AnaptysBio (ANAB) Study Update summary

Study design and patient population

• Phase II-B/2b RENOIR trial enrolled 424 moderate-to-severe RA patients randomized to three rosnilimab doses or placebo, all on stable cDMARD background, across the US, Canada, and Europe.

• Patient demographics were balanced, with mean age 57, 76% female, mean disease duration 10 years, and 59–60% bio-naïve and 40–41% bio-experienced in each group.

• Primary endpoint was mean change in DAS28-CRP at week 12; key secondary endpoints included ACR20/50/70 and CDAI LDA at weeks 12 and 14.

• Only patients achieving CDAI LDA (≤10) at week 14 continued blinded active treatment through week 28.

• Baseline characteristics were typical for RA studies, with most patients classified as severe.

Efficacy results

• Statistically significant improvement in DAS28-CRP at week 12 for all rosnilimab doses versus placebo (p-values: 0.0062, 0.0016, 0.0092).

• At week 12, up to 75% achieved ACR20 and 69% achieved CDAI LDA, with highest ever reported responses for these endpoints at week 14.

• ACR50 and ACR70 responses deepened from week 12 to 14, with sustained or increasing efficacy through week 28 in CDAI LDA responders.

• Efficacy was robust across bio-naïve and bio-experienced subgroups, with up to 75% CDAI LDA and 88% ACR20 at week 14.

• Week 14 efficacy surpassed all-active head-to-head comparator studies at week 24, especially in bio-experienced patients.

Safety and tolerability

• Rosnilimab was safe and well tolerated, with adverse event rates similar to placebo and no increase in serious infections, malignancies, MACE, or anaphylaxis.

• Most common AEs were headache and upper respiratory tract infection; low rates of severe or drug-related SAEs and injection site reactions.

• No treatment-related severe AEs, SAEs, or systemic hypersensitivity observed; discontinuation rates were very low and unrelated to study drug.

• Safety profile remained consistent through week 28 for patients continuing therapy.