The safety and effectiveness of JUXTAPID as an adjunct to a low-fat diet and other lipid-lowering treatments, including LDL apheresis where available, were evaluated in a multinational, single-arm, open-label, 78-week trial involving 29 adults with HoFH. A diagnosis of HoFH was defined by the presence of at least one of the following clinical criteria: (1) documented functional mutation(s) in both LDL receptor alleles or alleles known to affect LDL receptor functionality, or (2) skin fibroblast LDL receptor activity <20% normal, or (3) untreated TC >500 mg/dL and TG <300 mg/dL and both parents with documented untreated TC >250 mg/dL.
Among the 29 patients enrolled, the mean age was 30.7 years (range, 18 to 55 years), 16 (55%) were men, and the majority (86%) were Caucasian. The mean body mass index (BMI) was 25.8 kg/m2, with four patients meeting BMI criteria for obesity; one patient had type 2 diabetes. Concomitant lipid-lowering treatments at baseline included one or more of the following: statins (93%), ezetimibe (76%), nicotinic acid (10%), bile acid sequestrant (3%), and fibrate (3%); 18 (62%) were receiving apheresis.
After a six-week run-in period to stabilize lipid-lowering treatments, including the establishment of an LDL apheresis schedule if applicable, JUXTAPID was initiated at 5 mg daily and titrated to daily doses of 10 mg, 20 mg, 40 mg, and 60 mg at weeks 2, 6, 10, and 14, respectively, based on tolerability and acceptable levels of transaminases. Patients were instructed to maintain a low-fat diet (<20% calories from fat) and to take dietary supplements that provided approximately 400 international units vitamin E, 210 mg alpha-linolenic acid (ALA), 200 mg linoleic acid, 110 mg eicosapentaenoic acid (EPA), and 80 mg docosahexaenoic acid (DHA) per day. After efficacy was assessed at Week 26, patients remained on JUXTAPID for an additional 52 weeks to assess long-term safety. During this safety phase, the dose of JUXTAPID was not increased above each patient's maximum tolerated dose established during the efficacy phase, but changes to concomitant lipid-lowering treatments were allowed.
Twenty-three (79%) patients completed the efficacy endpoint at Week 26, all of whom went on to complete 78 weeks of treatment. Adverse events contributed to premature discontinuation for five patients [see Adverse Reactions (6.1)]. The maximum tolerated doses during the efficacy period were 5 mg (10%), 10 mg (7%), 20 mg (21%), 40 mg (24%), and 60 mg (34%).
The primary efficacy endpoint was percent change in LDL-C from baseline to Week 26. At Week 26, the mean and median percent changes in LDL-C from baseline were -40% (paired t-test p<0.001) and -50%, respectively, based on the intent-to-treat population with last observation carried forward (LOCF) for patients who discontinued prematurely. The mean percent change in LDL-C from baseline through Week 26 is shown in Figure 1 for the 23 patients who completed the efficacy period.
| Figure 1: Mean Percent Change in LDL-C from Baseline (Week 26 Completers) |
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| Error bars represent 95% confidence intervals of the mean. |
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Changes in lipids and lipoproteins through the efficacy endpoint at Week 26 are presented in Table 8.
Table 8: Absolute Values and Percent Changes from Baseline in Lipids and Lipoproteins | PARAMETER | BASELINE | WEEK 26/LOCF (N=29) |
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| Mean (SD) | Mean (SD) | Mean % Change |
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| LDL-C, direct (mg/dL) | 336 (114) | 190 (104) | -40 |
| TC (mg/dL) | 430 (135) | 258 (118) | -36 |
| apo B (mg/dL) | 259 (80) | 148 (74) | -39 |
| Non-HDL-C (mg/dL) | 386 (132) | 217 (113) | -40 |
| VLDL-C (mg/dL) | 21 (10) | 13 (9) | -29 |
| TG (mg/dL) | 92 [72, 128] | 57 [36, 78] | -45 |
| HDL-C (mg/dL) | 44 (11) | 41 (13) | -7 |
After Week 26, during the safety phase of the study, adjustments to concomitant lipid-lowering treatments were allowed. For the study population overall, average reductions in LDL-C, TC, apo B, and non-HDL-C were sustained during chronic therapy.