Risk Summary
There are no adequate and well controlled studies with Zavesca in pregnant women. However, animal reproduction studies have been conducted for Zavesca. In these animal studies, decreased live births and decreased fetal weight were observed in rats orally dosed with miglustat prior to mating and during organogenesis at doses with exposures at and greater than 2 times the human therapeutic systemic exposure. Maternal death and decreased body weight gain were observed in rabbits orally dosed with miglustat during organogenesis at doses with exposures less than the human therapeutic systemic exposure. Zavesca should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Clinical Considerations
Disease-associated maternal and embryo-fetal risk
Women with Type 1 Gaucher disease have an increased risk of spontaneous abortion, especially if disease symptoms are not treated and controlled pre-conception and during a pregnancy. Pregnancy may exacerbate existing Type 1 Gaucher disease symptoms or result in new disease manifestations. Type 1 Gaucher disease manifestations may lead to adverse pregnancy outcomes including, hepatosplenomegaly which can interfere with the normal growth of a pregnancy and thrombocytopenia which can lead to increased bleeding and possible hemorrhage.
Data
Animal Data
In female rats given miglustat by oral gavage at doses of 20, 60, 180 mg/kg/day beginning 14 days before mating and continuing through gestation day 17 (organogenesis), decreased live births including complete litter loss and decreased fetal weight were observed in the mid-dose and high-dose groups (systemic exposures ≥2 times the human therapeutic systemic exposure, based on body surface area comparison). In pregnant rats given miglustat by oral gavage at doses of 20, 60, 180 mg/kg/day from gestation day 6 through lactation (postpartum day 20), dystocia and delayed parturition were observed in the mid- and high-dose groups (systemic exposure ≥2 times the human therapeutic systemic exposure, based on body surface comparison). In addition, decreased live births and pup body weights were observed at >20 mg/kg/day (systemic exposures less than the human therapeutic systemic exposure, based on body surface area comparison).
In pregnant rabbits given miglustat by oral gavage at doses of 15, 30, 45 mg/kg/day during gestation days 6-18 (organogenesis), maternal death and decreased body weight gain were observed at 15 mg/kg/day (systemic exposures less than the human therapeutic systemic exposure, based on body surface area comparisons).
A pre and postnatal development study in rats showed no evidence of any adverse effect on pre and postnatal development at oral doses up to 180 mg/kg/day (about 6 times the recommended daily human dose of 5 mg/kg based on body surface area).
Infertility
No effect on sperm concentration, motility, or morphology was seen in 7 healthy adult men who received miglustat 100 mg, orally, twice daily for 6 weeks. Decreased spermatogenesis with altered sperm morphology and motility and decreased fertility were observed in rats orally dosed with miglustat 14 days prior to mating with doses at exposures less than the human therapeutic systemic exposure based on body surface area comparisons (mg/m2). Decreased spermatogenesis was reversible in rats following 6 weeks of drug withdrawal [see Nonclinical Toxicology (13.1)].
Specific Populations
Gender: There was no statistically significant gender difference in miglustat pharmacokinetics, based on pooled data analysis.
Race: Ethnic differences in miglustat pharmacokinetics have not been evaluated in Gaucher patients. However, apparent oral clearance of miglustat in patients of Ashkenazi Jewish descent was not statistically different to that in others (1 Asian and 15 Caucasians), based on a cross-study analysis.
Hepatic Impairment: No studies have been performed to assess the pharmacokinetics of miglustat in patients with hepatic impairment.
Renal Impairment: Limited data in non-Gaucher patients with impaired renal function indicate that the apparent oral clearance (CL/F) of miglustat decreases with decreasing renal function. While the number of subjects with mild and moderate renal impairment was very small, the data suggest an approximate decrease in the apparent oral clearance of 40% and 60% respectively, in mild and moderate renal impairment, justifying the need to decrease the dosing of miglustat in such patients dependent upon creatinine clearance levels [see Dosage and Administration (2.2)].
Data in severe renal impairment are limited to two patients with creatinine clearances in the range 18-29 mL/min and cannot be extrapolated below this range. These data suggest a decrease in CL/F by at least 70% in patients with severe renal impairment [see Dosage and Administration (2.2) and Use in Specific Populations (8.6)].
Drug Interaction Studies
Miglustat does not inhibit the metabolism of various substrates of cytochrome P450 enzymes including, CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP4A11 in vitro; consequently significant interactions via inhibition of these enzymes are unlikely with drugs that are substrates of cytochrome P450 enzymes.
