Gaining approval by the EC and Japanese Ministry of Health, Labour and Welfare (MHLW) on the same day for adults with moderate-to-severe active rheumatoid arthritis (RA) is a clear win for the developers of Jyseleca (filgotinib), however, this was at the heels of an FDA complete response letter (CRL). Given the importance of this market, the loss of revenue from the delayed US approval is certain to hurt, says GlobalData, a leading data and analytics company.

GlobalData estimated the size of the 2019 market for rheumatoid arthritis in the eight major markets* at $25.2bn, with the US accounting for 73.9% of sales, at $18.7bn.

Heather Leach, PhD, Director of Immunology at GlobalData, comments: “With the time needed to re-file and wait for an FDA review, GlobalData expects that US approval for Jyseleca will come in Q1 2022 – a year and a half after the initial expectation. This delay, and the ultimate shift in its uptake curve, is expected to result in nearly $800m lost revenue for RA.”

The CRL issued to Gilead and Galapagos for Jyseleca requested results from two ongoing Phase II trials, titled MANTA and MANTA-Ray, which were initiated in men to evaluate the impact of the drug on sperm parameters – following a concern that stemmed from preclinical animal models that showed a reduction in sperm counts. Primary endpoints for the MANTA trials are reading out in January 2021.

Leach continues: “Presuming data from the MANTA and MANTA-RAy trials pan out, and that Jyseleca wins US approval for RA in a timely manner, GlobalData does not expect the initial struggles to impact approvals in other autoimmune indications. However, overall sales may not reach the high values originally anticipated.

“Industry forecasts for filgotinib in 2018 placed the drug at achieving as high as $4-6bn at peak, but this estimate relied in-part on the assumption of superior safety. Still, with sales of its three competitors at $2.8bn for 2019 – and rising – there is clearly room for more than one blockbuster in the JAK race.”

*8MM: The US, France, Germany, Italy, Spain, the UK, Japan and Australia