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Summary of Product Characteristics last updated on the eMC: 25/01/2010
SPC Zerit 200 mg Powder for Oral Solution


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1. NAME OF THE MEDICINAL PRODUCT

Zerit 200 mg powder for oral solution


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2. QUALITATIVE AND QUANTITATIVE COMPOSITION

The powder contains 200 mg of stavudine .

The reconstituted solution contains 1 mg of stavudine per ml.

For a full list of excipients, see section 6.1.


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3. PHARMACEUTICAL FORM

Powder for oral solution.

Zerit powder appears as offNON-BREAKING HYPHEN (8209)white to paleNON-BREAKING HYPHEN (8209)pink, gritty powder.


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4. CLINICAL PARTICULARS

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4.1 Therapeutic indications

Zerit is indicated in combination with other antiretroviral medicinal products for the treatment of HIV infected patients.


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4.2 Posology and method of administration

Oral use.

The therapy should be initiated by a doctor experienced in the management of HIV infection (see also section 4.4).

Adults: the recommended dosage is:

Patient weight

Zerit dosage

< 60 kg

GREATER-THAN OR EQUAL TO (8805) 60 kg

30 mg twice daily (every 12 hours)

40 mg twice daily (every 12 hours)

Adolescents, children and infants: the recommended dosage is:

Patient age and/or weight

Zerit dosage

From birth* to 13 days old

At least 14 days old and < 30 kg

GREATER-THAN OR EQUAL TO (8805) 30 kg

0.5 mg/kg twice daily (every 12 hours)

1 mg/kg twice daily (every 12 hours)

adult dosing

*The reduced posology in neonates from 0 to 13 days is based on average study data and may not correspond to invidual variation in kidney maturation. Dosing recommendations are not available for neonates with a gestational age < 37 weeks.

For optimal absorption, Zerit should be taken on an empty stomach (i.e. at least 1 hour prior to meals) but, if this is not possible, it may be taken with a light meal.

Elderly: Zerit has not been specifically investigated in patients over the age of 65.

Instructions for preparation, see section 6.6.

Dose adjustments

Peripheral neuropathy: if symptoms of peripheral neuropathy develop (usually characterised by persistent numbness, tingling, or pain in the feet and/or hands) (see section 4.4), patients should be switched to an alternative treatment regimen, if appropriate. In the rare cases when this is inappropriate, dose reduction of stavudine may be considered, while the symptoms of peripheral neuropathy are under close monitoring and satisfactory virological suppression is maintained.

The possible benefits of a dose reduction should be balanced in each case against the risks - which may result from this measure (lower intracellular concentrations).

Hepatic impairment: no initial dosage adjustment is necessary.

Renal impairment: the following dosages are recommended:

 

 

Zerit dosage (according to creatinine clearance)

Patient weight

26NON-BREAKING HYPHEN (8209)50 ml/min

LESS-THAN OR EQUAL TO (8804) 25 ml/min

(including dialysis dependence*)

< 60 kg

15 mg twice daily

15 mg every 24 hours

GREATER-THAN OR EQUAL TO (8805) 60 kg

20 mg twice daily

20 mg every 24 hours

* Patients on haemodialysis should take Zerit after the completion of haemodialysis, and at the same time on nonNON-BREAKING HYPHEN (8209)dialysis days.

Since urinary excretion is also a major route of elimination of stavudine in paediatric patients, the clearance of stavudine may be altered in paediatric patients with renal impairment. Although there are insufficient data to recommend a specific dosage adjustment of Zerit in this patient population, a reduction in the dose and/or an increase in the interval between doses proportional to the reduction for adults should be considered.


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4.3 Contraindications

Hypersensitivity to stavudine or to any of the excipients.


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4.4 Special warnings and precautions for use

Peripheral neuropathy: patients with a history of peripheral neuropathy are at increased risk for development of neuropathy. If Zerit must be administered in this setting, careful clinical monitoring is essential. Symptoms of peripheral neuropathy are characterised by persistent numbness, tingling, or pain in the feet and/or hands.

Pancreatitis: patients with a history of pancreatitis had an incidence of approximately 5% on Zerit, as compared to approximately 2% in patients without such a history. Patients with a high risk of pancreatitis or those receiving products known to be associated with pancreatitis should be closely followed for symptoms of this condition.

Lactic acidosis: lactic acidosis, usually associated with hepatomegaly and hepatic steatosis has been reported with the use of nucleoside reverse transcriptase inhibitors (NRTIs). Early symptoms (symptomatic hyperlactatemia) include benign digestive symptoms (nausea, vomiting and abdominal pain), nonNON-BREAKING HYPHEN (8209)specific malaise, loss of appetite, weight loss, respiratory symptoms (rapid and/or deep breathing) or neurological symptoms (including motor weakness). Lactic acidosis has a high mortality and may be associated with pancreatitis, liver failure, renal failure, or motor paralysis.