Drug interaction between Zavesca (miglustat 100 mg orally three times daily) and imiglucerase 7.5 or 15 U/kg/day was assessed in imiglucerase-stabilized patients after one month of co-administration. There was no significant effect of imiglucerase on the pharmacokinetics of miglustat, with the co-administration of imiglucerase and miglustat resulting in a 22% reduction in Cmax and a 14% reduction in the AUC for miglustat. While Zavesca appeared to increase the clearance of imiglucerase by 70%, these results are not conclusive because of the small number of subjects studied and because patients took variable doses of imiglucerase [see Drug Interactions (7)].
Concomitant therapy with loperamide during clinical trials did not appear to significantly alter the pharmacokinetics of miglustat.
Open-Label Uncontrolled Monotherapy Trials
In Study 1, Zavesca was administered at a starting dose of 100 mg three times daily for 12 months (dose range of 100 once-daily to 200 mg three times daily) to 28 adult patients with type 1 Gaucher disease, who were unable to receive enzyme replacement therapy and who had not taken enzyme replacement therapy in the preceding 6 months. Twenty-two patients completed the trial. After 12 months of treatment, the results showed significant mean percent reductions from baseline in liver volume of 12% and spleen volume of 19%, a non-significant increase from baseline in mean absolute hemoglobin concentration of 0.26 g/dL and a mean absolute increase from baseline in platelet counts of 8 × 109/L (See Tables 3-6).
In Study 2, Zavesca was administered at a dose of 50 mg three times daily for 6 months to 18 adult patients with type 1 Gaucher disease who were unable to receive enzyme replacement therapy and who had not taken enzyme replacement therapy in the preceding 6 months. Seventeen patients completed the trial. After 6 months of treatment, the results showed significant mean percent reductions from baseline in liver volume of 6% and spleen volume of 5%. There was a non-significant mean absolute decrease from baseline in hemoglobin concentration of 0.13 g/dL and a non-significant mean absolute increase from baseline in platelet counts of 5 × 109/L (See Tables 3-6).
Extension Period
Eighteen patients were enrolled in a 12-month extension to Study 1. A subset of patients continuing in the extension had larger mean baseline liver volumes, and lower mean baseline platelet counts and hemoglobin concentrations than the original study population (See Tables 3-6). After a total of 24 months of treatment, there were significant mean decreases from baseline in liver and spleen organ volumes of 15% and 27%, respectively, and significant mean absolute increases from baseline in hemoglobin concentration and platelet count of 0.9 g/dL and 14 × 109/L, respectively (See Tables 3-6).
Sixteen patients were enrolled in a 6-month extension to Study 2. After a total of 12 months of treatment, there was a mean decrease from baseline in spleen organ volume of 10%, whereas the mean percent decrease in liver organ volume remained at 6%. There were no significant changes in hemoglobin concentrations or platelet counts (See Tables 3-6).
Liver volume results from Studies 1 and 2 and their extensions are summarized in Table 3:
Table 3: Liver Volume Changes in Two Open-Label Uncontrolled Monotherapy Trials of Zavesca with Extension Period | | Liver Volume |
|---|
| n | Absolute Mean (L) (2-sided 95% CI) | Percent Mean (%) (2-sided 95% CI) |
|---|
| Study 1 (starting dose Zavesca 100 mg three times daily) | | | |
| Baseline (Month 0) | 21 | 2.39 | |
| Month 12 Change from baseline | | -0.28 (-0.38, -0.18) | -12.1% (-16.4, 7.9) |
| Study 1 Extension Phase | | | |
| Baseline (Month 0) | 12 | 2.54 | |
| Month 24 Change from baseline | | -0.36 (-0.48, -0.24) | -14.5% (-19.3, 9.7) |
| Study 2 (Zavesca 50 mg three times daily) | | | |
| Baseline (Month 0) | 17 | 2.45 | |
| Month 6 Change from baseline | | -0.14 (-0.25, -0.03) | -5.9% (-9.9, -1.9) |
| Study 2 Extension Phase | | | |
| Baseline (Month 0) | 13 | 2.35 | |
| Month 12 Change from baseline | | -0.17 (-0.3, -0.0) | -6.2% (-12.0, -0.5) |
Spleen volume results from Studies 1 and 2 and their extensions are summarized in Table 4:
