Menarini Group Shares NEXPOVIO (selinexor) Subgroup Data from BOSTON trial at the European Hematology Association Congress, Highlighting Clinical Potential in Relapsed/Refractory Multiple Myeloma

• Data demonstrate a significant 71% reduction in risk of disease progression or death in selinexor + bortezomib + dexamethasone (SVd) arm versus bortezomib + dexamethasone (Vd) arm in PI-naïve patients
• Data demonstrate a significant 47% reduction in risk of death with SVd versus Vd in multiple myeloma patients who are refractory to treatment with lenalidomide

FLORENCE, Italy, June 8, 2023 /PRNewswire/ -- The Menarini Group ("Menarini"), a leading Italian pharmaceutical and diagnostics company, and Stemline Therapeutics, Inc. ("Stemline"), a wholly-owned subsidiary of the Menarini Group, today announced important new data on NEXPOVIO (selinexor) at the European Hematology Association (EHA) Congress 2023.

The two abstracts at EHA bring new subgroup data from the Phase 3 BOSTON study (NCT03110562) in relapsed refractory multiple myeloma (RRMM). In patients with just one prior line of treatment, median progression-free survival (mPFS) was 21 months for those treated with SVd, versus 10.7 months for those treated with Vd alone (HR 0.62). In proteasome inhibitor (PI)-naïve patients, the mPFS was 29.5 months with SVd compared to 9.7 months with Vd alone (HR 0.29). In patients who were refractory to lenalidomide, overall survival was 26.7 months for the SVd arm, compared to 18.6 months for the Vd arm (HR 0.53). These efficacy analyses were based on the final data cut from the BOSTON trial in February 2021, representing a one-year update of previously presented data from 2020.

"The data presented today emphasize the synergy between selinexor and bortezomib, highlighting the importance of a double mode of action switch. These results are particularly relevant considering the increased use of the daratumumab lenalidomide dexamethasone combination in clinical practice today," said Professor Maria-Victoria Mateos, MD, PhD, University Hospital Salamanca, Spain. "These findings further support the use of selinexor in combination with bortezomib in PI / bortezomib-naïve or lenalidomide-refractory RRMM patients, as well as for patients at first relapse."

"We are proud to present these new subgroup data on selinexor," said Elcin Barker Ergun, CEO of the Menarini Group. "We are committed to bringing transformative new therapeutic options to the patients and families affected by cancer, including multiple myeloma."

The most common (≥25%) treatment-emergent adverse events (AEs) with SVd versus Vd in patients with one prior line of treatment were thrombocytopenia (61.6% vs 28.6%), nausea (52.5% vs 11.2%), fatigue (45.4% vs 17.3%), peripheral neuropathy (38.4% vs 52.0%), diarrhea (34.3% vs 24.5%), and anemia (30.3% vs 26.5%). Safety findings were similar in the PI-naïve and bortezomib-naïve subgroups, as well as the lenalidomide refractory subgroup. Safety data in these subgroups were consistent with those observed in the overall BOSTON study population.