Lactic acidosis generally occurred after a few or several months of treatment.

Treatment with NRTIs should be discontinued if there is symptomatic hyperlactatemia and metabolic/lactic acidosis, progressive hepatomegaly, or rapidly elevating aminotransferase levels. Caution should be exercised when administering NRTIs to any patient (particularly obese women) with hepatomegaly, hepatitis or other known risk factors for liver disease and hepatic steatosis (including certain medicinal products and alcohol). Patients coNON-BREAKING HYPHEN (8209)infected with hepatitis C and treated with alpha interferon and ribavirin may constitute a special risk.

Patients at increased risk should be followed closely (see also section 4.6).

Liver disease: hepatitis or liver failure, which was fatal in some cases, has been reported. The safety and efficacy of stavudine has not been established in patients with significant underlying liver disorders. Patients with chronic hepatitis B or C and treated with combination antiretroviral therapy are at an increased risk of severe and potentially fatal hepatic adverse events. In case of concomitant antiviral therapy for hepatitis B or C, please refer also to the relevant product information for these medicinal products.

Patients with preNON-BREAKING HYPHEN (8209)existing liver dysfunction including chronic active hepatitis have an increased frequency of liver function abnormalities during combination antiretroviral therapy and should be monitored according to standard practice. If there is evidence of worsening liver disease in such patients, interruption or discontinuation of treatment must be considered.

In the event of rapidly elevating transaminase levels (ALT/AST, > 5 times upper limit of normal, ULN), discontinuation of Zerit and any potentially hepatotoxic medicinal products should be considered.

Immune reactivation syndrome: in HIVNON-BREAKING HYPHEN (8209)infected patients with severe immune deficiency at the time of institution of combination antiretroviral therapy (CART), an inflammatory reaction to asymptomatic or residual opportunistic pathogens may arise and cause serious clinical conditions, or aggravation of symptoms. Typically, such reactions have been observed within the first few weeks or months of initiation of CART. Relevant examples are cytomegalovirus retinitis, generalised and/or focal mycobacterial infections, and Pneumocystis carinii pneumonia. Any inflammatory symptoms should be evaluated and treatment instituted when necessary.

Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated with the redistribution of body fat (lipodystrophy) in HIV patients. The longNON-BREAKING HYPHEN (8209)term consequences of these events are currently unknown. Knowledge about the mechanism is incomplete. A connection between visceral lipomatosis and Protease Inhibitors and lipoatrophy and NRTIs has been hypothesised. A higher risk of lipodystrophy has been associated with individual factors such as older age, and with drug related factors such as longer duration of antiretroviral treatment and associated metabolic disturbances. Clinical examination should include evaluation for physical signs of fat redistribution. Consideration should be given to the measurement of fasting serum lipids and blood glucose. Lipid disorders should be managed as clinically appropriate (see section 4.8).

There is evidence that mitochondrial DNA toxicity may be associated with specific features of lipoatrophy in patients using stavudine. This should be taken into account when considering initiation of combination antiretroviral therapy with stavudine.

Osteonecrosis: although the etiology is considered to be multifactorial (including corticosteroid use, alcohol consumption, severe immunosuppression, higher body mass index), cases of osteonecrosis have been reported particularly in patients with advanced HIV-disease and/or long-term exposure to combination antiretroviral therapy (CART). Patients should be advised to seek medical advice if they experience joint aches and pain, joint stiffness or difficulty in movement.

Elderly: Zerit has not been specifically investigated in patients over the age of 65.

Diabetic patients: the reconstituted powder for oral solution contains 50 mg sucrose per ml of reconstituted solution.

Infants under the age of 3 months: safety data is available from clinical trials up to 6 weeks of treatment in 179 newborns and infants < 3 months of age (see section 4.6).

Special consideration should be given to the antiretroviral treatment history and the resistance profile of the HIV strain of the mother.

Mitochondrial dysfunction: nucleoside and nucleotide analogues have been demonstrated in vitro and in vivo to cause a variable degree of mitochondrial damage. There have been reports of mitochondrial dysfunction in HIVNON-BREAKING HYPHEN (8209)negative infants exposed in utero and/or postNON-BREAKING HYPHEN (8209)natally to nucleoside analogues (see also section 4.8). The main adverse events reported are haematological disorders (anaemia, neutropenia), metabolic disorders (hyperlactatemia, hyperlipasemia). These events are often transitory. Some lateNON-BREAKING HYPHEN (8209)onset neurological disorders have been reported (hypertonia, convulsion, abnormal behaviour). Whether the neurological disorders are transient or permanent is currently unknown. Any child exposed in utero to nucleoside and nucleotide analogues, even HIVNON-BREAKING HYPHEN (8209)negative children, should have clinical and laboratory followNON-BREAKING HYPHEN (8209)up and should be fully investigated for possible mitochondrial dysfunction in case of relevant signs or symptoms. These findings do not affect current national recommendations to use antiretroviral therapy in pregnant women to prevent vertical transmission of HIV.

