William Blair downgraded Assembly Biosciences (NASDAQ:ASMB) to “market perform” from “outperform” after the company discontinued clinical development of ABI-H2158, its second-generation core inhibitor for the treatment of chronic hepatitis B virus. The stock closed at $3.90 on Sept. 1.
Analyst Raju Prasad, Ph.D., writes that the decision was reached after four patients treated with ABI-2158 in the ongoing Phase 2 clinical study developed grade 3 or grade 4 elevations in alanine transaminase (ALT), consistent with drug-induced hepatotoxicity.
Moving forward, he said the company is continuing development of its third- and fourth-generation core inhibitors, ABI-H3733 and ABI-4334, and plans to present data from the Phase 1a healthy volunteer study of 3733 at an upcoming medical meeting. Management expects 4334 to advance to the clinic in 2022.
In addition, Assembly has two Phase 2 triple combination studies in the clinic. “Based on our discussions with key opinion leaders, we believe these triple combination approaches could lead to enhanced viral suppression, compared with any single agent or double combination,” Dr. Prasad said. “After speaking with management, we believe that we could see the interim results of these trials in 2022.”