Lomitapide

Risk Summary

Based on findings from animal studies, lomitapide use is contraindicated in pregnancy since it may cause fetal harm. Available human data are insufficient to draw conclusions about any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, in animal reproduction studies, lomitapide was teratogenic in rats at clinically relevant exposures and in ferrets at exposures estimated to be less than human therapeutic exposure at 60 mg when administered during organogenesis, based on AUC comparisons. Embryo-fetal lethality was observed in rabbits at 6-times the maximum recommended human dose (MRHD) of 60 mg based on body surface area. If pregnancy is detected, discontinue lomitapide.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

Oral gavage doses of 0.04, 0.4, or 4 mg/kg/day lomitapide given to pregnant rats from gestation day 6 through organogenesis were associated with fetal malformations at ≥2-times human exposure at the MRHD (60 mg) based on plasma AUC comparisons. Fetal malformations included umbilical hernia, gastroschisis, imperforate anus, alterations in heart shape and size, limb malrotations, skeletal malformations of the tail, and delayed ossification of cranial, vertebral and pelvic bones.

Oral gavage doses of 1.6, 4, 10, or 25 mg/kg/day lomitapide given to pregnant ferrets from gestation day 12 through organogenesis were associated with both maternal toxicity and fetal malformations at exposures that ranged from less than the human exposure at the MRHD to 5-times the human exposure at the MRHD. Fetal malformations included umbilical hernia, medially rotated or short limbs, absent or fused digits on paws, cleft palate, open eye lids, low-set ears, and kinked tail.

Oral gavage doses of 0.1, 1, or 10 mg/kg/day lomitapide given to pregnant rabbits from gestation day 6 through organogenesis were not associated with adverse effects at systemic exposures up to 3-times the MRHD of 60 mg based on body surface area comparison. Treatment at doses of ≥20 mg/kg/day, ≥6-times the MRHD, resulted in embryo-fetal lethality.

Pregnant female rats given oral gavage doses of 0.1, 0.3, or 1 mg/kg/day lomitapide from gestation day 7 through termination of nursing on lactation day 20 were associated with malformations at systemic exposures equivalent to human exposure at the MRHD of 60 mg based on AUC. Increased pup mortality occurred at 4-times the MRHD.

Risk Summary

There are no data on the presence of lomitapide in human or animal milk, effects on the breastfed infant or on milk production. Because of the potential for serious adverse reactions, including hepatotoxicity, advise patients that breastfeeding is not recommended during treatment with lomitapide.

In a 2-year dietary carcinogenicity study in mice, lomitapide was administered at doses of 0.3, 1.5, 7.5, 15, or 45 mg/kg/day. There were statistically significant increases in the incidences of liver adenomas and carcinomas in males at doses ≥1.5 mg/kg/day (≥2-times the MRHD at 60 mg based on AUC) and in females at ≥7.5 mg/kg/day (≥10-times the human exposure at 60 mg based on AUC). Incidences of small intestinal carcinomas in males and combined adenomas and carcinomas in females were significantly increased at doses ≥15 mg/kg/day (≥23-times the human exposure at 60 mg based on AUC).

In a 2-year carcinogenicity study in rats, lomitapide was administered by oral gavage for up to 99 weeks at doses of 0.25, 1.7, or 7.5 mg/kg/day in males and 0.03, 0.35, or 2.0 mg/kg/day in females. While the design of the study was suboptimal, there were no statistically significant drug-related increases in tumor incidences at exposures up to 6-times (males) and 8-times (females) higher than human exposure at the MRHD based on AUC.

Lomitapide did not exhibit genotoxic potential in a battery of studies, including the in vitro Bacterial Reverse Mutation (Ames) assay, an in vitro cytogenetics assay using primary human lymphocytes, and an oral micronucleus study in rats.

Lomitapide had no effect on fertility in rats at doses up to 5 mg/kg/day at systemic exposures estimated to be 4-times (females) and 5-times (males) higher than in humans at 60 mg based on AUC.

• Risk of hepatotoxicity
• Reduced absorption of fat-soluble vitamins, and serum fatty acids
• Gastrointestinal adverse reactions

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

One single-arm, open-label, 78-week trial has been conducted in 29 patients with HoFH, 23 of whom completed at least one year of treatment. The initial dosage of lomitapide was 5 mg daily, with titration up to 60 mg daily during an 18-week period based on safety and tolerability. In this trial, the mean age was 30.7 years (range, 18 to 55 years), 16 (55%) patients were men, 25 (86%) patients were Caucasian, 2 (7%) were Asian, 1 (3%) was African American, and 1 (3%) was multi-racial.

Five (17%) of the 29 patients with HoFH that participated in the clinical trial discontinued treatment due to an adverse reaction. The adverse reactions that contributed to treatment discontinuations included diarrhea (2 patients; 7%) and abdominal pain, nausea, gastroenteritis, weight loss, headache, and difficulty controlling INR on warfarin (1 patient each; 3%).

The most common adverse reactions were gastrointestinal, reported by 27 (93%) of 29 patients. Adverse reactions reported by ≥8 (28%) patients in the HoFH clinical trial included diarrhea, nausea, vomiting, dyspepsia, and abdominal pain. Other common adverse reactions, reported by 5 to 7 (17-24%) patients, included weight loss, abdominal discomfort, abdominal distension, constipation, flatulence, increased ALT, chest pain, influenza, nasopharyngitis, and fatigue.

The adverse reactions reported in at least 10% of patients during the HoFH clinical trial are presented in Table 1.

Table 1. Adverse Reactions Reported in ≥10% of Patients in the Clinical Trial in HoFH:

Adverse reactions of severe intensity were reported by 8 (28%) of 29 patients, with the most common being diarrhea (4 patients, 14%), vomiting (3 patients, 10%), increased ALT or hepatotoxicity (3 patients, 10%), and abdominal pain, distension, and/or discomfort (2 patients, 7%).

Transaminase Elevations

During the HoFH clinical trial, 10 (34%) of 29 patients had at least one elevation in ALT and/or AST ≥3× ULN (see Table 2). No clinically meaningful elevations in total bilirubin or alkaline phosphatase were observed. Transaminases typically fell within one to four weeks of reducing the dose or withholding lomitapide.

Table 2. Patient Incidence of Transaminase Elevations During the HoFH Clinical Trial:

Upper limits of normal (ULN) ranged from 33-41 international units/L for ALT and 36-43 international units/L for AST.

Among the 19 patients who enrolled in an extension study following the HoFH clinical trial, one discontinued because of increased transaminases that persisted despite several dose reductions, and one temporarily discontinued because of markedly elevated transaminases (ALT 24× ULN, AST 13× ULN) that had several possible causes, including a drug-drug interaction between lomitapide and the strong CYP3A4 inhibitor clarithromycin.

Hepatic Steatosis

Hepatic fat was prospectively measured using magnetic resonance spectroscopy (MRS) in all eligible patients during the HoFH clinical trial. After 26 weeks, the median absolute increase in hepatic fat from baseline was 6%, and the mean absolute increase was 8% (range, 0% to 30%). After 78 weeks, the median absolute increase in hepatic fat from baseline was 6%, and the mean absolute increase was 7% (range, 0% to 18%). Among the 23 patients with evaluable data, on at least one occasion during the trial, 18 (78%) exhibited an increase in hepatic fat >5% and 3 (13%) exhibited an increase >20%. Data from individuals who had repeat measurements after stopping lomitapide show that hepatic fat accumulation is reversible, but whether histological sequelae remain is unknown.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of lomitapide. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to lomitapide exposure.

Musculoskeletal disorders: Myalgia

Skin reactions: Alopecia