Not recommended combinations: pancreatitis (fatal and nonfatal) and peripheral neuropathy (severe in some cases) have been reported in HIV infected patients receiving stavudine in association with hydroxyurea and didanosine. Hepatotoxicity and hepatic failure resulting in death were reported during postmarketing surveillance in HIV infected patients treated with antiretroviral agents and hydroxyurea; fatal hepatic events were reported most often in patients treated with stavudine, hydroxyurea and didanosine. Hence, hydroxyurea should not be used in the treatment of HIV infection.


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4.5 Interaction with other medicinal products and other forms of interaction

Interaction studies have only been performed in adults

Since stavudine is actively secreted by the renal tubules, interactions with other actively secreted medicinal products are possible, e.g. with trimethoprim. No clinically relevant pharmacokinetic interaction has, however, been seen with lamivudine.

Zidovudine and stavudine are phosphorylated by the cellular enzyme (thymidine kinase), which preferentially phosphorylates zidovudine, thereby decreasing the phosphorylation of stavudine to its active triphosphate form. Zidovudine is therefore not recommended to be used in combination with stavudine.

In vitro studies indicate that the activation of stavudine is inhibited by doxorubicin and ribavirin but not by other medicinal products used in HIV infection which are similarly phosphorylated, (e.g. didanosine, zalcitabine, ganciclovir and foscarnet) therefore, coadministration of stavudine with either doxorubicin or ribavirin should be undertaken with caution. Stavudine's influence on the phosphorylation kinetics of nucleoside analogues other than zidovudine has not been investigated.

Clinically significant interactions of stavudine or stavudine plus didanosine with nelfinavir have not been observed.

Stavudine does not inhibit the major cytochrome P450 isoforms CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4; therefore, it is unlikely that clinically significant drug interactions will occur with drugs metabolised through these pathways.

Because stavudine is not proteinNON-BREAKING HYPHEN (8209)bound, it is not expected to affect the pharmacokinetics of proteinNON-BREAKING HYPHEN (8209)bound drugs.

There have been no formal interaction studies with other medicinal products.


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4.6 Pregnancy and lactation

Zerit should not be used during pregnancy unless clearly necessary.

Clinical experience in pregnant women is limited, but congenital anomalies and abortions have been reported.

In study AI455NON-BREAKING HYPHEN (8209)094, performed in SouthNON-BREAKING HYPHEN (8209)Africa, 362 motherNON-BREAKING HYPHEN (8209)infant pairs were included in a prevention of motherNON-BREAKING HYPHEN (8209)toNON-BREAKING HYPHEN (8209)childNON-BREAKING HYPHEN (8209)transmission study. Treatment naive pregnant women were enrolled into the study at gestation week 34NON-BREAKING HYPHEN (8209)36 and given antiretroviral treatment until delivery. Antiretroviral prophylaxis, the same medications as given to the mother, was given to the newNON-BREAKING HYPHEN (8209)born infant within 36 hours of delivery and continued for 6 weeks. In the stavudine containing arms, the neonates were treated for 6 weeks with stavudine 1 mg/kg BID. The followNON-BREAKING HYPHEN (8209)up time was up to 24 weeks of age.

The motherNON-BREAKING HYPHEN (8209)infant pairs were randomised to receive either stavudine (N= 91), didanosine (N= 94), stavudine + didanosine (N= 88) or zidovudine (N= 89).

95% Confidence intervals for the motherNON-BREAKING HYPHEN (8209)toNON-BREAKING HYPHEN (8209)childNON-BREAKING HYPHEN (8209)transmission rates were 5.4NON-BREAKING HYPHEN (8209)19.3% (stavudine), 5.2NON-BREAKING HYPHEN (8209)18.7% (didanosine); 1.3NON-BREAKING HYPHEN (8209)11.2% (stavudine + didanosine); and 1.9NON-BREAKING HYPHEN (8209)12.6% for zidovudine.

Preliminary safety data from this study (see also section 4.8), showed an increased infant mortality in the stavudine + didanosine (10%) treatment group compared to the stavudine (2%), didanosine (3%) or zidovudine (6%) groups, with a higher incidence of stillbirths in the stavudine + didanosine group. Data on lactic acid in serum were not collected in this study.

