Key takeaways:

• Lilly discontinued their PD-1 RA program in Oct’24, which triggered a dip in ANAB stock due to the parallel mechanism readthrough and skepticism going into this readout
• ANAB released data yesterday for their own PD-1 RA agonist (rosnilimab) that was overall positive, with a caveat: Week 12 data was okay, but Week 14 data was great, which raised concerns about potential bias being introduced (patients had to achieve a CDAI LDA score of ≤10 to be eligible to continue treatment); however, there is evidence this is a feature of PD-1 agonism, so investor response was mixed
• Given the widespread usage of Humira (adalimumab) and Remicade (infliximab), the most relevant patient population commercially (and the one flagged in the table above) is in patients with inadequate response or intolerance to DMARDs – while the timepoints don’t line up perfectly, on an absolute basis rosnilimab 14-week data held up well against Rinvoq 24-week data
• We’d expect rosnilimab data to continue to improve to 28-weeks (we’ll get an update later this year) and handily surpass Rinvoq. Real-world patients don’t discontinue treatment at either 12 or 14 weeks, so assessing efficacy durability at 28-weeks and beyond will be critical
• We uncovered 4 other disclosed programs targeting PD-1 in RA (J&J, Gilead, GeneSci and Santa Ana), although it's possible the Gilead and J&J programs have both been discontinued / deprioritized. We'd expect activity to pick up here on the basis of this data