Prothena downgraded to Perform from Outperform at Oppenheimer

Oppenheimer downgraded Prothena (PRTA) to Perform from Outperform without a price target based on the Phase 3 AFFIRM-AL trial for birtamimab in amyloid light chain amyloidosis that failed to meet the primary endpoint of all-cause mortality. With a hazard ratio of 0.915, the survival curve for birtamimab essentially overlapped with the control arm, the analyst tells investors in a research note. Oppenheimer remains optimistic about Prothena’s several internal and partnered programs, but says the the AFFIRM-AL catalyst was a main driver behind its bullish thesis.