However, lactic acidosis (see section 4.4), sometimes fatal, has been reported in pregnant women who received the combination of didanosine and stavudine with or without other antiNON-BREAKING HYPHEN (8209)retroviral treatment. EmbryoNON-BREAKING HYPHEN (8209)foetal toxicities were seen only at high exposure levels in animals. Preclinical studies showed placental transfer of stavudine (see section 5.3). Until additional data become available, Zerit should be given during pregnancy only after special consideration; there is insufficient information to recommend Zerit for prevention of motherNON-BREAKING HYPHEN (8209)toNON-BREAKING HYPHEN (8209)child transmission of HIV. Furthermore, the combination of stavudine and didanosine should be used with caution during pregnancy and is recommended only if the potential benefit clearly outweighs the potential risk.

It is recommended that HIV infected women should not breastNON-BREAKING HYPHEN (8209)feed under any circumstances in order to avoid transmission of HIV.

The data available on stavudine excretion into human breast milk are insufficient to assess the risk to the infant. Studies in lactating rats showed that stavudine is excreted in breast milk. Therefore, mothers should be instructed to discontinue breastNON-BREAKING HYPHEN (8209)feeding prior to receiving Zerit.


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4.7 Effects on ability to drive and use machines

No studies on the effects on the ability to drive and use machines have been performed.

Based on the pharmacodynamic properties of stavudine it is unlikely that Zerit affects the ability to drive or operate machinery.


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4.8 Undesirable effects

Adults: extensive safety experience is available for Zerit used as monotherapy and in combination regimens. Many of the serious undesirable effects with stavudine were consistent with the course of HIV infection or with the side effects of concomitant therapies.

Peripheral neuropathy: In combination studies of Zerit with lamivudine plus efavirenz, the frequency of peripheral neurologic symptoms was 19% (6% for moderate to severe) with a rate of discontinuation due to neuropathy of 2%. DoseNON-BREAKING HYPHEN (8209)related peripheral neuropathy occurred in monotherapy trials with Zerit (see sections 4.2 and 4.4). The patients usually experienced resolution of symptoms after dose reduction or interruption.

Pancreatitis: pancreatitis, occasionally fatal, has been reported in up to 2NON-BREAKING HYPHEN (8209)3% of patients enrolled in monotherapy clinical studies (see section 4.4). Pancreatitis was reported in < 1% of patients in combination therapy studies with Zerit.

Lactic acidosis: cases of lactic acidosis, sometimes fatal, usually associated with severe hepatomegaly and hepatic steatosis, have been reported with the use of nucleoside analogues (see section 4.4).

Motor weakness has been reported rarely in patients receiving combination antiretroviral therapy including Zerit. Most of these cases occurred in the setting of symptomatic hyperlactatemia or lactic acidosis syndrome (see section 4.4). The evolution of motor weakness may mimic the clinical presentation of Guillain-Barré syndrome (including respiratory failure). Symptoms may continue or worsen following discontinuation of therapy.

Hepatitis or liver failure, which was fatal in some cases, has been reported with the use of stavudine and with other nucleoside analogues (see section 4.4).

Immune reactivation syndrome: in HIVNON-BREAKING HYPHEN (8209)infected patients with severe immune deficiency at the time of initiation of combination antiretroviral therapy (CART), an inflammatory reaction to asymptomatic or residual opportunistic infections may arise (see section 4.4).

Lipodystrophy and metabolic abnormalities: combination antiretroviral therapy has been associated with redistribution of body fat (lipodystrophy) in HIV patients including the loss of peripheral and facial subcutaneous fat, increased intraNON-BREAKING HYPHEN (8209)abdominal and visceral fat, breast hypertrophy and dorsocervical fat accumulation (buffalo hump).

Combination antiretroviral therapy has been associated with metabolic abnormalities such as hypertriglyceridaemia, hypercholesterolaemia, insulin resistance, hyperglycaemia and hyperlactataemia (see section 4.4).

Osteonecrosis: cases of osteonecrosis have been reported, particularly in patients with generally acknowledged risk factors, advanced HIV disease or long-term exposure to combination antiretroviral therapy (CART). The frequency of this is unknown (see section 4.4).

The frequency of adverse reactions listed below is defined using the following convention:

very common (GREATER-THAN OR EQUAL TO (8805) 1/10); common (GREATER-THAN OR EQUAL TO (8805) 1/100, < 1/10); uncommon (GREATER-THAN OR EQUAL TO (8805) 1/1,000, < 1/100); rare (GREATER-THAN OR EQUAL TO (8805) 1/10,000, < 1/1,000); very rare (< 1/10,000). Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.

