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MorphoSys’ Phase 3 Study of Pelabresib in Myelofibrosis Demonstrates Statistically Significant Improvement in Spleen Volume Reduction and Strong Positive Trend in Symptom Reduction


Planegg/Munich, Germany, November 20, 2023 - MorphoSys AG (FSE: MOR; NASDAQ: MOR) today announced strong topline results from the Phase 3 MANIFEST-2 study investigating pelabresib, an investigational BET inhibitor, in combination with the JAK inhibitor ruxolitinib compared with placebo plus ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis.

MANIFEST-2 met its primary endpoint, as the combination therapy demonstrated a statistically significant and clinically meaningful improvement in the proportion of patients achieving at least a 35% reduction in spleen volume (SVR35) at week 24. 

The key secondary endpoints assessing symptom improvement – proportion of patients achieving at least a 50% reduction in total symptom score (TSS50) and absolute change in total symptom score (TSS) from baseline at week 24 – showed a strong positive trend favoring the pelabresib and ruxolitinib combination. In an analysis of patients classified as intermediate risk (Dynamic International Prognostic Scoring System [DIPSS] Int-1 and Int-2) – constituting more than 90% of patients in MANIFEST-2 – the combination therapy demonstrated significant improvements in both key secondary endpoints. DIPSS was a pre-defined stratification factor in the MANIFEST-2 study protocol.

Detailed findings of the Phase 3 MANIFEST-2 study will be presented during an oral presentation, held on Sunday, December 10, at 5:15 p.m. PST, at the 65th American Society for Hematology (ASH) Annual Meeting and Exposition in San Diego, California.

Press Release