Regeneron Pharmaceuticals (REGN) Investor Update summary

Program overview and rationale

• Factor XI program targets unmet needs in anticoagulation, aiming to reduce bleeding risk and expand treatment to underutilized populations, supported by genetic and epidemiological data.

• Two mechanistically distinct antibodies (catalytic/REGN7508 Cat and A2/REGN9933A2) are designed for tailored therapy: one for maximal efficacy, the other for minimal bleeding risk.

• The program prioritizes indications with strong genetic and clinical validation, such as VTE, cardioembolic stroke, and atrial fibrillation.

Preclinical and clinical data

• Both antibodies demonstrated robust inhibition of Factor XI activity and superior potency compared to competitors in preclinical assays.

• Phase 2 ROCCI/ROXI-VTE studies in knee replacement showed REGN7508 Cat had the lowest VTE rates (7.1%), outperforming apixaban (12.4%) and enoxaparin (20.6%), with no major or clinically relevant non-major bleeds in any arm.

• REGN9933A2 also outperformed enoxaparin (VTE rate 17.2%), with no major or clinically relevant non-major bleeding.

• Interim data in catheter-associated thrombosis showed 66% and 47% relative risk reduction in clot detection for catalytic and A2 antibodies, respectively.

• GI bleed studies indicated no increased bleeding risk when Factor XI antibodies were combined with aspirin, unlike DOACs.

Safety and adverse events

• No major or clinically relevant non-major bleeding occurred in any treatment arm; only one minimal bleeding event (contusion) was reported in the enoxaparin group.

• Adverse event rates were similar across all treatment arms, with postoperative anemia being the most common, and no treatment-related serious adverse events or trial discontinuations.