days. The other two studies assessed the development of CMV disease, as a measure of efficacy, following prophylaxis of valganciclovir for up to 100 days and 200 days post-transplant using the described paediatric dosing algorithm (see DOSAGE AND ADMINISTRATION).

One solid organ transplant study enrolled 63 paediatric kidney, liver or heart patients with a median age of 9 years (4 months to 16 years) who received daily doses of valganciclovir for up to 100 days. There was no CMV event reported during the study that would fulfil the definition of CMV disease. CMV events were reported in 7 patients during the study of which 3 did not require adjustment to the study drug or were not treated and, therefore, were not considered clinically significant (see ADVERSE EFFECTS, CLINICAL TRIALS and PHARMACOLOGY, Pharmacokinetics). The second study in solid organ transplant enrolled 57 paediatric kidney patients with a median age of 12 years (1 to 16 years) who received daily doses of valganciclovir for up to 200 days. There was no CMV event reported during the study that would fulfill the definition of CMV disease. While 4 patients reported CMV events, one could not be confirmed by the central laboratory and of the 3 remaining events one did not require treatment and, therefore, was not considered clinically significant (see ADVERSE EFFECTS, Clinical Trials).

Congenital CMV

The efficacy and safety of ganciclovir and/or valganciclovir were studied in neonates and infants with congenital symptomatic CMV infection in two studies, with patients receiving up to 6 weeks or 6 months of treatment. The dose of valganciclovir that was determined in the first study and carried forward to the second study was twice daily doses of VALCYTE oral solution based on body weight using the following equation: Dose (mg) = 16 mg per kg of body weight.

Efficacy was evaluated using relevant endpoints such as hearing outcomes, neurodevelopmental outcomes and correlations of CMV blood viral load with ganciclovir plasma concentrations and hearing (see ADVERSE EFFECTS, Clinical Trials).

Indications

VALCYTE is indicated for the treatment of cytomegalovirus (CMV) retinitis in adult patients with acquired immunodeficiency syndrome (AIDS).

VALCYTE is indicated for the prophylaxis of CMV disease in adult and paediatric solid organ transplantation (SOT) patients who are at risk.

Contraindications

VALCYTE is contraindicated in patients with known hypersensitivity to valganciclovir, ganciclovir or to any component of the product.

Due to the similarity of the chemical structure of valganciclovir and that of aciclovir and valaciclovir, a cross-hypersensitivity reaction between these medicines is possible.

VALCYTE should not be administered if the absolute neutrophil count is less than 500 cells/μL, the platelet count is less than 25 000/μL, or the haemoglobin is less than 8 g/dL.

Precautions

Clinical toxicities of VALCYTE, which is metabolised to ganciclovir, include leucopenia and thrombocytopenia. Concomitant administration of VALCYTE and other medicines that are known to be myelosuppressive or associated with renal impairment may result in added toxicity (see PRECAUTIONS, Interactions with Other Medicines).

In animal studies ganciclovir was found to be mutagenic, clastogenic, aspermatogenic, teratogenic and carcinogenic; therefore it should be considered a potential teratogen and carcinogen in humans with potential to cause birth defects and cancers. It is also considered likely that VALCYTE causes temporary or permanent inhibition of spermatogenesis (see PRECAUTIONS, Carcinogenicity, Genotoxicity). VALCYTE is indicated in those patients as outlined under the INDICATIONS section where the potential benefits to the patient outweighs the risks stated herein.

The diagnosis of CMV retinitis should be made by indirect ophthalmoscopy. Other conditions in the differential diagnosis of CMV retinitis include candidiasis, toxoplasmosis, histoplasmosis, retinal scars and cotton wool spots, any of which may produce a retinal appearance similar to CMV. For this reason it is essential that the diagnosis of CMV be established by an ophthalmologist familiar with the presentation of these conditions. The diagnosis of CMV retinitis may be supported by culture of CMV in the urine, blood, throat, or other sites, but a negative culture does not rule out CMV retinitis.

Haematologic

Severe leucopenia, neutropenia, anaemia, thrombocytopenia, pancytopenia, bone marrow depression and aplastic anaemia have been observed in patients treated with VALCYTE (and ganciclovir) (see ADVERSE EFFECTS and DOSAGE AND ADMINISTRATION).

Therapy should not be initiated if the absolute neutrophil count is less than 500 cells/μL; or platelet count is less than 25 000/μL; or the haemoglobin is less than 8 g/dL. It is recommended that complete blood counts and platelet counts be monitored frequently during therapy; especially in patients in whom ganciclovir or other nucleoside analogues have previously resulted in leucopenia, or in whom neutrophil counts are less than 1000 cells/μL at the beginning of treatment.

VALCYTE should, therefore, be used with caution in patients with pre-existing cytopenias, or who have received or are receiving myelosuppressive medicines or irradiation. Cytopenia may occur at any time during treatment and may increase with continued dosing. In patients with severe leucopenia, neutropenia, anaemia and/or thrombocytopenia, it is recommended that treatment with haematopoietic growth factors and/or dose interruption be considered. Cell counts usually begin to recover within 3 to 7 days of discontinuing medication. Colony-stimulating factors have been shown to increase neutrophil counts in patients receiving ganciclovir for treatment of CMV retinitis.

Renal Impairment

In patients with impaired renal function, dosage adjustments based on creatinine clearance are required.

Increased serum creatinine levels have been observed in trials evaluating VALCYTE tablets. Patients should have serum creatinine or creatinine clearance values monitored carefully to allow for dosage adjustments in renally impaired patients (see DOSAGE AND ADMINISTRATION, Special Patient Groups).

Effects on Fertility

In animal studies ganciclovir was found to be aspermatogenic. It is therefore considered likely that VALCYTE causes temporary or permanent inhibition of spermatogenesis.

