Piper Sandler analyst Danielle Brill raised her price target for Acceleron Pharma to $135 from $73 after the Phase 2 proof-of-concept study of sotatercept in pulmonary arterial hypertension met its primary endpoint and key secondary efficacy endpoints. The stock in premarket trading is up 66%, or $35.13, to $88.00. Importantly, the results also met Acceleron's predefined threshold for clinical significance, Brill tells investors in a research note. While few details were provided in the release, the positive findings in this "robust" Phase 2 provides "solid evidence" for sotatercept's role as a disease-modifying agent for pulmonary arterial hypertension, contends the analyst. She reiterates an Overweight rating on Acceleron shares.