EQRx announced a late-breaking mini oral presentation of data from its partner CStone Pharmaceuticals' phase 3 GEMSTONE-301 study at the European Society for Medical Oncology (ESMO) Congress 2021. GEMSTONE-301 is a placebo-controlled phase 3 trial evaluating the efficacy and safety of the anti-PD-L1 antibody sugemalimab as consolidation therapy in patients with locally advanced/unresectable Stage III non-small cell lung cancer (NSCLC) without disease progression after concurrent or sequential chemoradiotherapy. GEMSTONE-301 is the first positive phase 3 trial of a PD-(L)1 agent in this broad stage III NSCLC patient population setting.

In May 2021, EQRx, along with its partner CStone Pharmaceuticals, announced that the GEMSTONE-301 study met its primary endpoint of prolonged progression-free survival (PFS). Detailed results of the study to be presented at ESMO 2021 on September 18, 2021, are as follows: Sugemalimab, as a consolidation therapy, demonstrated statistically significant and clinically meaningful improvement in PFS vs. placebo as assessed by blinded independent central review (BICR).

Median PFS was 9.0 months vs. 5.8 months (HR=0.64, P=0.0026). Clinical benefits were observed in patients who received either concurrent or sequential chemoradiotherapy prior to sugemalimab.

For patients who received prior concurrent chemoradiotherapy (cCRT), median PFS was 10.5 months vs. 6.4 months (HR=0.66). For patients who received prior sequential chemoradiotherapy (sCRT), median PFS was 8.1 months vs.

4.1 months (HR=0.59). Overall survival (OS) data were immature, but an encouraging trend for a survival benefit with sugemalimab vs. placebo was observed with follow-up of patients ongoing.

Median OS was not reached for sugemalimab vs. 24.1 months for placebo (HR=0.44). Sugemalimab had a well-tolerated safety profile and no new safety signals were observed.

The upcoming presentation at ESMO 2021 in stage III NSCLC builds upon the recent presentation of updated data from the GEMSTONE-302 study in stage IV NSCLC at the IASLC 2021 World Conference on Lung Cancer, positioning sugemalimab as a potential treatment option to address both stage III and IV NSCLC. Separately, a poster is also being presented at ESMO 2021 on the final results of the phase 2 APOLLO study, conducted by EQRx's partner Hansoh Pharma, of EGFR inhibitor aumolertinib in second-line NSCLC. Data demonstrate an encouraging OS benefit with a median OS of 30.2 months in patients with EGFR T790M-positive advanced NSCLC after disease progression on first-/second-generation EGFR TKI therapies.