Lerodalcibep and evolocumab for the treatment of homozygous familial hypercholesterolaemia with PCSK9 inhibition (LIBerate-HoFH): a phase 3, randomised, open-label, crossover, non-inferiority trial.

BACKGROUND

Lerodalcibep, a small binding anti-PCSK9 protein (adnectin), showed effective LDL cholesterol reduction in heterozygous familial hypercholesterolaemia. We aimed to assess the safety and efficacy of lerodalcibep and evolocumab in a globally diverse homozygous familial hypercholesterolaemia population.

METHODS

This phase 3, randomised, open-label, crossover, non-inferiority study consisted of two 24-week treatment periods separated by an 8-week washout. The study was conducted in 12 lipid clinics in six countries (India, Israel, Norway, South Africa, Türkiye, and the USA). Patients aged 10 years or older with genetically confirmed homozygous familial hypercholesterolaemia were randomly assigned by computer-generated randomisation scheme performed centrally via interactive response technology to either monthly lerodalcibep 300 mg (1·2 mL subcutaneous injection) or monthly evolocumab 420 mg (subcutaneous 9 min infusion of 3·5 mL) for 24 weeks (period A) followed by an 8-week washout and then crossed over to the alternate therapy for the next 24 weeks (period B). The trial was open label, but all efficacy parameters were masked to patients, study staff, and the sponsor from randomisation. The primary efficacy endpoint was the percent change from baseline (day 1 of period A) in LDL cholesterol concentration to week 24 for period A and B. The intention-to-treat (ITT) population, defined as all randomly assigned patients, was used for the primary analysis. The safety population included all patients who received any study medication. The margin used to establish non-inferiority was 6%. The trial is registered with ClinicalTrials.gov (NCT04034485) and EudraCT (2019-003611-62), and has now finished.

FINDINGS

Patients were enrolled from Nov 11, 2019, to July 2, 2021, and the final study visit took place on Aug 8, 2022. Of 82 patients screened, 66 entered period A (ITT population). The mean age was 28·7 years (SD 15·2); 20 (30%) of 66 were paediatric patients; 36 (55%) of 66 were female and 30 (45%) of 66 were male; and the mean baseline LDL cholesterol was 10·59 mmol/L (SD 4·37). Mean LDL cholesterol reduction by ITT analysis at week 24 was -4·9% (SE 3·5) on lerodalcibep compared with -10·3% (3·5) on evolocumab; the mean difference between treatments was 5·4% (95% CI -0·2 to 11·1), which did not show non-inferiority at the prespecified 6% margin. LDL cholesterol response varied considerably across the patient population but was generally similar in the same patients with both lerodalcibep and evolocumab. When averaged across all monthly visits, LDL cholesterol response was -9·1% (SE 3·2) on lerodalcibep and -10·8% (3·2) on evolocumab. Importantly, genotyping and free PCSK9 suppression were not predictive of response. Both drugs were well tolerated, with no treatment-related serious adverse events. Injection site reactions were reported in one (2%) of 65 patients on lerodalcibep and 15 (24%) of 62 patients on evolocumab.

INTERPRETATION

The LDL cholesterol response was highly variable, but generally similar in patients treated with both lerodalcibep and evolocumab. Importantly, the study showed the inability to predict response based on genotyping, reinforcing the rationale for PCSK9 inhibition in all patients with homozygous familial hypercholesterolemia and continuing its use in responders.

FUNDING

LIB Therapeutics.