Summit Therapeutics Inc. (SMMT): First global ivo Phase 3 frontline lung cancer data takes center stage in 2H

Research evidence excerpt

Summit Therapeutics Inc. (SMMT): First global ivo Phase 3 frontline lung cancer data takes center stage in 2H

Goldman Sachs Summit Therapeutics Inc. (SMMT)

weekend (link), where notably, ivo + chemotherapy demonstrated a statistically

significant OS benefit — 27.9 months vs. 23.7 months for Tevimbra (ONC’s anti-PD-1,

similar to MRK’s Keytruda) + chemotherapy — with a hazard ratio (HR) of 0.66 (95% CI,

0.50 to 0.87; one-sided P =0.0017). Post the strong HARMONi-6 PFS data (HR=0.60;

p<0.0001) previously shared at the 2025 European Society for Medical Oncology (ESMO)

conference, HARMONi-6 is also the first Ph3 study to demonstrate OS benefit against

PD1+chemo in frontline NSCLC, the global standard-of-care. During the trial discussion

portion of the ASCO presentation, the discussant KOL highlighted a perceived lower OS

benefit seen in older patients (age≥65) - however, SMMT management notes the lower

benefit seen in older patients (age≥65) was due to baseline imbalances on target lesion

size and brain metastases in that subgroup - per the HARMONi-6 progression-free

survival (PFS) data at ESMO 2025, once adjusting for covariates, PFS HR in this subgroup

was in-line, and management expects this would apply to OS as well. Additionally, the

OS curves separate at 6 months and continue to widen over time, providing greater

confidence in the result, and ivo median OS would not have been reached without the

last event, suggesting favorable maturation is likely.

We are constructive into the final PFS and interim OS readout from the global Ph3

HARMONi-3 study squamous NSCLC cohort in 2H, noting ivo’s profile remains strong in

our view per the HARMONi-6 data, which confirmed PFS to OS benefit translation,

de-risking HARMONi-3. Acknowledging the HARMONi-3 interim PFS readout missed