Summit Therapeutics’ Closely-Watched Lung Cancer Study Of Ivonescimab Misses Overall Survival Endpoint – Summit Therapeutics (NASDAQ:SMMT)

Summit Therapeutics Inc. SMMT released topline results on Friday from the Phase 3 HARMONi trial of ivonescimab plus platinum-doublet chemotherapy compared to placebo plus platinum-doublet chemotherapy for epidermal growth factor receptor (EGFR)-mutated, locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have progressed after treatment with a 3rd generation EGFR tyrosine kinase inhibitor (TKI).

The trial met the progression-free survival (PFS) primary endpoint and showed a positive trend in the other primary endpoint, overall survival (OS).

At the prespecified primary data analysis, ivonescimab, in combination with chemotherapy, demonstrated a statistically significant and clinically meaningful improvement in progression-free survival, with a hazard ratio of 0.52.

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Ivonescimab, in combination with chemotherapy, showed a positive trend in OS in the primary analysis but did not achieve a statistically significant benefit, with a hazard ratio of 0.79 (p=0.057).

No new safety signals were noted in this Phase 3 study. Grade 3 or higher treatment-emergent adverse events (TEAEs) were reported for 56.9% of patients in the ivonescimab + chemotherapy arm vs. 50.0% with chemotherapy alone.

Fatal TEAEs (excluding disease progression) were reported for 1.8% of patients in the ivonescimab + chemotherapy arm vs. 2.8% in those patients receiving chemotherapy alone.

The safety profile of ivonescimab + chemotherapy was acceptable and manageable in the context of the observed clinical benefit.

Based on the HARMONi clinical trial results, Summit intends to file a Biologics License Application (BLA) to seek approval for ivonescimab plus chemotherapy in this setting.

Based on discussions with the FDA, Summit will consider the timing of the filing of this BLA.

The FDA noted that a statistically significant overall survival benefit is necessary to support marketing authorization, which will weigh into Summit’s considerations regarding the timing of a potential BLA filing.

In April, Summit Therapeutics noted that Akeso, Inc. announced the Chinese Health Authorities, the National Medical Products Administration (NMPA) approved ivonescimab for a second indication based on the results of the Phase 3 trial, HARMONi-2 or AK112-303.

Akeso announced the results of this interim overall survival analysis included a clinically meaningful hazard ratio of 0.777.

Summit Therapeutics’ partner, Akeso, Inc., released topline data from the Phase 3 HARMONi-6/K112-306 trial.

The trial met its primary endpoint of progression-free survival (PFS).

At a prespecified interim analysis conducted by an Independent Data Monitoring Committee, ivonescimab plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in PFS compared to BeiGene, Ltd’s ONCE Tevimbra (tislelizumab) plus chemotherapy.

The PFS benefit was demonstrated in patients with either PD-L1-positive or PD-L1-negative tumors.

Price Action: At the last check on Friday, SMMT stock was down 12.3% to $23 during the premarket session.

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