Reproductive toxicity studies have not been conducted with valganciclovir. Valganciclovir is rapidly and extensively converted to ganciclovir and therefore is expected to have similar reproductive toxicity effects as ganciclovir. Animal data indicate that the administration of ganciclovir causes inhibition of spermatogenesis and subsequent infertility. These effects were reversible at lower doses and irreversible at higher doses. It is considered probable that in humans, valganciclovir at the recommended doses may cause temporary or permanent inhibition of spermatogenesis. Ganciclovir caused decreased mating behaviour, decreased fertility, and an increased incidence of embryolethality in female mice following IV doses of 90 mg/kg/day (approximately 2.1 times the mean drug exposure to ganciclovir in humans following the maximum recommended dose of valganciclovir, 900 mg twice daily, based on AUC comparisons).

Ganciclovir caused decreased fertility in male mice and hypospermatogenesis in mice and dogs following daily oral or IV administration of doses ranging from 0.2 to 10 mg/kg/day. Systemic drug exposure (AUC) at the lowest dose showing toxicity in each species ranged from 0.02 to 0.1 times the AUC of ganciclovir in humans following the maximum recommended dose of valganciclovir. Valganciclovir caused similar effects on spermatogenesis in mice, rats and dogs. It is considered likely that valganciclovir could cause inhibition of human spermatogenesis.

Use in Pregnancy - Category D

Women of childbearing potential should be advised to use effective contraception during treatment with valganciclovir because of the mutagenic and teratogenic potential of ganciclovir. Men should be advised to practise barrier contraception during, and for at least 90 days following, treatment with valganciclovir.

Valganciclovir is expected to have reproductive toxicity effects similar to ganciclovir. Ganciclovir has been shown to be embryotoxic in rabbits and mice following IV administration, and teratogenic in rabbits. Foetal resorptions were present in at least 85% of rabbits at 60 mg/kg/day IV and mice at 108 mg/kg/day (2.7 times the mean drug exposure to ganciclovir in humans following the maximum recommended dose of valganciclovir, 900 mg twice daily, based on AUC comparisons). Effects observed in rabbits included: foetal growth retardation, embryolethality, teratogenicity and/or maternal toxicity. Teratogenic changes included cleft palate, anophthalmia/microphthalmia, aplastic organs (kidney and pancreas), hydrocephaly and brachygnathia. In mice, effects observed were foetal toxicity and embryolethality.

Daily intravenous doses of 90 mg/kg administered to female mice prior to mating, during gestation, and during lactation caused hypoplasia of the testes and seminal vesicles in the month-old male offspring, as well as pathologic changes in the nonglandular region of the stomach. The drug exposure in mice as estimated by the AUC was approximately 2.1 times the human AUC.

Valganciclovir may be teratogenic or embryotoxic at dose levels recommended for human use. In addition, the effect on the future fertility of boys is unknown. There are no adequate and well-controlled studies in pregnant women. The safety of VALCYTE for use in human pregnancy has not been established. VALCYTE should be used during pregnancy only if the potential benefit justifies the potential risk to the foetus.

Use in Lactation

It is not known whether ganciclovir is excreted in human or animal milk. However, many medicines are excreted in human milk and, because carcinogenic and teratogenic effects occurred in animals treated with ganciclovir, the possibility of serious adverse reactions from ganciclovir in breastfed infants is considered likely. Therefore VALCYTE should not be given to breastfeeding mothers or breastfeeding should be discontinued. The minimum time interval before breastfeeding can safely be resumed after the last dose of VALCYTE is unknown.

Paediatric Use

The use of VALCYTE in children warrants extreme caution. VALCYTE should be considered a potential carcinogen in humans. This potential to cause cancers is greater in infants and children than in adults. VALCYTE is likely to cause temporary or permanent inhibition of spermatogenesis. This could result in permanent male infertility. Administration to children should be undertaken only after careful evaluation and only if, in the opinion of the physician, the potential benefits of treatment outweigh these considerable risks (see CLINICAL TRIALS, DOSAGE and ADMINISTRATION, ADVERSE EFFECTS).

Use in the Elderly

The pharmacokinetic profiles of VALCYTE in elderly patients have not been established. Since elderly individuals frequently have a reduced glomerular filtration rate, particular attention should be paid to assessing renal function before and during administration of VALCYTE.

Clinical studies of VALCYTE did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other therapy. VALCYTE is known to be substantially excreted by the kidney, and the risk of toxic reactions to this medicine may be greater in patients with impaired renal function. Since elderly patients are more likely to have decreased renal function, care should be taken in dose selection. In addition, renal function should be monitored and dosage adjustments should be made accordingly (see PRECAUTIONS, Renal Impairment; and DOSAGE AND ADMINISTRATION, Patients with Renal Impairment).

Carcinogenicity

Ganciclovir was genotoxic and carcinogenic in animal studies. VALCYTE should be considered a potential carcinogen in humans with the potential to cause cancers. No long-term carcinogenicity studies have been conducted with valganciclovir. However, upon oral administration, valganciclovir is rapidly and extensively converted to ganciclovir.

Toxicity in mice, dogs and rats was primarily characterised by testicular atrophy. Male infertility occurred at doses of 2 mg/kg/day and above which was consistent with the infertility and testicular atrophy seen in toxicity studies with doses between 2 and 10 mg/kg/day. In females, a more complex range of effects were induced which were characterised by embryo-foetal abnormalities and embryo-foetal losses in mice and rabbits and in multi-dose studies, by toxic and eventually carcinogenic changes to the reproductive system in mice.

Ganciclovir was carcinogenic in the mouse after oral doses of 20 mg/kg/day for 18 months and 1000 mg/kg/day for 15 months. All ganciclovir-induced tumours were of haematopoietic epithelial or vascular origin. Epithelial tumours involved a wide variety of tissues, including the female reproductive organs, pancreas, gastrointestinal tract and skin, as well as rodent specific glands (perputial, clitoral and Harderian). Vascular tumours were observed in females, mainly in the reproductive organs, but also in the mesenteric lymph nodes and liver. No carcinogenic effects occurred at 1 mg/kg/day. Based on data on plasma drug concentrations, exposure of humans to ganciclovir would be similar to or greater than the exposure of mice in the above study at 1000 mg/kg/day. This potential is likely to be markedly greater in children, as cell division occurs more rapidly in children.