Undesirable effects (moderate to severe) were reported from 467 patients treated with Zerit in combination with lamivudine and efavirenz in two randomised clinical trials and an ongoing longNON-BREAKING HYPHEN (8209)term followNON-BREAKING HYPHEN (8209)up study (total followNON-BREAKING HYPHEN (8209)up: median 56 weeks ranging up to 119 weeks). The following undesirable effects considered possibly related to study regimen based on investigators' attribution, have been identified:

Endocrine disorders:

uncommon: gynaecomastia

 

Gastrointestinal disorders:

common: diarrhoea, abdominal pain, nausea, dyspepsia

uncommon: pancreatitis, vomiting

 

General disorders and administration site conditions:

common: fatigue

uncommon: asthenia

 

Hepatobiliary disorders:

uncommon: hepatitis or jaundice

 

Metabolism and nutrition disorders:

common: lipoatrophy,* lipodystrophy

uncommon: lactic acidosis (in some cases involving motor weakness), anorexia

 

Musculoskeletal and connective tissue disorders:

uncommon: arthralgia, myalgia

 

 

Nervous system disorders:

common: peripheral neurologic symptoms including peripheral neuropathy, paresthesia, and peripheral neuritis; dizziness; abnormal dreams; headache, insomnia; abnormal thinking; somnolence

 

Psychiatric disorders:

common: depression

uncommon: anxiety, emotional lability

 

Skin and subcutaneous tissue disorders:

common: rash, pruritus

uncommon: urticaria

*Lipoatrophy was observed in a long-term follow-up study of stavudine in combination with lamivudine and efavirenz (total follow-up: median 148 weeks ranging up to 207 weeks).

Discontinuation due to undesirable events was 7% for the patients treated with Zerit.

Laboratory abnormalities reported in these two trials and an ongoing followNON-BREAKING HYPHEN (8209)up study included elevations of ALT (> 5 x ULN) in 3%, of AST (> 5 x ULN) in 3%, of lipase (GREATER-THAN OR EQUAL TO (8805) 2.1 ULN) in 3% of the patients in the Zerit group. Neutropenia (< 750 cells/mm3) was reported in 5%, thrombocytopenia (platelets < 50,000/mm3) in 2%, and low haemoglobin (< 8 g/dl) in < 1% of patients receiving Zerit.

Macrocytosis was not evaluated in these trials, but was found to be associated with Zerit in an earlier trial (MCV > 112 fl occurred in 30% of patients treated with Zerit).

Adolescents, children and infants: undesirable effects and serious laboratory abnormalities reported to occur in paediatric patients ranging in age from birth through adolescence who received stavudine in clinical studies were generally similar in type and frequency to those seen in adults. However, clinically significant peripheral neuropathy is less frequent. These studies include ACTG 240, where 105 paediatric patients ages 3 months to 6 years received Zerit 2 mg/kg/day for a median of 6.4 months; a controlled clinical trial where 185 newborns received Zerit 2 mg/kg/day either alone or in combination with didanosine from birth through 6 weeks of age; and a clinical trial where 8 newborns received Zerit 2 mg/kg/day in combination with didanosine and nelfinavir from birth through 4 weeks of age.

In study AI455NON-BREAKING HYPHEN (8209)094 (see also section 4.6), the safety followNON-BREAKING HYPHEN (8209)up period was restricted to only six months, which may be insufficient to capture longNON-BREAKING HYPHEN (8209)term data on neurological adverse events and mitochondrial toxicity. Relevant grade 3NON-BREAKING HYPHEN (8209)4 laboratory abnormalities in the 91 stavudine treated infants were low neutrophils in 7%, low hemoglobin in 1%, ALT increase in 1% and no lipase abnormality. Data on lactic acid in serum were not collected. No notable differences in the frequency of adverse drug reactions were seen between treatment groups. There was, however, an increased infant mortality in the stavudine + didanosine (10%) treatment group compared to the stavudine (2%), didanosine (3%) or zidovudine (6%) groups, with a higher incidence of stillbirths in the stavudine + didanosine group.

Postmarketing

The following events have been reported spontaneously during postmarketing experience:

Blood and lymphatic system disorders:

 

Not known: anaemia, thrombocytopenia, neutropenia

Metabolic and nutrition disorders:

 

Common: asymptomatic hyperlactatemia,

Not known: lactic acidosis, diabetes mellitus, hyperglycaemia

Hepatobiliary disorders:

 

Not known: liver failure, hepatitis and hepatic steatosis

Nervous system disorders:

 

Not known: motor weakness (most often reported in the setting of symptomatic hyperlactatemia or lactic acidosis syndrome)

Mitochondrial dysfunction: review of the postmarketing safety database shows that adverse events indicative of mitochondrial dysfunction have been reported in the neonate and infant population exposed to one or more nucleoside analogues (see also section 4.4). The HIV status for the newborns and infants LESS-THAN OR EQUAL TO (8804) 3 months of age was negative, for older infants it tended to be positive. The profile of the adverse events for newborns and infants LESS-THAN OR EQUAL TO (8804) 3 months of age showed increases in lactic acid levels, neutropenia, anaemia, thrombocytopenia, hepatic transaminase increases and increased lipids, including hypertriglyceridaemia. The number of reports in older infants was too small to identify a pattern.


