ABIVAX (Paris:ABVX) (Euronext Paris: FR0012333284 – ABVX), an innovative company developing anti-viral therapies and immunotherapeutics for infectious diseases like HIV/AIDS, chronic hepatitis B (CHB), chikungunya, ebola as well as an adjuvant to enhance the immune response, today announced that a futility analysis on the primary end-point of its ABX203-002 trial, a Phase IIb/III trial of ABX203 in CHB patients, determined that the trial is unlikely to reach its primary endpoint.
The ABX203-002 study is an open-label, randomized, comparative study designed to assess the efficacy of ABX203 to maintain control of the hepatitis B virus after cessation of nucleotide analogs (NUCs), in particular in controlling viral load for a much longer period of time when compared to current treatment options. This study is ongoing in seven Asian/Pacific countries (Taiwan, Hong-Kong, Thailand, Singapore, South Korea, Australia and New-Zealand). In this large scale controlled and randomized study, where 276 subjects were enrolled as of September 2015, one group of patients received ABX203 for 24 weeks, in addition to the current standard of care (nucleoside analogues, NUCs). All therapy was stopped after 24 weeks, and these patients are evaluated against a control group receiving NUCs only. The study’s primary efficacy endpoint is the percentage of subjects with viral load <40 IU/mL at week 48, i.e 24 weeks after the treatment with ABX203 has been completed.
An unscheduled futility analysis was initiated because of a recent increase in the patients’ drop out rate related to viral escape. A futility analysis is conducted during an ongoing clinical trial to describe the probability of a study to reach its primary endpoint. The result of this analysis shows that a positive outcome of the study regarding its primary endpoint is unlikely.
The Data Safety and Monitoring Board (DSMB) of study ABX203-002 was convened. The DSMB has recognized the good safety profile of ABX203 and recommended that the study should continue as per protocol, to monitor patients 24 weeks post-treatment in order to continue to assess their viral load and to have a comprehensive view of the secondary endpoints. Investigators, health authorities and patients are being informed of the conclusions of the DSMB.
In a previous Phase II study, with a different design and carried out in Asia, treatment-naïve patients with chronic hepatitis B were administered ABX203 as monotherapy. That study established a significantly longer period to viral rebound as compared to patients receiving Peg-Interferon Alpha.
The future development of ABX203 is under review, including the usefulness of an adjuvant boosting the response to this immunotherapy, as well as new administration schedules and therapeutic combinations that may be evaluated via other preclinical and, potentially, clinical testing.