Genotoxicity

Valganciclovir increased mutations in mouse lymphoma cells and was clastogenic in the mouse micronucleus assay. Valganciclovir was not mutagenic in the Ames Salmonella assay.

Ganciclovir increased mutations in mouse lymphoma cells and DNA damage in human lymphocytes in vitro. Ganciclovir was clastogenic in the mouse micronucleus assay. Ganciclovir was not mutagenic in the Ames Salmonella assay.

Effects on Ability to Drive and Use Machines

Convulsions, sedation, dizziness, ataxia and/or confusion have been reported with the use of VALCYTE and/or ganciclovir. If they occur, such effects may affect tasks requiring alertness including the patient’s ability to drive and operate machinery.

Interaction With Other Medicines

In a rat in situ model of intestinal permeability, there was no interaction of valaciclovir, didanosine, nelfinavir, cyclosporin, omeprazole and mycophenolate mofetil with valganciclovir.

Valganciclovir is rapidly and extensively converted to ganciclovir; therefore interactions associated with ganciclovir will be expected for VALCYTE.

Binding of ganciclovir to plasma proteins is only about 1% to 2%, and medicine interactions involving binding site displacement are not anticipated.

Imipenem-cilastatin

Convulsions have been reported in patients taking ganciclovir and imipenem-cilastatin concomitantly. VALCYTE should not be administered concomitantly with imipenem-cilastatin unless the potential benefits outweigh the potential risks (see PRECAUTIONS).

Probenecid

Probenecid given with oral ganciclovir resulted in statistically significantly decreased renal clearance of ganciclovir (20%) leading to statistically significantly increased exposure (40%). These changes were consistent with a mechanism of interaction involving competition for renal tubular excretion. Therefore patients taking probenecid and VALCYTE concomitantly should be closely monitored for ganciclovir toxicity.

Zidovudine

When zidovudine was given in the presence of oral ganciclovir there was a small (17%), but statistically significant, increase in the AUC of zidovudine. There was also a trend towards lower ganciclovir concentrations when administered with zidovudine although this was not statistically significant. However, since both zidovudine and valganciclovir have the potential to cause neutropenia and anaemia, some patients may not tolerate concomitant therapy at full dosage.

Didanosine

Didanosine plasma concentrations were found to be consistently raised when given with ganciclovir (both IV and oral). At ganciclovir oral doses of 3 g/day and 6 g/day, an increase in the AUC of didanosine ranging from 84% to 124% has been observed, and likewise at IV doses of 5 mg/kg/day and 10 mg/kg/day, and increase in the AUC of didanosine ranging from 38% to 67% has been observed. This increase cannot be explained by competition for renal tubular secretion, as there was an increase in the percentage of didanosine dose excreted. This increase could arise from either increased bioavailability or decreased metabolism. There was no clinically significant effect on ganciclovir concentrations. However, given the increase in didanosine plasma concentrations in the presence of ganciclovir, patients should be closely monitored for didanosine toxicity.

Mycophenolate mofetil

Based on the results of a single dose administration study of recommended doses of oral mycophenolate mofetil (MMF) and IV ganciclovir and the known effects of renal impairment on the pharmacokinetics of MMF and ganciclovir, it is anticipated that co-administration of these medicines (which have the potential to compete for renal tubular secretion) will result in increases in phenolic glucuronide of mycophenolic acid (MPAG) and ganciclovir concentration. No substantial alteration of mycophenolic acid (MPA) pharmacokinetics is anticipated and MMF dose adjustment is not required. In patients with renal impairment in which MMF and ganciclovir are co-administered, the dose recommendation of ganciclovir should be observed and patients monitored carefully.

Zalcitabine

Zalcitabine increased the AUC0-8h of oral ganciclovir by 13%. There were no statistically significant changes in any of the other pharmacokinetic parameters assessed. Additionally, there were no clinically relevant changes in zalcitabine pharmacokinetics in the presence of oral ganciclovir although a small increase in the elimination rate constant was observed.

Stavudine

No statistically significant pharmacokinetic interaction was observed when stavudine and oral ganciclovir were given in combination.

Trimethoprim

Trimethoprim statistically significantly decreased the renal clearance of oral ganciclovir by 16.3% and this was associated with a statistically significant decrease in the terminal elimination rate and corresponding increase in half-life by 15%. However, these changes are unlikely to be clinically significant, as AUC0-8h and Cmax were unaffected. The only statistically significant change in trimethoprim pharmacokinetic parameters when co-administered with ganciclovir was an increase in Cmin by 12%. However, this is unlikely to be of clinical significance and no dose adjustment is recommended.

Cyclosporin

There was no evidence that introduction of ganciclovir affects the pharmacokinetics of cyclosporin based on the comparison of cyclosporin trough concentrations. However, there was some evidence of increases in the maximum serum creatinine value observed following initiation of ganciclovir therapy.

Other Potential Medicine Interactions

Since ganciclovir is excreted through the kidney via glomerular filtration and active tubular secretion (see PHARMACOLOGY, Pharmacokinetics, Elimination), coadministration of valganciclovir with antiretroviral drugs that share the tubular secretion pathway, such as nucleos(t)ide reverse transcriptase inhibitors, may change the plasma concentrations of valganciclovir and/or the coadministered drug.

Toxicity may be enhanced when ganciclovir is co-administered with other medicines known to be myelosuppressive or associated with renal impairment (such as dapsone, pentamidine, flucytosine, vincristine, vinblastine, adriamycin, amphotericin B, nucleoside analogues, hydroxyurea and pegylated interferons/ribavirin). Therefore, these medicines should be considered for concomitant use with ganciclovir only if the potential benefits outweigh the potential risks.

