An FDA advisory committee backed approval of Eli Lilly and Incyte’s baricitinib for rheumatoid arthritis yesterday, but their verdict raises doubts about the competitiveness of the drug.
The panel gave its blessing to the lower 2mg dose of the JAK inhibitor for adult patients with moderately-to-severely active RA who don’t respond to or cannot tolerate methotrexate, but concluded that the higher 4mg dose – while effective – may not be sufficiently safe based on the submitted data.
Committee members were almost unanimous on the efficacy of the two doses, but were much less aligned on safety, with the 2mg safety vote split nine to six amid discussion about baricitinib’s potential to cause side effects such as pulmonary embolism and venous thromboembolism.
Lilly has put a brave face on the outcome, saying that it is “confident that baricitinib, if approved, can help people in the US manage the challenges of living with RA”. But analysts think the drug faces an uphill battle now to win market share from Pfizer’s Xeljanz (tofacitinib), the first JAK inhibitor to reach the market for RA in the US and a blockbuster product with sales of $1.35bn in 2017.
Both doses of Lilly and Incyte’s drug are already approved in the EU, where it is sold as Olumiant, and the product brought in total revenues for Lilly of $46m in 2017, with half of that total coming in the last three months of the year.
In the US, Lilly and Incyte has suggested that the 2mg dose should be used first with 4mg reserved for non-responders. However, analysts at Credit Suisse said in a research note ahead of the advisory committee meeting that “experts we have spoken to believe approval of the 4mg dose is critical for them to use the product in any meaningful way”.
“An approval of the 2mg dose only … will likely be negatively received by both the medical community and investors,” they continued.
Of course, the FDA doesn’t have to follow its advisors’ advice, but the outcome of the meeting chimes fairly well with the briefing document published by the agency’s reviewers in preparation for the committee meeting.
Taking on Xeljanz isn’t the only challenge for baricitinib, however, as it could soon see additional competition from other JAK inhibitors including Gilead Sciences’ filgotinib and AbbVie’s upadacitinib. Analyst Josh Schimmer of Evercore ISI reckons the latter is a particular threat, especially as the trials carried out with the drug showed a clear dose response between the 15mg and 30mg doses used.
There has been debate about whether all the JAK inhibitors might be affected by blood clot concerns, but the FDA briefing document seems to suggest the issue is specific to baricitinib, saying “thrombosis was a unique finding with baricitinib, and not seen with other JAK kinase inhibitors, such as tofacitinib”.
It’s a disappointment for Lilly, but arguably will be felt more keenly by Incyte as baricitinib has grown in importance for the company following the failed trial of its IDO1-targeting cancer immunotherapy epacadostat alongside Merck & Co/MSD’s Keytruda (pembrolizumab) in melanoma.