Summit Therapeutics (SMMT) Status Update summary

Financial and strategic updates

• Accepted an unsolicited offer from an institutional investor to purchase $200 million of common stock at $9 per share, a premium to the previous closing price, with board approval.

• Expanded license territories for ivonescimab to include Latin America, Middle East, and Africa, in addition to existing regions, through an amended agreement with Akeso.

• The expanded territory deal is valued at up to $70 million.

Clinical development and trial progress

• Four Phase III clinical trials for ivonescimab are ongoing, including multi-regional and single-region studies targeting advanced non-small cell lung cancer.

• HARMONi-A Phase III trial met its primary endpoint, showing significant improvement in progression-free survival (PFS) for ivonescimab plus chemotherapy versus placebo plus chemotherapy in EGFR-mutant NSCLC patients post-TKI therapy, with a hazard ratio of 0.46 and median PFS of 7.1 vs. 4.8 months (p<0.001).

• PFS benefit was consistent regardless of brain metastasis status, with HRs of 0.40 (no brain metastasis) and 0.48 (with brain metastasis); early overall survival analysis showed early separation of curves and median OS of 17.1 vs. 14.5 months (HR 0.80).

• Ivonescimab monotherapy in the HARMONi-2 trial demonstrated statistically significant superiority in PFS over pembrolizumab in first-line PD-L1 positive NSCLC.

• HARMONi trial will incorporate 85% of HARMONi-A patients as the Asia region, with additional enrollment from North America and Europe to reach 420 patients, targeting completion in the second half of 2024.

Safety and adverse events

• Any grade treatment-related adverse events (TRAEs) occurred in 98.1% of ivonescimab plus chemo patients and 95.0% of placebo plus chemo patients.

• Grade ≥3 TRAEs were reported in 54.0% (ivonescimab) versus 42.9% (placebo); serious TRAEs in 28.6% versus 16.1%.

• Most common adverse events (≥15%) included decreased WBC count, anemia, neutrophil count decrease, and elevated liver enzymes.

• Immune-related adverse events of any grade occurred in 24.2% of ivonescimab plus chemo patients, with hypothyroidism and hyperthyroidism being most frequent.

• Adverse events of special interest included proteinuria (29.8% any grade), haemorrhage (8.1%), and hypertension (8.1%) in the ivonescimab arm.