Table 4: Spleen Volume Changes in Two Open-Label Uncontrolled Monotherapy Trials of Zavesca with Extension Period | | Spleen Volume |
|---|
| n | Absolute Mean (L) (2-sided 95% CI) | Percent Mean (%) (2-sided 95% CI) |
|---|
| Study 1 (starting dose Zavesca 100 mg three times daily) | | | |
| Baseline (Month 0) | 18 | 1.64 | |
| Month 12 Change from baseline | | -0.32 (-0.42, -0.22) | -19.0% (-23.7, -14.3) |
| Study 1 Extension Phase | | | |
| Baseline (Month 0) | 10 | 1.56 | |
| Month 24 Change from baseline | | -0.42 (-0.53, -0.30) | -26.4% (-30.4, -22.4) |
| Study 2 (Zavesca 50 mg three times daily) | | | |
| Baseline (Month 0) | 11 | 1.98 | |
| Month 6 Change from baseline | | -0.09 (-0.18, -0.01) | -4.5% (-8.2, -0.7) |
| Study 2 Extension Phase | | | |
| Baseline (Month 0) | 9 | 1.98 | |
| Month 12 Change from baseline | | -0.23 (-0.46, 0.00) | -10.1% (-20.1, -0.1) |
Hemoglobin concentration results from Studies 1 and 2 and their extensions are summarized in Table 5:
Table 5: Hemoglobin Concentration Changes in Two Open-Label Uncontrolled Monotherapy Trials of Zavesca with Extension Period | | Hemoglobin Concentration |
|---|
| n | Absolute Mean (g/dL) (2-sided 95% CI) | Percent Mean (%) (2-sided 95% CI) |
|---|
| Study 1 (starting dose Zavesca 100 mg three times daily) | | | |
| Baseline (Month 0) | 22 | 11.94 | |
| Month 12 Change from baseline | | 0.26 (-0.05, 0.57) | 2.6% (-0.5, 5.7) |
| Study 1 Extension Phase | | | |
| Baseline (Month 0) | 13 | 11.03 | |
| Month 24 Change from baseline | | 0.91 (0.30, 1.53) | 9.1% (2.9, 15.2) |
| Study 2 (Zavesca 50 mg three times daily) | | | |
| Baseline (Month 0) | 17 | 11.60 | |
| Month 6 Change from baseline | | -0.13 (-0.51, 0.24) | -1.3% (-4.4, 1.8) |
| Study 2 Extension Phase | | | |
| Baseline (Month 0) | 13 | 11.94 | |
| Month 12 Change from baseline | | 0.06 (-0.73, 0.85) | 1.2% (-5.2, 7.7) |
Platelet count results from Studies 1 and 2 and their extensions are summarized in Table 6:
Table 6: Platelet Count Changes in Two Open-Label Uncontrolled Monotherapy Trials of Zavesca with Extension Period | | Platelet Count |
|---|
| n | Absolute Mean (109/L) (2-sided 95% CI) | Percent Mean (%) (2-sided 95% CI) |
|---|
| Study 1 (starting dose Zavesca 100 mg three times daily) | | | |
| Baseline (Month 0) | 22 | 76.58 | |
| Month 12 Change from baseline | | 8.28 (1.88, 14.69) | 16.0% (-0.8, 32.8) |
| Study 1 Extension Phase | | | |
| Baseline (Month 0) | 13 | 72.35 | |
| Month 24 Change from baseline | | 13.58 (7.72, 19.43) | 26.1% (14.7, 37.5) |
| Study 2 (Zavesca 50 mg three times daily) | | | |
| Baseline (Month 0) | 17 | 116.47 | |
| Month 6 Change from baseline | | 5.35 (-6.31, 17.02) | 2.0% (-6.9, 10.8) |
| Study 2 Extension Phase | | | |
| Baseline (Month 0) | 13 | 122.15 | |
| Month 12 Change from baseline | | 14.0 (-3.4, 31.4) | 14.7% (-1.4, 30.7) |
Open-Label Active-Controlled Trial
Study 3 was an open-label, randomized, active-controlled study of 36 adult patients with type 1 Gaucher disease, who had been receiving enzyme replacement therapy with imiglucerase for a minimum of 2 years prior to study entry. Patients were randomized 1:1:1 to one of three treatment groups, as follows:
- Zavesca 100 mg three times daily alone
- imiglucerase (patient's usual dose) alone
- Zavesca 100 mg three times daily and imiglucerase (usual dose)
Patients were treated for 6 months, and 33 patients completed the study. Because Zavesca is only indicated as monotherapy, the results for the monotherapy arms are described below. At Month 6, the results showed a decrease in mean percent change in liver volume in the Zavesca treatment group compared to the imiglucerase alone group. There were no significant differences between the groups for mean absolute changes in liver and spleen volume and hemoglobin concentration. However, there was a significant difference between the Zavesca alone and imiglucerase alone groups in platelet counts at Month 6, with the Zavesca alone group having a mean absolute decrease in platelet count of 21.6 × 109/L and the imiglucerase alone group having a mean absolute increase in platelet count of 10.1 × 109/L (See Tables 7-10).