Adverse Effects

Clinical Trials

Experience with VALCYTE

Valganciclovir, a prodrug of ganciclovir, is rapidly converted to ganciclovir after oral administration. The undesirable effects known to be associated with ganciclovir usage can therefore be expected to occur with VALCYTE. All of the adverse events observed in clinical studies with VALCYTE have been previously observed with ganciclovir.

Adult Patients

Treatment of CMV Retinitis in AIDS

The safety profiles of VALCYTE and IV ganciclovir during 28 days of randomised study phase (21 days induction dose and 7 days maintenance dose) in 158 patients were comparable. The most frequently reported events were diarrhoea, neutropenia and pyrexia. More patients reported diarrhoea, oral candidiasis, headache and fatigue in the oral valganciclovir arm, and nausea and injection site-related events in the IV ganciclovir arm (see Table 4).


Table 4 Percentage of patients with selected adverse events occurring during the randomised study phase

Adverse event Valganciclovir arm
(n = 79)
IV ganciclovir arm
(n = 79)
Diarrhoea 16% 10%
Oral candidiasis 11% 6%
Headache 9% 5%
Fatigue 8% 4%
Nausea 8% 14%
Venous phlebitis and thrombophlebitis - 6%

Based on two clinical trials (n = 370) where patients with CMV retinitis received VALCYTE at a dosage of 900 mg twice daily or once daily, corresponding to the induction or maintenance regimen, respectively, the adverse events with an incidence of ≥ 5%, regardless of seriousness and drug relationship is shown in Table 5. Approximately 65% of these patients received VALCYTE for more than nine months (maximum duration was 30 months).

The most frequently reported adverse reactions regardless of seriousness, that were considered related (remotely, possibly or probably) to VALCYTE by the investigator were neutropenia, anaemia, diarrhoea and nausea.

Prevention of CMV Disease in Transplantation

Table 5 also shows the adverse events (up to 28 days after study treatment) regardless of seriousness and drug relationship with an incidence of ≥ 5% from a clinical trial, where solid organ transplant patients received valganciclovir or oral ganciclovir starting within 10 days post-transplantation until Day 100 post-transplant.

The most frequently reported adverse reactions, regardless of seriousness, that were considered related (remotely, possibly or probably) to valganciclovir by the investigator in solid organ transplant patients treated until Day 100 post-transplant were leukopenia, diarrhoea, nausea and neutropenia and were leukopenia, neutropenia, anaemia and diarrhoea in kidney transplant patients treated until Day 200 post-transplant.

Table 5 Percentage of patients with adverse events occurring in ≥ 5% of patients in either CMV retinitis or solid organ transplantation clinical trials treated with valganciclovir or ganciclovir

Patients with
CMV retinitis
Solid Organ Transplant Patients
Dosing until Day 100
Post-Transplant
Valganciclovir Valganciclovir Oral ganciclovir
System organ class (n = 370) % (n = 244) % (n = 126) %
Gastrointestinal disorders
Diarrhoea 38 30 29
Nausea 25 23 23
Vomiting 20 16 14
Abdominal pain 13 14 14
Constipation 6 20 20
Abdominal pain upper 6 9 6
Dyspepsia 4 12 10
Abdominal distention 2 6 6
Ascites - 9 6
General disorders and administration site conditions
Pyrexia 26 13 14
Fatigue 20 13 15
Oedema lower limb 5 21 16
Pain 3 5 7
Oedema 1 11 9
Oedema peripheral 1 6 7
Weakness 4 6 6
Blood and lymphatic system disorders
Neutropenia 24 8 3
Anaemia 22 12 15
Thrombocytopenia 5 5 5
Leucopenia 4 14 7
Infections and infestations
Oral candidiasis 20 3 9
Pharyngitis/nasopharyngitis 12 4 8
Sinusitis 10 3 -
Upper respiratory tract infection 9 7 7
Influenza 9    
Pneumonia 7 4 2
Bronchitis 6 - 1
Pneumocystis carinii pneumonia 6 - -
Urinary tract infection 5 11 9
Nervous system disorders
Headache 18 22 27
Insomnia 14 20 16
Peripheral neuropathy 7 1 1
Paresthesia 6 5 5
Tremors 2 28 25
Dizziness (excl. vertigo) 9 10 6
Skin and subcutaneous tissue disorders
Dermatitis (all types) 18 4 5
Night sweats 7 3 4
Pruritus 6 7 4
Acne <1 4 6
Rash (all types) 9 <1 -
Respiratory, thoracic and mediastinal disorders
Cough 16 6 8
Dyspnoea 9 11 10
Productive cough 5 2 2
Rhinorrhea 2 4 6
Pleural effusion <1 7 8
Eye Disorders
Retinal detachment 13 - -
Vision blurred 6 1 4
Psychiatric disorders
Depression 9 7 6
Investigations
Weight decrease 9 3 3
Blood creatinine increased 1 10 14
Musculoskeletal and connective tissue disorders
Back pain 8 20 15
Arthralgia 6 7 7
Muscle cramps 2 6 11
Pain in limb 3 5 7
Renal and urinary disorders
Renal impairment 1 7 12
Dysuria 2 7 6
Immune system disorders
Graft and transplant rejection - 24 30
Metabolism and nutrition disorders
Anorexia 5 3 -
Cachexia 5 - -
Hyperkalaemia <1 14 14
Hypokalaemia 2 8 8
Hypomagnesaemia <1 8 8
Hyperglycaemia 1 6 7
Appetite decreased 8 4 5
Dehydration 6 5 6
Hypophosphataemia <1 9 6
Hypocalcaemia <1 4 6
Hepatobiliary disorders
Hepatic function abnormal 3 9 11
Surgical and medical Procedures
Post-operative complications 1 12 8
Post-operative pain 2 13 7
Post-operative wound infection 1 11 6
Injury, poisoning and procedural complication
Wound drainage increased - 5 9
Wound dehiscence <1 5 6
Vascular disorders
Hypotension 1 3 8
Hypertension 3 18 15