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4.9 Overdose

Experience in adults treated with up to 12 times the recommended daily dosage revealed no acute toxicity. Complications of chronic overdosage could include peripheral neuropathy and hepatic dysfunction. The mean haemodialysis clearance of stavudine is 120 ml/min. The contribution of this to the total elimination in an overdose situation is unknown. It is not known whether stavudine is removed by peritoneal dialysis.


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5. PHARMACOLOGICAL PROPERTIES

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5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Nucleoside reverse transcriptase inhibitor, ATC code: J05AF04

Mechanism of action: stavudine, a thymidine analogue, is phosphorylated by cellular kinases to stavudine triphosphate which inhibits HIV reverse transcriptase by competing with the natural substrate, thymidine triphosphate. It also inhibits viral DNA synthesis by causing DNA chain termination due to a lack of the 3'NON-BREAKING HYPHEN (8209)hydroxyl group necessary for DNA elongation. Cellular DNA polymerase γ is also sensitive to inhibition by stavudine triphosphate, while cellular polymerases α and β are inhibited at concentrations 4,000NON-BREAKING HYPHEN (8209)fold and 40NON-BREAKING HYPHEN (8209)fold higher, respectively, than that needed to inhibit HIV reverse transcriptase.

Resistance: stavudine treatment can select for and/or maintain thymidine analogue mutations (TAMs) associated with zidovudine resistance. The decrease of susceptibility in vitro is subtle requiring two or more TAMs (generally M41L and T215Y) before stavudine susceptibility is decreased (>1.5 fold).

These TAMs are seen at a similar frequency with stavudine and zidovudine in virological treatment. The clinical relevance of these findings suggest that stavudine should be generally avoided in the presence of TAMs, especially M41L and T215Y.

The activity of stavudine is also affected by multi-drug resistance associated mutations such as Q151M. In addition, K65R has been reported in patients receiving stavudine/didanosine or stavudine/lamivudine, but not in patients receiving stavudine monotherapy. V75T is selected in vitro by stavudine and reduces susceptibility to stavudine by 2NON-BREAKING HYPHEN (8209)fold. It occurs in ~1% of patients receiving stavudine.

Clinical efficacy

Zerit has been studied in combination with other antiretroviral agents, e.g. didanosine, lamivudine, ritonavir, indinavir, saquinavir, efavirenz, and nelfinavir.

In antiretroviral naive patients

Study AI455NON-BREAKING HYPHEN (8209)099 was a 48NON-BREAKING HYPHEN (8209)week, randomised, doubleNON-BREAKING HYPHEN (8209)blind study withZerit (40 mg twice daily), in combination with lamivudine (150 mg twice daily) plus efavirenz (600 mg once daily), in 391 treatmentNON-BREAKING HYPHEN (8209)naive patients, with a median CD4 cell count of 272 cells/mm3 (range 61 to 1,215 cells/mm3) and a median plasma HIVNON-BREAKING HYPHEN (8209)1 RNA of 4.80 log10 copies/ml (range 2.6 to 5.9 log 10 copies/ml) at baseline. Patients were primarily males (70%) and nonNON-BREAKING HYPHEN (8209)white (58%) with a median age of 33 years (range 18 to 68 years).

Study AI455NON-BREAKING HYPHEN (8209)096 was a 48NON-BREAKING HYPHEN (8209)week, randomised, doubleNON-BREAKING HYPHEN (8209)blind study with Zerit (40 mg twice daily), in combination with lamivudine (150 mg twice daily) plus efavirenz (600 mg once daily), in 76 treatmentNON-BREAKING HYPHEN (8209)naive patients, with a median CD4 cell count of 261 cells/mm3 (range 63 to 962 cells/mm3) and a median plasma HIVNON-BREAKING HYPHEN (8209)1 RNA of 4.63 log10 copies/ml (range 3.0 to 5.9 log10 copies/ml) at baseline. Patients were primarily males (76%) and white (66%) with a median age of 34 years (range 22 to 67 years).

The results of AI455-099 and AI455-096 are presented in Table 1. Both studies were designed to compare two formulations of Zerit, one of which was the marketed formulation dosed as currently approved in product labelling. Only the data from the marketed formulation are presented.

