On March 4, Galapagos announced pooled interim results from its ongoing MANTA and MANTA-RAy testicular safety studies for Jyseleca (filgotinib) in men with inflammatory bowel disease (IBD) or rheumatic diseases, respectively. The data demonstrate that treatment with Jyseleca for 13 weeks had no negative effect on sperm concentration when compared to placebo. Pending outcomes from MANTA and MANTA-RAy were key factors in the FDA’s decision to reject Gilead’s New Drug Application (NDA) for Jyseleca in the treatment of rheumatoid arthritis (RA), which contributed to the company withdrawing its filing in late 2020. Despite giving up on RA, Gilead and Galapagos have maintained an interest in pursuing FDA approval of Jyseleca for ulcerative colitis (UC) and Crohn’s disease (CD). Positive data from MANTA and MANTA-RAy bolster hope for Jyseleca in the US IBD space.
Interim data from MANTA and MANTA-RAy should ease fears regarding Jyseleca’s potential impact on sperm health. Although the trials were not powered for comparison across groups, numerically fewer patients treated with Jyseleca (200mg) versus placebo experienced a 50% or greater decline in sperm concentration over the initial 13-week double-blind treatment period (6.7% vs. 8.3%). The study protocols require that patients exhibiting a 50% or greater decline in sperm concentration enter a monitoring phase in which they are evaluated every 13 weeks for reversibility, up to 52 weeks. Secondary endpoints from MANTA and MANTA-RAy, including additional semen parameters at 13-week and 26-week time points, will be reported after all patients in the monitoring phase have completed the observation period.
If the FDA is satisfied with the interim results from MANTA and MANTA-RAy, Gilead and Galapagos could file an NDA for Jyseleca in UC as early as this year, with pending approval in 2022. Assuming positive Phase III data in the ongoing DIVERSITY1 trial, approval in CD would likely follow soon after. However, GlobalData believes the approval of Jyseleca in UC and CD will likely be pushed out to 2023 due to the need for testicular safety data at later time points. In a press release published in late 2020, Gilead made it clear that for the FDA to complete their review of Jyseleca, the agency would require follow-up data on sperm concentration recovery up to Week 52.
Although sperm health was a key concern in Jyseleca’s rocky regulatory proceedings for RA, these data will arguably be of even greater importance to the FDA when considering the drug’s applications in UC and CD, as these diseases are more likely to affect younger men. According to GlobalData’s epidemiological analysis, in 2021, men between the ages of 20 and 65 will comprise around 35% of the total diagnosed prevalent cases of CD and UC (among patients 20 years of age or older). In contrast, this group of patients accounts for only 13% of cases in RA.
GlobalData believes that UC and CD could prove to be very promising markets for Jyseleca in the US. Although IBD is a smaller market than RA, with expected 2021 sales of $13.2B versus $20.9B in the US, according to GlobalData, Jyseleca has similar or perhaps even greater sales potential in UC and CD due to more limited competition. In the US, there are currently five and six targeted immunomodulating drugs approved for the treatment of CD and UC, respectively—half the number available for RA. If approved, GlobalData forecasts sales for Jyseleca will reach $95.1M and $129M in UC and CD, respectively, by 2029.