Serious adverse events for VALCYTE from these three clinical trials (n = 934) with a frequency of less than 5% and which are not mentioned in the two tables above, are listed below:

Blood and lymphatic system disorders: pancytopenia, bone marrow depression, aplastic anaemia, febrile neutropenia

Renal and urinary disorders: decreased renal creatinine clearance

Infections and infestations: local and systemic infections and sepsis

Bleeding complications: potentially life-threatening bleeding associated with thrombocytopenia

Nervous system disorders: convulsion, psychotic disorder, hallucinations, confusion, agitation

General disorder and administration site conditions: valganciclovir hypersensitivity

Severe neutropenia (ANC < 500/μL) is seen more frequently in CMV retinitis patients (16%) undergoing treatment with valganciclovir than in solid organ transplant patients receiving valganciclovir (5%) or oral ganciclovir (3%) until Day 100 post-transplant or valganciclovir (10%) until Day 200 post-transplant. There was a greater increase in serum creatinine seen in solid organ transplant patients treated until Day 100 or Day 200 post-transplant with both valganciclovir and oral ganciclovir when compared to CMV retinitis patients. Impaired renal function is a feature common to solid organ transplantation patients.

The overall safety profile of VALCYTE did not change with the extension of prophylaxis up to 200 days in high risk kidney transplant patients. Leucopenia was reported with a slightly higher incidence in the 200 days arm while the incidence of neutropenia, anaemia and thrombocytopenia were similar in both arms.

The incidence of adverse events in this patient population from the IMPACT study is shown in Tables 6 and 7. Table 6 shows adverse events occurring in the first 100 days of the study when all patients were receiving valganciclovir prophylaxis. While, Table 7 shows adverse events occurring after day 100 of the study when only patients in the 200 days arm were receiving valganciclovir (patients in the 100 day arm were receiving placebo).

Table 6 Adverse events occurring in ≥ 5% of high risk kidney transplant patients treated with valganciclovir (IMPACT Study, Days 1 - 100)

System organ class 100-day arm
(n = 164)
n(%)
200-day arm
(n = 156)
n(%)
Gastrointestinal disorders
Diarrhoea 29 (18) 42 (27)
Constipation 22 (13) 14 (9)
Nausea 14 (9) 13 (8)
Abdominal pain 7 (4) 10 (6)
Dyspepsia 3 (2) 10 (6)
Vomiting 5 (3) 8 (5)
Blood and lymphatic system disorders
Leucopenia 33 (20) 31 (20)
Anaemia 21 (13) 20 (13)
Neutropenia 20 (12) 15 (10)
General disorders and administration site conditions
Oedema peripheral 29 (18) 26 (17)
Pyrexia 11 (7) 10 (6)
Fatigue 4 (2) 12 (8)
Infections and infestations
Urinary tract infection 17 (10) 30 (19)
Nasopharyngitis 14 (9) 3 (2)
Upper respiratory tract infection 10 (6) 4 (3)
Nervous system disorders
Tremor 15 (9) 23 (15)
Headache 14 (9) 9 (6)
Insomnia 10 (6) 10 (6)
Metabolism and nutrition disorders
Hypophosphataemia 19 (12) 18 (12)
Hyperkalaemia 18 (11) 15 (10)
Hypomagnesaemia 16 (10) 7 (4)
Hyperglycaemia 9 (5) 4 (3)
Vascular disorders
Hypertension 19 (12) 12 (8)
Hypotension 9 (5) 2 (1)
Investigations
Blood creatinine increased 16 (10) 11 (7)
Renal and urinary disorders
Haematuria 7 (4) 10 (6)
Immune system disorders
Transplant rejection 9 (5) 6 (4)
Respiratory, thoracic and mediastinal disorders
Dyspnoea 8 (5) 6 (4)
Cough 8 (5) 3 (2)

Table 7 Adverse events occurring in ≥ 5% of high risk kidney transplant patients treated with valganciclovir (IMPACT Study, Day 101 onwards)

System organ class 100-day arm
(n = 164)
n(%)
200-day arm
(n = 156)
n(%)
Blood and lymphatic system disorders
Leucopenia 7 (4) 30 (19)
Neutropenia 5 (3) 8 (5)
Gastrointestinal disorders
Diarrhoea 18 (11) 15 (10)
Infections and infestations
Urinary tract infection 11 (7) 11 (7)
Cytomegalovirus infection 20 (12) 1 (<1)
Nasopharyngitis 7 (4) 10 (6)
Upper respiratory tract infection 4 (2) 11 (7)
Cytomegalovirus syndrome 12 (7) -
General disorders and administration site conditions
Pyrexia 10 (6) 6 (4)
Respiratory, thoracic and mediastinal disorders
Cough 9 (5) 4 (3)

Experience with Ganciclovir

Valganciclovir is rapidly converted to ganciclovir. Adverse events reported with ganciclovir, and not mentioned above, are listed below.

Gastrointestinal disorders:cholangitis, dysphagia, eructation, oesophagitis, faecal incontinence, flatulence, gastritis, gastrointestinal disorder, gastrointestinal haemorrhage, mouth ulceration, pancreatitis, tongue disorder

General disorders and administration site conditions: asthenia, bacterial, fungal and viral infections, haemorrhage, malaise, mucous membrane disorder, photosensitivity reaction, rigors, sepsis, taste disturbance, decreased libido

Hepatobiliary disorders: hepatitis, jaundice

Skin and subcutaneous tissue disorders: acne, alopecia, exfoliative dermatitis, dry skin, increased sweating, urticaria

Nervous system disorders: abnormal dreams, amnesia, anxiety, ataxia, coma, dry mouth, emotional disturbance, hyperkinetic syndrome, hypertonia, myoclonic jerks, nervousness, somnolence, tremor

Psychiatric disorder: abnormal thinking

Musculoskeletal and connective tissue disorders: musculoskeletal pain, myasthenic syndrome

Renal and urinary disorders: haematuria present, impotence, renal failure, urinary frequency

