Altimmune bails on hepatitis B after phase 2 data disappoint, quashing partnering plans

Altimmune has been beaten by hepatitis B. The drug candidate, which the company was preparing for partnering, failed to meet the bar for further development in a phase 2 study, prompting the biotech to stop development and focus on its GLP-1/glucagon dual receptor agonist. 

Maryland-based Altimmune designed its hepatitis B prospect, HepTcell, to activate T cells to fight against the virus. A phase 1 trial found the immunotherapeutic increased the T-cell response against hepatitis B antigens. The early data emboldened Altimmune to run an 80-subject, placebo-controlled study to show whether HepTcell could drive reduction or clearance of the hepatitis B surface antigen.

Now, Altimmune has revealed that the overall response “was deemed to be insufficient to warrant further advancement.” The biotech responded by halting development of HepTcell. Altimmune’s stock fell 19% to $7 in premarket trading Wednesday.

Positive phase 2 data could have led to a deal for Altimmune. The biotech saw its candidate as a good partner for direct-acting antivirals in drug combinations intended to achieve a functional cure. Lacking a direct-acting antiviral, Altimmune planned to talk to companies with potentially complementary assets such as siRNA, antibody and oligonucleotide molecules about trialing combination therapies. 

The lackluster phase 2 data seemingly close off that opportunity and leave Altimmune focused on its GLP-1/glucagon dual receptor agonist pemvidutide. Altimmune shared phase 2 data on the drug candidate late last year, unveiling results that suggest pemvidutide may match approved rivals on weight loss and drive deeper drops in LDL cholesterol than the incumbents. 

Altimmune used its fourth-quarter results to provide another data point. Three-quarters of the weight lost by people on pemvidutide came from fat tissue rather than lean mass. The figure in studies of Novo Nordisk’s semaglutide is around 60%, leading Altimmune CEO Vipin Garg, Ph.D., to cite preservation of lean mass as another way pemvidutide could distinguish itself from established weight loss drugs. 

The biotech is also developing pemvidutide as a treatment for metabolic dysfunction-associated steatohepatitis and expects to have top-line 24-week data from a phase 2b trial in the first quarter of next year.