Extension period
Twenty-nine patients were enrolled in a 6-month extension to Study 3. In the extension phase, all 29 patients had withdrawn from imiglucerase and received open-label Zavesca 100 mg three times daily monotherapy. At Month 12, the results showed non-significant decreases in platelet counts from baseline in all the treatment groups (by original randomization). There was a significant decrease in platelet counts from Month 6 to Month 12 in the group originally randomized to treatment with imiglucerase, and a continued decrease in platelet counts in the group originally randomized to Zavesca alone. There were no significant changes in any treatment group for liver volume, spleen volume, or hemoglobin concentration (See Tables 7-10).
Liver volume results from Study 3 and extension are summarized in Table 7:
Table 7: Liver Volume Changes from Study 3 and Extension Phase | Imiglucerase alone | Zavesca alone |
|---|
| Study 3 | n=11 | n=10 |
| Month 0 | 1.81 | 1.58 |
| Month 6 Change (L) | 0.04 | -0.05 |
| Month 6 % Change | 3.6% | -2.9% |
| Adjusted mean Difference from Imiglucerase (95% CI) | | -4.5% (-13.2, 4.2) |
| Extension Phase All patients received Zavesca 100 mg three times daily monotherapy from Month 6 to Month 12. | n=10 | n=8 |
| Month 0 | 1.94 | 1.60 |
| Month 12 Change (L) | -0.05 | -0.01 |
| Month 12 % Change | -0.7% | -0.8% |
Spleen volume results from Study 3 and extension are summarized in Table 8:
Table 8: Spleen Volume Changes from Study 3 and Extension Phase | Imiglucerase alone | Zavesca alone |
|---|
| Study 3 | n=8 | n=7 |
| Month 0 | 0.61 | 0.69 |
| Month 6 Change (L) | -0.02 | -0.03 |
| Month 6 % Change | -2.1% | -4.8% |
| Adjusted % Difference from Imiglucerase (95% CI) | | -5.8% (-22.1, 10.5) |
| Extension Phase All patients received Zavesca 100 mg three times daily monotherapy from Month 6 to Month 12. | n=7 | n=6 |
| Month 0 | 0.83 | 0.57 |
| Month 12 Change (L) | 0.04 | -0.05 |
| Month 12 % Change | 1.5% | -6.1% |
Hemoglobin concentration results from Study 3 and extension are summarized in Table 9:
Table 9: Hemoglobin Concentration Changes from Study 3 and Extension Phase | Imiglucerase alone | Zavesca alone |
|---|
| Study 3 | n=12 | n=10 |
| Month 0 | 13.18 | 12.44 |
| Month 6 Change (g/dL) | -0.15 | -0.31 |
| Month 6 % Change | -1.2% | -2.4% |
| Adjusted % Difference from Imiglucerase (95% CI) | | -1.9% (-6.4, 2.6) |
| Extension Phase All patients received Zavesca 100 mg three times daily monotherapy from Month 6 to Month 12 . | n=10 | n=9 |
| Month 0 | 13.39 | 12.46 |
| Month 12 Change (g/dL) | -0.48 | -0.13 |
| Month 12 % Change | -3.1% | -1.1% |
Platelet count results from Study 3 and extension are summarized in Table 10:
Table 10: Platelet Count Changes from Study 3 and Extension Phase | Imiglucerase alone | Zavesca alone |
|---|
| Study 3 | n=12 | n=10 |
| Month 0 | 165.75 | 170.55 |
| Month 6 Change (109/L) | 15.29 | -21.60 |
| Month 6 % Change | 10.1% | -9.6% |
| Adjusted % Difference from Imiglucerase (95% CI) | | -17.1% (-32.9, -1.3) |
| Extension Phase All patients received Zavesca 100 mg three times daily monotherapy from Month 6 to Month 12. | n=10 | n=9 |
| Month 0 | 170.05 | 184.83 |
| Month 12 Change (109/L) | -3.75 | -27.39 |
| Month 12 % Change | -3.2% | -10.4% |
Patients with platelet counts above 150 × 109/L at baseline who were randomized to Zavesca treatment had significant decreases in platelet counts at Month 12.
Information for Patients
- Advise patients that the most common serious adverse reactions reported with Zavesca are peripheral neuropathy. Advise patients to promptly report any numbness, tingling, pain, or burning in the hands and feet [see Warnings and Precautions (5.1)].
- Advise patients that other adverse reactions include tremor and reductions in platelet counts. Advise patients to promptly report the development of tremor or worsening in an existing tremor. [see Warnings and Precautions (5.2 and 5.4)]
- Advise patients that other serious adverse reactions include diarrhea and weight loss. Advise patients to adhere to dietary instructions [see Warnings and Precautions (5.3)].
- Advise patients to take the next Zavesca capsule at the next scheduled time if a dose is missed.
- Inform patients of the potential risks and benefits of Zavesca and of alternative modes of therapy.
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©2017 Actelion Pharmaceuticals US, Inc.
Issued: November 2017
ACT20171108