Metabolic and nutritional disorders: increased blood alkaline phosphatase, increased blood creatine phosphokinase, decreased blood glucose, increased blood lactic dehydrogenase, decreased blood magnesium, diabetes mellitus, oedema, abnormal hepatic function, hypocalcaemia, hypokalaemia, hypoproteinaemia

Eye disorders: amblyopia, blindness, eye haemorrhage, eye pain, glaucoma, abnormal vision, vitreous disorder

Ear and labyrinth disorders: earache, deafness, tinnitus

Blood and lymphatic system disorders: eosinophilia, leucocytosis, lymphadenopathy, splenomegaly

Cardiac disorders: arrhythmia (including ventricular arrhythmia), deep thrombophlebitis, hypertension, hypotension, migraine, phlebitis, tachycardia, vasodilatation

Respiratory, thoracic and mediastinal disorders: pleural effusion, sinus congestion

Paediatric Patients

VALCYTE has been studied in 179 paediatric solid organ transplant patients who are at risk of developing CMV disease (aged 3 weeks to 16 years) and in 133 neonates with symptomatic congenital CMV disease (aged 2 to 31 days), with duration of ganciclovir exposure ranging from 2 to 200 days (see CLINICAL TRIALS).

Prevention of CMV disease in Solid Organ Transplant (SOT)

Table 8 shows the adverse events (up to 28 days after completion of study treatment) regardless of seriousness and relationship with an incidence of ≥10 % from two clinical trials where solid organ transplant paediatric patients received valganciclovir starting within 10 days post-transplantation until Day 100 post-transplant and where kidney transplant paediatric patients received valganciclovir once daily starting within 10 days post transplantation until Day 200 post-transplant.

The overall safety profile was similar in paediatric patients as compared to adults. However, the rates of certain adverse events, such as, but not limited to, upper respiratory tract infection, pyrexia, abdominal pain and dysuria, that may be characteristic of the paediatric population, were reported in somewhat higher incidence in paediatrics than in adults. Neutropenia was also reported with slightly higher incidence in the two paediatric studies as compared to adults but neutropenia and infectious adverse events were generally not correlated in the paediatric populations.


Table 8 Overview of the common adverse events that occurred on treatment in ≥10 % of the total population in paediatric SOT patients

Paediatric Solid Organ
Transplant Patients
Valganciclovir
100 days
N=63
Valganciclovir
200 days
N=56
System organ class N % N %
Infections and infestations
Urinary tract infection 4 6 19 34
Escherichia Coli urinary tract infection - - 7 13
Upper respiratory tract infection 14 22 19 34
Gastrointestinal disorders
Diarrhoea 20 32 18 32
Constipation 7 11 3 5
Nausea 7 11 5 9
Abdominal pain 4 6 10 18
Vomiting 13 21 7 13
Blood and lymphatic system disorder
Leucopenia 1 2 14 25
Anaemia 9 14 9 16
Neutropenia 8 13 13 23
General disorders and administration site conditions
Pyrexia 15 24 9 16
Renal and urinary disorders
Haematuria 4 6 6 11
Dysuria 1 2 10 18
Nervous system disorders
Tremor 2 3 10 18
Headache 4 6 12 21
Vascular disorders
Hypertension 14 22 9 16
Immune system disorders
Transplant rejection 6 10 3 5

Congenital CMV

The safety profile of valganciclovir and ganciclovir for up to 6 months of treatment was assessed in 133 neonates or infants with symptomatic congenital CMV infection aged from 2 days to 31 days in two studies. Although this data is limited, no safety issues have been identified and safety appears consistent with the known safety profile of valganciclovir/ganciclovir.

In the first study, the primary toxicity associated with ganciclovir was neutropenia with 9 out of 24 subjects (38%) developing Grade 3 or 4 neutropenia while on therapy. Only one subject had to permanently discontinue antiviral treatment, due to neutropenia. Most events were manageable with continuation of antiviral therapy in this study. Growth (head circumference, weight and height) of all neonates, who had growth measurements recorded, increased over time in this non-comparative study.

In the second study, the most frequent treatment-related AEs associated with oral valganciclovir were neutropenia, anaemia, liver function abnormality and diarrhoea, all seen more frequently in the placebo group. The only treatment-related SAEs were neutropenia and anaemia, both seen more frequently in the placebo arm. No statistically or clinically significant differences were observed in the rate of growth (average head circumference, weight and length) over time at each time point between the two treatment groups.

Laboratory Abnormalities

Laboratory abnormalities reported in adult patients receiving VALCYTE until Day 100 post-transplant are listed in Table 9 below. The incidence of laboratory abnormalities was comparable with the extension of prophylaxis up to 200 days in high risk kidney transplant patients.

Laboratory abnormalities reported in paediatric SOT patients are listed in Table 10. The incidence of severe neutropenia (ANC<500/μL) was higher in paediatric kidney patients treated until Day 200 as compared to paediatric patients treated until Day 100 and as compared to adults kidney transplant patients treated until Day 100 or Day 200.


Table 9 Laboratory abnormalities in adult patients

Laboratory abnormalities CMV Retinitis Patients Solid Organ Transplant Patients
Valganciclovir
(n = 370)
Valganciclovir
(n = 244)
Oral ganciclovir
(n = 126)
% % %
Neutropenia (ANC/μL)
< 500 16 5 3
500 - < 750 17 3 2
750 - < 1000 17 5 2
Anaemia (haemoglobin g/dL)
< 6.5 7 1 2
6.5 - < 8.0 10 5 7
8.0 - < 9.5 14 31 25
Thrombocytopenia (platelets/μL)
< 25000 3 0 2
25000 - < 50000 5 1 3
50000 - < 100000 21 18 21
Serum creatinine (mg/dL)
> 2.5 2 14 21
> 1.5 – 2.5 11 45 47

