Altimmune stock slumps ~35% amid phase 2 trial data of obesity drug pemvidutide

Altimmune (NASDAQ:ALT) stock fell ~35% premarket on Tuesday after the company reported data from a phase 2 trial and phase 1b study of its obesity therapy pemvidutide.

Phase 2 trial:

The study, dubbed MOMENTUM, expected to enroll 320 people with obesity or overweight with at least one co-morbidity and without diabetes. People were randomized 1:1:1:1 to 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo given weekly for 48 weeks along with diet and exercise.

The company reported today an interim analysis of 160 people who completed 24 weeks of treatment.

The company said that at Week 24, people receiving pemvidutide achieved average weight losses of 7.3%, 9.4% and 10.7% at the 1.2 mg, 1.8 mg, and 2.4 mg doses, respectively, with the placebo group seeing a mean weight loss of 1.0%.

In addition, people with baseline body weight less than or equal to 115 kg (75% of the study population) achieved average weight losses of 8.2% on 1.2 mg; 10.6% on 1.8 mg; and 11.9% on 2.4 mg.

The company noted that about 50% of people achieved 10% or more weight loss and approximately 20% of subjects achieved 15% or more weight loss at Week 24 at the 1.8 mg and 2.4 mg doses.

Altimmune noted that reductions in waist circumference and serum lipids were also seen. Meanwhile, clinically meaningful reductions in blood pressure were achieved without meaningful increases in heart rate.

Glucose homeostasis was maintained, with no significant changes in fasting glucose or HbA1c, according to the company.

In relation to safety, upper gastrointestinal (GI) events of nausea and vomiting were the majority of adverse events AEs. The events were mainly mild and moderate in severity, dose-related and similar in frequency to those seen in prior studies of pemvidutide, the company added.

One person experienced a serious adverse event of nausea and vomiting requiring rehydration, at the 2.4 mg dose.

Treatment discontinuation rates were 28.2% in people on placebo, majority of which were due to withdrawal of consent; while 24.0% in patients on pemvidutide, half of which were attributed to GI AEs, as per Altimmune.

"We believe that the 1.2 mg and 1.8 mg doses used without dose titration would be attractive options for primary care physicians and that we have the opportunity to improve further upon the profile of pemvidutide by utilizing higher doses in patients with more severe degrees of obesity, by allowing dose reduction and by employing a more prolonged titration for doses higher than 1.8 mg in our future trials," said Altimmune's President and CEO Vipin Garg.

Phase 1b trial:

This study was evaluating the safety profile of pemvidutide in people with overweight or obesity and type 2 diabetes. The trial consisted of 54 people who received either 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo administered weekly for 12 weeks.

The company said people on pemvidutide achieved average weight losses of 4.4% at 1.2 mg; 6.1% at 1.8 mg; and 7.7% at 2.4 mg, while the placebo group saw a mean weight gain of 0.8%, over the 12 weeks.

Glucose homeostasis was maintained over 12 weeks, with no significant changes in fasting glucose or HbA1c and no hyperglycemic (high blood sugar) AEs, the company added.

Altimmune noted that no SAEs were seen in patients on pemvidutide. Rates of GI AEs were low, and there were no AEs that lead to trial discontinuation.

ALT -37.27% to $6.85 premarket March 21