Ablynx is about to wrap up its Phase 2 trials of vobarilizumab (ALX-0061) for patients with rheumatoid arthritis, and is discussing a move toward Phase 3 studies with U.S. and European regulatory authorities.
The processes are, however, shrouded in disappointment as Ablynx partner AbbVie decided not to exercise its right to license vobarilizumab to continue the Phase 3 development.
Vobarilizumab is an antibody fragment that targets the IL-6 receptor. Ablynx has adopted the term Nanobody for such single-domain antibodies. IL-6 is an immune cytokine that plays various roles in rheumatoid arthritis. It activates T-cells, triggers the production of other inflammatory factors, and activates cells that break down bone.
Two Phase 2b trials, which included a total of 596 patients, have shown vobarilizumab to be both safe and effective in managing symptoms.
One trial (NCT02287922) explored the drug as a single treatment and demonstrated that vobarilizumab brought about 60 percent more patients into remission at week 12 compared to Actemra (tocilizumab) — the only currently approved IL-6 targeting antibody.
In the second trial (NCT02309359), vobarilizumab was given in combination with methotrexate. Data from this trial was compared to studies of leading commercial biologicals and oral rheumatoid arthritis drugs in development, showing that the drug was very effective when measuring ACR70 (at least 70 percent improvement in a number of disease parameters) and remission.
Studies have also demonstrated that the Nanobody has an advantage to other drugs. A common problem in rheumatoid treatment is the development of antibodies targeting a drug. Such immune reactions tend to make the treatment less efficient, but such antibodies do not seem to prevent vobarilizumab from doing its work.
As the Phase 2b trials commenced, AbbVie stated that it would exercise its right to opt-in and licence vobarilizumab if the studies met certain pre-defined success criteria.
“We are obviously disappointed that AbbVie has decided at this time not to exercise its right to license vobarilizumab in rheumatoid arthritis,” Dr. Edwin Moses, CEO of Ablynx, said in a press release.
“The strong Phase 2b results in RA demonstrated that vobarilizumab is not just another antibody but a member of a new therapeutic class with unique differentiating features resulting in a superior efficacy and safety profile as compared to other biologicals,” Moses said.
Ablynx is now seeking a new partner to continue the clinical development. Meanwhile, plans for Phase 3 are ongoing, and Ablynx expects the first patients to be enrolled by the end of 2017.
“I have great confidence in our clinical team’s proven ability to prepare and implement our Phase 3 plan while we identify a committed partner for the future development and commercialization of the product,” Moses said.
Vobarilizumab is also being explored in a long-term extension study (NCT02518620) which includes rheumatoid arthritis patients who participated in the Phase 2b trials.