A Study to Examine the Effects of the Leptin Receptor (LEPR) Agonist Antibody REGN4461 in Adult Patients With Familial Partial Lipodystrophy (FPLD)

Percent Change From Baseline to Week 12 in Fasting Serum TG (Cohorts B and A + B)

Percent change in fasting serum TG was reported for participants with elevated baseline fasting TG (\>200 mg/dL) in Cohort B and Cohorts A + B.

Time frame: Baseline to week 12

Change From Baseline to Week 12 in HbA1c (Cohorts B and A + B)

Change in HbA1c was reported for participants with elevated baseline HbA1c (\>7.0%) in Cohort B and Cohorts A + B.

Time frame: Baseline to week 12

Percent Change From Baseline to Weeks 12 and 24 in Fasting Serum TG (Study Arm 1)

Percent change in fasting serum TG was reported for participants in Study Arm 1.

Time frame: Baseline, Week 12, Week 24

Percent Change From Baseline to Weeks 12 and 24 in Fasting Serum TG (Study Arm 2)

Percent change in fasting serum TG was reported for participants in Study Arm 2.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 in HbA1c (Study Arm 1)

Change from baseline in HbA1c was reported for participants in Study Arm 1.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 in HbA1c (Study Arm 2)

Change from baseline in HbA1c was reported for participants in Study Arm 2.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 in Fasting Glucose (Study Arm 1)

Change from baseline in fasting glucose was reported for participants in Study Arm 1.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 in Fasting Glucose (Study Arm 2)

Change from baseline in fasting glucose was reported for participants in Study Arm 2.

Time frame: Baseline, Week 12, Week 24

Percent Change From Baseline to Weeks 12 and 24 in Liver Fat Magnetic Resonance Imaging-derived Proton Density Fat Fraction (MRI-PDFF) (Study Arm 1)

Percent change from baseline in MRI-PDFF was reported for participants with baseline MRI-PDFF ≥8.5% in Study Arm 1.

Time frame: Baseline, Week 12, Week 24

Percent Change From Baseline to Weeks 12 and 24 in Liver Fat MRI-PDFF (Study Arm 2)

Percent change from baseline in MRI-PDFF was reported for participants with baseline liver fat MRI-PDFF ≥8.5% in Study Arm 2.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 on the Daily Lipodystrophy Hunger Questionnaire - Highest Hunger Score

The daily lipodystrophy hunger questionnaire was developed to assess hunger related behaviors among patients with lipodystrophy. The highest hunger score asked participants to rate their highest hunger that day on a scale from 0 to 4, with higher scores representing the higher perceived hunger. A negative change from baseline indicated a reduction in perceived hunger.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 on the Daily Lipodystrophy Hunger Questionnaire - Lowest Hunger Score

The daily lipodystrophy hunger questionnaire was developed to assess hunger related behaviors among patients with lipodystrophy. The lowest hunger score asked participants to rate their lowest hunger that day on a scale from 0 to 4, with higher scores indicating higher perceived hunger. A negative change from baseline score indicated a reduction in perceived lowest hunger.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 on the Daily Lipodystrophy Hunger Questionnaire - Felt Hungry Score

The daily lipodystrophy hunger questionnaire was developed to assess hunger related behaviors among participants with lipodystrophy. The felt hungry score asked how much time participants felt hunger that day on a scale from 0 to 4, with higher scores indicating more time feeling hungry. A negative change from baseline score indicated a reduction in time spent feeling hungry.

Time frame: Baseline, Week 12, Week 24

Change From Baseline to Weeks 12 and 24 on the Daily Lipodystrophy Hunger Questionnaire - Fullness Score

The daily lipodystrophy hunger questionnaire was developed to assess hunger related behaviors among patients with lipodystrophy. The fullness score asked participants to rate how often they felt full after eating that day on a scale from 0 to 4, with higher scores indicating higher feeling of fullness. A negative change from baseline indicated a reduced feeling of fullness.

Time frame: Baseline, Week 12, Week 24

Number of Participants With Treatment-emergent Adverse Events (TEAEs)

Time frame: Up to Day 169

Concentrations of REGN4461 in Serum

Time frame: Weeks 0, 1, 2, 3, 4, 5, 6, 9, 12, 13, 14, 15, 16, 17, 18, 21, 28, 32 and 36. Weeks 0 and 12 collected pre- and post-dose. All other time points were only pre-dose.

Number of Participants With Treatment-emergent Anti-drug Antibody (ADA) Response

Time frame: Up to Day 281