BlossomHill Reports 45% Response Rate in Trial of Treatment for C797S-Mutated Lung Cancer
Key Facts
BlossomHill Therapeutics on September 15 announced results from the SOLARA trial showing an objective response rate of 45% among patients with non-small cell lung cancer associated with EGFR C797S resistance, and a disease control rate of 88%. The company said responses were recorded in 18 of 40 patients and disease control in 35 of 40. The trial is evaluating BH-30643 in patients carrying the mutation, while the company is working with Foundation Medicine to develop a companion diagnostic test to verify its detection in the study. The test is intended to identify patients suitable for the experimental treatment. The company announced plans to start a global Phase 2 study for this patient group in the first quarter of 2027.
The results reflect a group that had previously received multiple treatments: the median number of prior lines of therapy was two, 98% of patients had received osimertinib, and 35% also carried the T790M mutation. The company said data announced in September showed that 25 of 40 patients remained on treatment in an efficacy follow-up through August 10, 2026. Median follow-up was 6.9 months, while the presentation data cutoff was May 12, 2026. These figures place the response and disease-control results within ongoing patient follow-up, rather than as final trial results. The study remains at the clinical stage, while the company plans to move to a Phase 2 trial.
On safety, the company said treatment-related dose reductions were reported in 9% of the 174 patients treated at the specified expansion doses, while treatment-related discontinuations were 3%. Those doses included 40 mg, 50 mg and 60 mg twice daily. The figures cover patients treated at the expansion doses cited in the September update and do not, on their own, provide final results on the drug's safety in broader use. Alongside BH-30643, the company presented preliminary clinical data during 2026 for BH-30236 in relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndromes. It also presented preclinical data for the BH-501284 program targeting KRAS.
The company secured additional funding for its program through an August public offering that sold 10,516,240 shares, including the partial exercise of the overallotment option, raising $168.3 million in gross proceeds. The offering price was set at $16.00 per share, with trading on Nasdaq expected to begin on August 7 and closing expected on August 10, 2026. After its second-quarter results, the company reported cash and cash equivalents of $95.4 million as of June 30. It said it expects to fund operations through the second quarter of 2028 following the offering. This gives the company a stated funding runway as it prepares for the next stages of the drug's development.
The roadmap includes a planned meeting with the U.S. Food and Drug Administration in the fourth quarter of 2026 to discuss the end of Phase 1, the recommended Phase 2 dose and a potential accelerated-approval pathway. The company aims to dose the first patient in a Phase 2 trial during the first quarter of 2027. It also said it plans to start a global study targeting patients with C797S-positive non-small cell lung cancer in the first quarter of that year. These milestones remain announced plans subject to execution and clinical progress. The SOLARA data published to date represent part of the path leading up to the planned start of the study.