Table 1: Efficacy Outcomes at Week 48 (Studies AI455-099 and AI455-096)

 

AI455-099

AI455-096

 

Parameter

Zerit + lamivudine + efavirenz

n=391

Zerit + lamivudine + efavirenz

n=76

HIV RNA < 400 copies/ml, treatment response, %

All patients

73

66

HIV RNA < 50 copies/ml, treatment response, %

All patients

55

38

HIV RNA Mean Change from Baseline, log 10 copies/ml

All patients

-2.83 (n=321a )

-2.64 (n=58)

CD4 Mean Change from Baseline, cells/mm3

All patients

182 (n=314)

195 (n=55)

a Number of patients evaluable.

The use of stavudine in adolescents, children and infants is supported by pharmacokinetic and safety data in paediatric patients (see also sections 4.8 and 5.2).


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5.2 Pharmacokinetic properties

Adults

Absorption: the absolute bioavailability is 86±18%. After multiple oral administration of 0.5NON-BREAKING HYPHEN (8209)0.67 mg/kg doses, a Cmax value of 810±175 ng/ml was obtained. Cmax and AUC increased proportionally with dose in the dose ranges, intravenous 0.0625NON-BREAKING HYPHEN (8209)0.75 mg/kg, and oral 0.033NON-BREAKING HYPHEN (8209)4.0 mg/kg.

In eight patients receiving 40 mg twice daily in the fasted state, steadyNON-BREAKING HYPHEN (8209)state AUC0NON-BREAKING HYPHEN (8209)12h was 1284±227 ngDOT OPERATOR (8901)h/ml (18%) (mean ± SD [% CV]), Cmax was 536±146 ng/ml (27%), and Cmin was 9±8 ng/ml (89%). A study in asymptomatic patients demonstrated that systemic exposure is similar while Cmax is lower and Tmax is prolonged when stavudine is administered with a standardised, highNON-BREAKING HYPHEN (8209)fat meal compared with fasting conditions. The clinical significance of this is unknown.

Distribution: the apparent volume of distribution at steady state is 46±21 l. It was not possible to detect stavudine in cerebrospinal fluid until at least 2 hours after oral administration. Four hours after administration, the CSF/plasma ratio was 0.39±0.06. No significant accumulation of stavudine is observed with repeated administration every 6, 8, or 12 hours.

Binding of stavudine to serum proteins was negligible over the concentration range of 0.01 to 11.4 µg/ml. Stavudine distributes equally between red blood cells and plasma.

Metabolism: Unchanged stavudine was the major drug-related component in total plasma radioactivity circulating after an oral 80 mg dose of 14C-stavudine in health subjects. The AUC(inf) for stavudine was 61% of the AUC(inf) of the total circulating radioactivity. Metabolites include oxidised stavudine, glucuronide conjugates of stavudine and its oxidised metabolite, and an N-acetylcysteine conjugate of the ribose after glycosidic cleavage, suggesting that thymine is also a metabolite of stavudine.

Elimination: following an oral 80-mg dose of 14C-stavudine to healthy subjects, approximately 95% and 3% of the total radioactivity was recovered in urine and faeces, respectively. Approximately 70% of the orally administered stavudine dose was excreted as an unchanged drug in urine. Mean renal clearance of the parent compound is approximately 272 mL/min, accounting for approximately 67% of the apparent oral clearance, indicating active tubular secretion in addition to glomerular filtration.

In HIV-infected patients, total clearance of stavudine is 594±164 ml/min, and renal clearance is 237±98 ml/min. The total clearance of stavudine appears to be higher in HIV-infected patients, while the renal clearance is similar between healthy subjects and HIV-infected patients. The mechanism and clinical significance of this difference are unknown. After intravenous administration, 42% (range: 13% to 87%) of dose is excreted unchanged in the urine. The corresponding values after oral single and multiple dose administration are 35% (range: 8% to 72%) and 40% (range: 12% to 82%), respectively. The mean terminal elimination halfNON-BREAKING HYPHEN (8209)life of stavudine is 1.3 to 2.3 hours following single or multiple doses, and is independent of dose. In vitro, stavudine triphosphate has an intracellular halfNON-BREAKING HYPHEN (8209)life of 3.5 hours in CEM TNON-BREAKING HYPHEN (8209)cells (a human TNON-BREAKING HYPHEN (8209)lymphoblastoid cell line) and peripheral blood mononuclear cells, supporting twice daily dosing.

The pharmacokinetics of stavudine was independent of time, since the ratio between AUC(ss) at steady state and the AUC(0NON-BREAKING HYPHEN (8209)t) after the first dose was approximately 1. IntraNON-BREAKING HYPHEN (8209)and interindividual variation in pharmacokinetic characteristics of stavudine is low, approximately 15% and 25%, respectively, after oral administration.