Table 10 Laboratory abnormalities in paediatric SOT transplant patients

Laboratory abnormalities Valganciclovir in Paediatric SOT patients
System organ class Dosing until Day 100
Post-Transplant
n=63
%
Dosing until Day 200
Post-Transplant
n=56
%
Neutropenia (ANC/μL)
<500 5 30
500 - <750 8 7
750 - <1000 5 11
Anaemia (haemoglobin g/dL)
<6.5 0 0
6.5 - <8.0 14 5
8.0 - <9.5 38 29
Thrombocytopenia (platelets/μL)
<25000 0 0
25000 - <50000 10 0
50000 - <100000 3 4
Serum creatinine (mg/dL)
>2.5 2 5
>1.5 – 2.5 11 20

Post-Marketing Experience

Experience with ganciclovir and valganciclovir

As VALCYTE is rapidly and extensively converted to ganciclovir, any adverse events associated with ganciclovir might also occur with VALCYTE. Adverse events from post-marketing spontaneous reports with intravenous and oral ganciclovir not mentioned in any section above, and for which a causal relationship cannot be excluded are listed below..

  • Anaphylaxis
  • Decreased fertility in males

Adverse events that have been reported during the post-marketing period are consistent with those seen in clinical trials with VALCYTE and ganciclovir.

Dosage And Administration

Caution – Strict adherence to dosage recommendations is essential to avoid overdose.

VALCYTE is administered orally, and should be taken with food (see PHARMACOLOGY, Pharmacokinetics, Absorption and Bioavailability).

Valganciclovir is rapidly and extensively converted to the active ingredient ganciclovir. The bioavailability of ganciclovir from VALCYTE is up to 10-fold higher than from oral ganciclovir, therefore the dosage and administration of VALCYTE tablets or powder for oral solution as described below should be closely followed (see PRECAUTIONS and OVERDOSAGE).

The ganciclovir systemic exposure following administration of 900 mg VALCYTE powder for oral solution is equivalent to 900 mg VALCYTE dose administered as two 450 mg tablets.

An oral dosing dispenser with 25 mg graduations up to 500 mg is provided with VALCYTE powder for oral solution. It is recommended that this dispenser is used to measure and administer the VALCYTE dose. The dispenser should not be used to measure or administer any other medicines.

Treatment of CMV Retinitis

Adult Patients

Induction Treatment

For patients with active CMV retinitis, the recommended dosage is 900 mg twice daily for 21 days with food. Prolonged induction treatment may increase the risk of bone marrow toxicity (see PRECAUTIONS, Haematologic).

Maintenance Treatment

Following induction treatment, or in patients with inactive CMV retinitis the recommended dose is 900 mg once daily with food. Patients whose retinitis worsens may repeat induction treatment (see Induction Treatment).

Paediatric Patients

The safety and efficacy of VALCYTE in paediatric patients have not been established in adequate and well-controlled clinical studies.

Prevention of CMV Disease in Transplantation

Adult Patients

For kidney transplant patients, the recommended dose is 900 mg once daily with food, starting within 10 days post- transplantation and continuing until 200 days post-transplantation [see CLINICAL TRIALS, IMPACT Study (Study NT18435)].

For all other solid organ transplant patients, the recommended dose is 900 mg once daily with food, starting within 10 days post-transplantation and continuing until 100 days post-transplantation (see CLINICAL TRIALS, Study PV16000).

Paediatric Patients

In paediatric solid organ transplant patients, (paediatric heart transplant patients from 4 weeks and paediatric kidney transplant patients from 4 months (see CLINICAL TRIALS)), who are at risk of developing CMV disease, the recommended once daily dose of VALCYTE is based on body surface area (BSA) and creatinine clearance (CrCl) derived from Schwartz formula (CrCLS), and is calculated using the equation below:

Paediatric Dose (mg) = 7 x BSA x CrCLS (see Mosteller BSA formula and Schwartz Creatinine Clearance formula below). If the calculated Schwartz creatinine clearance exceeds 150 mL/min/1.73m2, then a maximum value of 150 mL/min/1.73m2 should be used in the equation.


where k = 0.45* for patients aged < 2 years, 0.55 for boys aged 2 to < 13 years and girls aged 2 to 16 years, and 0.7 for boys aged 13 to 16 years. Refer to adult dosing for patients older than 16 years.

The k values provided are based on the Jaffe method of measuring serum creatinine, and may require correction when enzymatic methods are used.

* A lowering of k value may also be necessary for appropriate sub-populations.

For paediatric kidney transplant patients, the recommended once daily mg dose (7x BSA x CrCLS) should start within 10 days post-transplantation and continue until 200 days posttransplantation.

For paediatric patients who have received a solid organ transplant other than kidney, the recommended once daily mg dose (7x BSA x CrCLS) should start within 10 days post transplantation and continue until 100 days post transplantation.

All calculated doses should be rounded to the nearest 25 mg increment for the actual deliverable dose. If the calculated dose exceeds 900 mg, a maximum dose of 900 mg should be administered. The oral solution is the preferred formulation since it provides the ability to administer a dose calculated according to the formula above; however, VALCYTE tablets may be used if the calculated doses are within 10% of available tablet doses and the patient is able to swallow tablets. For example, if the calculated dose is between 405 mg and 495 mg, one 450 mg tablet may be taken.

It is recommended to monitor serum creatinine levels regularly and consider changes in height and body weight and adapt the dose as appropriate during prophylaxis period.

Special Patient Groups

Renal Impairment

Adult Patients

Serum creatinine or creatinine clearance levels should be monitored carefully. Dosage adjustment is required based on creatinine clearance as shown in the Table 9 below (see PHARMACOLOGY, Pharmacokinetics in Special Populations and PRECAUTIONS).


