BlossomHill reports 45% response rate for BH-30643 in EGFR C797S lung cancer

BlossomHill Therapeutics announced updated data on September 15, 2026 from its ongoing Phase 1/2 SOLARA trial of BH-30643, an investigational EGFR inhibitor, in patients with non-small cell lung cancer carrying secondary EGFR resistance mutations. The findings were presented in a mini-oral session at the IASLC 2026 World Conference on Lung Cancer in Seoul, South Korea.¹

Among patients with EGFR C797S-positive resistance following prior EGFR inhibitor treatment, regardless of concurrent T790M status, BH-30643 produced a 45% objective response rate (18 of 40 patients) and an 88% disease control rate (35 of 40).¹ At the efficacy follow-up, 63% of patients (25 of 40) remained on treatment, with a median follow-up of 6.9 months.¹

The trial population was heavily pretreated: patients had received a median of two prior lines of therapy, 98% had prior osimertinib, 53% had prior chemotherapy and/or an antibody-drug conjugate, and 53% had a history of brain metastases.¹ Thirty-five percent of patients had concurrent T790M.¹

On safety, among 174 patients treated at doses of 40 mg, 50 mg and 60 mg twice daily, treatment-related dose reductions and discontinuations occurred in 9% and 3% of patients, respectively.¹ The most common treatment-related adverse event was bilirubin elevation, generally asymptomatic and predominantly unconjugated, consistent with UGT1A1 inhibition by BH-30643.¹

The presentation followed BH-30643 receiving FDA Fast Track designation for advanced or metastatic EGFR C797S-positive NSCLC.¹ The company said it plans to move into Phase 2 study. BlossomHill plans to initiate a global Phase 2 study targeting EGFR C797S-positive NSCLC in the first quarter of 2027.¹ SOLARA is a global Phase 1/2, first-in-human trial spanning more than 40 sites in 10 countries, registered as NCT06706076.¹