Special Populations

Adolescents, children and infants: total exposure to stavudine was comparable between adolescents, children and infants GREATER-THAN OR EQUAL TO (8805) 14 days receiving the 2 mg/kg/day dose and adults receiving 1 mg/kg/day. Apparent oral clearance was approximately 14 ml/min/kg for infants ages 5 weeks to 15 years, 12 ml/min/kg for infants ages 14 to 28 days, and 5 ml/min/kg for infants on the day of birth. Two to three hours postNON-BREAKING HYPHEN (8209)dose, CSF/plasma ratios of stavudine ranged from 16% to 125% (mean of 59%±35%).

Renal impairment: the clearance of stavudine decreases as creatinine clearance decreases; therefore, it is recommended that the dosage of Zerit be adjusted in patients with reduced renal function (see section 4.2).

Hepatic impairment: stavudine pharmacokinetics in patients with hepatic impairment were similar to those in patients with normal hepatic function.


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5.3 Preclinical safety data

Animal data showed embryoNON-BREAKING HYPHEN (8209)foetal toxicity at very high exposure levels. An ex vivo study using a term human placenta model demonstrated that stavudine reaches the foetal circulation by simple diffusion. A rat study also showed placental transfer of stavudine, with the foetal tissue concentration approximately 50% of the maternal plasma concentration.

Stavudine was genotoxic in in vitro tests in human lymphocytes possessing triphosphorylating activity (in which no noNON-BREAKING HYPHEN (8209)effect level was established), in mouse fibroblasts, and in an in vivo test for chromosomal aberrations. Similar effects have been observed with other nucleoside analogues.

Stavudine was carcinogenic in mice (liver tumours) and rats (liver tumours: cholangiocellular, hepatocellular, mixed hepatocholangiocellular, and/or vascular; and urinary bladder carcinomas) at very high exposure levels. No carcinogenicity was noted at doses of 400 mg/kg/day in mice and 600 mg/kg/day in rats, corresponding to exposures ~ 39 and 168 times the expected human exposure, respectively, suggesting an insignificant carcinogenic potential of stavudine in clinical therapy.


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6. PHARMACEUTICAL PARTICULARS

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6.1 List of excipients

Cherry flavour

Methylhydroxybenzoate (E218)

Propylhydroxybenzoate (E216)

Silicon dioxide

Simethicone

Sodium carmellose

Sorbic acid

Stearate emulsifiers

Sucrose


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6.2 Incompatibilities

Not applicable.


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6.3 Shelf life

2 years.

After reconstitution, the prepared oral solution is stable for 30 days in a refrigerator (2°C-8°C).


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6.4 Special precautions for storage

Do not store the dry powder above 30°C.

After reconstitution, store in a refrigerator ( 2°CNON-BREAKING HYPHEN (8209)8°C). For storage conditions of the reconstituted medicinal product, see section 6.3.

Store in the original package.

Keep the bottle tightly closed.


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6.5 Nature and contents of container

HDPE bottle with child resistant screw cap, fill mark (200 ml of solution after reconstitution) and measuring cup.


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6.6 Special precautions for disposal and other handling

Instructions for preparation

Reconstitute with water to a 200 ml deliverable volume solution (stavudine concentration of 1 mg/ml):

add 202 ml of water to the original bottle (when the patient makes up the solution, they should be instructed to fill to the mark). Replace the cap.

Shake the bottle well until the powder dissolves completely. The solution appears as a colourless to slightly pink, hazy solution.

Dispense the solution with the measuring cup provided, or for doses less than 10 ml, dispense with a syringe. The patient should be instructed to shake the bottle well prior to measuring each dose.

Disposal

Any unused product or waste material should be disposed of in accordance with local requirements.


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7. MARKETING AUTHORISATION HOLDER

BRISTOLNON-BREAKING HYPHEN (8209)MYERS SQUIBB PHARMA EEIG

Uxbridge Business Park

Sanderson Road

Uxbridge UB8 1DH

United Kingdom


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8. MARKETING AUTHORISATION NUMBER(S)

EU/1/96/009/009


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9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION

Date of first authorisation: 08 May 1996

Date of last renewal: 08 June 2006


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10. DATE OF REVISION OF THE TEXT

October 2009

Detailed information on this product is available on the website of the European Medicines Agency (EMEA) http://www.emea.europa.eu/.



More information about this product

Link to this document from your website: http://emc.medicines.org.uk/medicine/362/SPC/Zerit 200 mg Powder for Oral Solution/


Active Ingredients/Generics

 
   stavudine


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