Ablynx Drug Fails Again in Mid-Stage Trial

For the second time Ablynx’s anti-IL-6R Nanobody, vobarilizumab has failed to pass muster. This morning Belgium-based company said vobarilizumab did not meet primary endpoints in a Phase II dosing study for lupus patients.

The primary endpoint of the mid-stage study was the percentage of subjects who achieved a dose-response at Week 24. Ablynx said there was no dose-response reported in patients after the 24 week period, according to a modified BILAG-based combined lupus assessment (mBICLA). The 312 patient trial tested four dose regimens of vobarilizumab plus one placebo dose in patients with moderate to severe, active seropositive systemic lupus erythematosus (SLE).

Systemic lupus erythematosus, the most common form of lupus, is an autoimmune disorder that triggers inflammation in different tissues of the body. SLE causes the immune system attacks its own tissues and causes widespread inflammation and tissue damage in the affected areas, according to the U.S. Centers for Disease Control and Prevention. Approximately five million people suffer from a form of SLE. About 90 percent of diagnosed patients are women.

In its announcement the company did not present full data regarding the failure, but it noted that demographics and baseline characteristics were similar across all treatment arms and were reflective of a typical SLE population. Ablynx did note that there were adverse events reported in 12.4 percent of all patients treated with vobarilizumab, including two deaths. That was in comparison to 6.5 percent treatment-emergent adverse events in the placebo group.

Vobarilizumab targets the interleukin 6 pathway via its IL-6 receptor (IL-6R). IL-6 is a pro-inflammatory cytokine that plays a role in T-cell activation, production of acute phase proteins in response to inflammation, induction of immunoglobulin production, and stimulation of osteoclast differentiation and activation.

 "We are disappointed that vobarilizumab didn't show a dose-response in the analysis of the study's primary endpoint, however, vobarilizumab was well tolerated in all tested dose groups, confirming its favorable safety profile. We will continue to analyze the full data set and thank the study participants and their families as well as the investigators and staff who contributed to this study," Robert K. Zeldin, chief medical officer at Ablynx, said in a statement.

In 2016 vobarilizumab failed to meet endpoints in a Phase IIb trial for rheumatoid arthritis. That failure prompted AbbVie to terminate a 2013 agreement that gave it developmental and commercial options for the drug in RA. However, under the initial agreement, AbbVie also has rights to vobarilizumab as an SLE treatment. In its announcement today Ablynx said AbbVie will review the Phase II lupus data to determine whether or not to exercise its option to license vobarilizumab.

"Should AbbVie exercise the option, it would trigger a payment to Ablynx. If the option is not exercised, Ablynx's agreement with AbbVie would terminate," the company said.

The news of the vobarilizumab failure in lupus comes two months after Ablynx agreed to be acquired by Sanofi in a deal worth $4.8 billion. Sanofi’s key interest was Ablynx’s lead compound caplacizumab (anti-vWF Nanobody), which is being developed as a treatment for acquired thrombotic thrombocytopenic purpura (aTTP).

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