FDA Grants Fast Track Designation to Hepatitis B Drug

Hepatitis B virus core inhibitor under evaluation in a pair of global phase 2a proof of concept studies.

The FDA recently granted Fast Track designation to Assembly Biosciences, Inc’s novel treatment for patients with chronic hepatitis B virus (HBV) infection. The drug, ABI-H0731, is the manufacturer’s lead oral HBV core inhibitor, according to a press release.

It is currently being evaluated in a pair of global phase 2a proof of concept studies.

“More than 1 million individuals in the US suffer from chronic hepatitis B infection, which can progress to cirrhosis and liver cancer, eventually leading to death. Despite existing antiviral therapies, cures are rare, so the need for more effective and potentially curative treatments is tremendous,” said Uri Lopatin, MD, chief medical officer of Assembly Biosciences. “We are encouraged that ABI-H0731 was granted Fast Track designation. This will allow us to work closely with the FDA in our efforts to bring this new therapy to HBV patients as quickly as possible.”

Assembly’s ongoing HBV drug development program seeks to advance a new class of potent, oral core inhibitors that could boost cure rates for chronically-infected patients with HBV, according to the press release. The concurrent trials for the experimental HBV drug are currently recruiting and dosing subjects at multiple locations worldwide.

ABI-H0731-201 is a “viral antigen trial” enrolling HBeAg-positive HBV patients who have a previously-suppressed viral load on a standard-of-care nucleos(t)ide therapy.

Patients enrolled in the trial are randomized to receive either daily ABI-H0731 or placebo along with their continued nucleos(t)ide therapy for 6 months, according to the release. The researchers are seeking to evaluate the treatment’s efficacy in reducing HBV S antigens and HBV E antigens, as well as the safety and tolerability of the combination treatment compared with the standard-of-care nucleos(t)ide monotherapy.

The ABI-H0731-202 “viral load trial” is enrolling HBeAg positive HBV patients who are naïve to nucleos(t)ide treatment. These patients will be randomized to receive either daily ABI-H0731 or placebo plus entecavir for 6 months.

The researchers seek to determine antiviral potency as measured by viral DNA suppression, as well as the safety and tolerability of the combination versus entecavir monotherapy. Assembly Biosciences expects initial results from the 2 studies in the first half of 2019, according to the press release.

"Even with indefinite treatment with the currently available nucleoside and nucleotide inhibitors, we are not able to fully suppress viral replication, which will be necessary for patients to achieve a cure for chronic HBV," said Douglas T. Dieterich, MD, director, Institute of Liver Medicine, professor of Medicine at Mount Sinai, New York, who is an investigator on both trials. "Core inhibitors target different parts of the HBV life cycle than the current therapies and may result in both greater viral suppression and increased loss of cccDNA, which is central to HBV persistence. Combining these new mechanisms of action with existing direct acting antivirals looks promising. I look forward to exploring this further in the trials and seeing the results."