Ablynx’s RA drug matches Roche’s Actemra in PhIIb, but doubts about AbbVie buy-in remain

(By Alvesgaspar - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19263411)

EuroBiotech logoAblynx (EBR:ABLX) has posted Phase IIb data showing its anti-IL-6R antibody vobarilizumab can compete with Roche’s ($RHHBY) rheumatoid arthritis drug Actemra. But, with vobarilizumab failing to blow Actemra out of the water in terms of efficacy, doubts remain about whether AbbVie ($ABBV) will take up its option on the Ablynx drug.

Ghent, Belgium-based Ablynx compared three blinded dose groups of vobarilizumab, also known as ALX-0061, to an open-label cohort of Actemra in a 12-week study. The trial enrolled 251 patients with moderate to severe forms of rheumatoid arthritis who were intolerant to methotrexate. Ablynx assessed the efficacy of the various regimens using ACR20--a measure of the proportion of patients whose condition improves by 20%--and the harder-to-achieve ACR50 and ACR70. DAS28, an endpoint FDA sees as being more sensitive to change than the ACR scores, was also used.

Across the three vobarilizumab arms, between 73% and 81% of participants hit ACR20, an accepted measure of reduction of disease activity. In the Actemra arm, 78% of participants met ACR20. Data on ACR50 and ACR70 were similarly closely matched. For ACR50, the vobarilizumab range was 37% to 49%, compared to 45% in the Actemra arm. And for ACR70, 16% to 24% for vobarilizumab played off against 23% for Actemra. While the ACR data suggest vobarilizumab works, they fall short of showing how it can take market share from Roche’s rival IL-6 drug.

The ability, or otherwise, of Ablynx to demonstrate vobarilizumab has an edge over Actemra will shape its near-term future. AbbVie has an option to pick up the drug after it gets a look at data from a second Phase IIb trial that is giving vobarilizumab in combination with methotrexate. A decision is pencilled in for the fourth quarter.

If AbbVie takes up the option, it will give Ablynx $75 million (€68 million), agree to fund the Phase III program and commit to up to $425 million in milestones plus double-digit royalties. AbbVie picked up the option in 2013 when it wrote Ablynx a check for $175 million and committed to $665 million in milestones.

How much of that potential windfall Ablynx will ultimately see will depend on AbbVie’s reading of the data. While the ACR results fall short of making a clear-cut case for vobarilizumab, Ablynx thinks other aspects of its data set show why a physician may prescribe its drug over Actemra. Most patients in the Actemra arm received the drug every week. Vobarilizumab achieved similar levels of efficacy when given every two weeks. Ablynx’s drug may also have the edge in terms of safety. Fewer patients in the vobarilizumab arms dropped out of the trial or experienced treatment-related adverse events.

When paired to DAS28 data that may favor the use of vobarilizumab over Actemra, Ablynx thinks these factors amount to a compelling case. The $75 million question is, does AbbVie agree? History suggests it may be unwise to second-guess what path AbbVie will take.

Last summer, the question of whether AbbVie would take up its $200 million option on Galapagos’ ($GLPG) rheumatoid arthritis drug filgotinib was seen as almost a foregone conclusion. Speculation in some quarters had moved on to whether AbbVie would just opt-in or buy Galapagos outright. Then, in September, AbbVie jilted Galapagos and prioritized development of its rival to filgotinib.

Ablynx shares climbed 15% following the release of the data.

- read the release (PDF)

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