Table 11 VALCYTE tablets and oral powder for solution dose for renally impaired patients

CrCl (mL/min) Induction Dose of tablets Maintenance/ Prevention Dose of tablets Induction Dose of oral powder for solution Maintenance/ Prevention Dose of oral powder for solution
≥ 60 900 mg twice daily 900 mg once daily 900 mg twice daily 900 mg once daily
40 – 59 450 mg twice daily 450 mg once daily 450 mg twice daily 450 mg once daily
25 – 39 450 mg once daily 450 mg every 2 days 450 mg once daily 225 mg once daily
10 – 24 450 mg every 2 days 450 mg twice weekly 225 mg once daily 125 mg once daily
< 10 not recommended not recommended 200 mg (3 times a week after dialysis) 100 mg (3 times a week after dialysis)

* Creatinine clearance can be calculated from serum creatinine by the following formula:


or females = 0.85 x male value

Paediatric Patients

Dosing of paediatric solid organ transplant patients is individualised based on a patient’s renal function and size (see DOSAGE AND ADMINISTRATION).

Patients with severe leukopenia, neutropenia, anaemia, thrombocytopenia and/or pancytopenia

Severe leukopenia, neutropenia, anaemia, thrombocytopenia, pancytopenia, bone marrow depression and aplastic anaemia have been observed in patients treated with VALCYTE (and ganciclovir). Therapy should not be initiated if the absolute neutrophil count is less than 500 cells/μL or the platelet count is less than 25,000/μL or the haemoglobin is less than 8 g/100 mL (see CONTRAINDICATIONS, PRECAUTIONS and ADVERSE EFFECTS).

Method of preparation for powder for oral solution

  1. Tap the bottle to loosen the powder.
  2. Measure 91 mL of purified water in a graduated cylinder.
  3. Remove the child resistant cap and add the water to the bottle. Replace child resistant cap.
  4. Shake the closed bottle until the powder is dissolved.
  5. Remove the child resistant cap and push the bottle adapter into the neck of the bottle.
  6. Replace the child resistant cap and close tightly. This will assure the proper seating of the bottle adapter in the bottle and child resistant status of the cap.
  7. Write the date of preparation and date of expiry of the reconstituted solution on the bottle label (the shelf life of the reconstituted solution is 49 days). The reconstituted solution should be stored in a refrigerator (2 to 8°C).

Handling and Disposal

Caution should be exercised in the handling of VALCYTE tablets and powder for oral solution. VALCYTE tablets should not be broken or crushed. Since valganciclovir is considered a potential teratogen and carcinogen in humans and inhibits spermatogenesis, caution should be observed in handling VALCYTE tablets or the powder for oral solution. Avoid direct contact of broken or crushed tablets, powder or reconstituted solution with skin or mucous membranes. If such contact occurs, wash thoroughly with soap and water, and rinse eyes thoroughly with sterile water, or plain water if sterile water is unavailable.

It is recommended that VALCYTE powder for oral solution be reconstituted by a Pharmacist prior to dispensing to the patient.

The release of medicines into the environment should be minimised. Medicines should not be disposed of via wastewater and disposal through household waste should be avoided. Unused or expired medicine should be returned to a pharmacy for disposal.

Overdosage

Overdose experience with VALCYTE

One adult developed fatal bone marrow depression (medullary aplasia) after several days of dosing that was at least 10-fold greater than recommended for the patient's estimated degree of renal impairment (decreased creatinine clearance).

It is expected that an overdose of valganciclovir could also possibly result in increased renal toxicity (see PRECAUTIONS and DOSAGE AND ADMINISTRATION, Patients with Renal Impairment).

Haemodialysis and hydration may be of benefit in reducing blood plasma levels in patients who receive an overdose of valganciclovir (see PHARMACOLOGY, Pharmacokinetics in Special Populations).

Overdose experience with intravenous ganciclovir

Toxic manifestations seen in animals given very high single intravenous doses of ganciclovir (500 mg/kg) included emesis, hypersalivation, anorexia, bloody diarrhoea, inactivity, cytopenia, elevated liver function test results, elevated serum urea, testicular atrophy, and death.

Reports of overdoses with intravenous ganciclovir have been received from clinical trials and during post-marketing experience. In some of these cases no adverse events were reported. The majority of patients experienced one or more of the following adverse events:

  • Haematological toxicity: pancytopenia, bone marrow depression, medullary aplasia, leukopenia, neutropenia, granulocytopenia
  • Hepatotoxicity: hepatitis, liver function disorder
  • Renal toxicity: worsening of haematuria in a patient with pre-existing renal impairment, acute renal failure, and elevated creatinine.
  • Gastrointestinal toxicity: abdominal pain, diarrhoea, vomiting
  • Neurotoxicity: generalised tremor, convulsion

Treatment of overdose should consist of general supportive measures.

For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).

Presentation And Storage Conditions

VALCYTE Tablets

VALCYTE (valganciclovir HCl) is available as 450 mg pink convex oval tablets with "VGC" on one side and "450" on the other side. Each tablet contains 450 mg valganciclovir. VALCYTE is supplied in bottles of 60 tablets.

VALCYTE tablets should be stored below 30°C.

VALCYTE Powder for Oral Solution

VALCYTE is also available as a powder for oral solution. The powder is white to slightly yellow. The reconstituted solution contains 50 mg/mL valganciclovir and appears clear, colourless to brownish-yellow in colour.

VALCYTE powder for oral solution should be stored below 30°C before reconstitution. When reconstituted, the volume of the solution is 100 mL, providing a minimal usable volume of 88 mL. After reconstitution, the solution should be stored in the refrigerator (2 - 8°C). Do not freeze. The reconstituted solution should be discarded 49 days after reconstitution.

Name And Address Of Sponsor

Roche Products Pty Limited

ABN 70 000 132 865

4-10 Inman Road

Dee Why NSW 2099

AUSTRALIA


Medical enquires: 1800 233 950

Poison Schedule Of The Medicine

Schedule 4 - Prescription Only Medicine –

Date Of First Inclusion In The Australian Register Of Therapeutic Goods (the Artg)

VALCYTE 450mg tablets 17 June 2002


VALCYTE 50 mg/mL powder for oral suspension 24 March 2010

Date Of Most Recent Amendment

8 September 2015