Blossomhill Therapeutics, Inc. · NASDAQ:BLSM
Blossomhill Therapeutics — ASCO 2026
11 slides from Blossomhill Therapeutics's conference presentation, Sep 9, 2026
Slide 1: First-in-human trial of BH-30643, a novel macrocyclic OMNI-EGFR inhibitor, in EGFR-mutant NSCLC
First-in-human trial of BH-30643, a novel macrocyclic, non-covalent, mutant selective OMNI-EGFR inhibitor, in EGFR-mutant (EGFRm) NSCLC Xiuning Le1, Alexander I. Spira2, Divya Myadam Gupta3, Misako Nagasaka4, Jonathan W. Riess5, James Chih Hsin Yang6, Julia K. Rotow7, Lyudmila Bazhenova8, Molly SC L
Slide 2: Disclosures
Disclosures Xiuning Le, M.D., Ph.D. I have the following financial relationships to disclose: • Consulting / advisory fees: AbbVie, Abion, Akeso, Allist, ArriVent, AstraZeneca, Avistone, Bayer, BioNTech, BlossomHill, Boehringer Ingelheim, Bristol Myers Squibb, Daiichi Sankyo, Dizal, Eli Lilly, EMD S
Slide 3: BH-30643 is a macrocyclic OMNI-EGFR inhibitor
BH-30643 is a macrocyclic OMNI-EGFR inhibitor • BH-30643 is a small molecule designed to target the common active state of mutant EGFR, allowing high potency across a wide range of EGFR mutations while sparing wildtype EGFR1 • BH-30643 is 10-fold more potent than osimertinib against classical mutati
Slide 4: SOLARA Phase 1 study design and patient characteristics
SOLARA Phase 1 study design and patient characteristics Phase 1 escalation / backfill enrolled a heavily pretreated and heterogeneous patient population, with a median of 3 prior lines of therapy, 66% with history of brain metastases, and 71% ECOG=1 Phase 1 Part 1A (Escalation & backfill) Patients B
Slide 5: Pharmacokinetics: Phase 1 escalation / backfill experience
Pharmacokinetics: Phase 1 escalation / backfill experience • Median steady state plasma exposures at ≥40mg BID achieved high coverage over target EC90 and exceeded reported exposure levels of many contemporary EGFR TKIs • At the steady state, trough Kp,uu of ~27% (CSF, primate) supports potential fo
Slide 6: Safety & tolerability: Phase 1 escalation / backfill experience
Safety & tolerability: Phase 1 escalation / backfill experience Safety TRAE TEAE • 3 DLTs were reported, at 80mg BID (Gr. 3 Population mucositis, bilirubin increased) and at 60mg (N=82) Any Gr Gr 1 Gr 2 Gr 3* Any Gr Gr 3+ BID (Gr. 3 mucositis) Any AE, n (%) 71 (87) 34 (41) 21 (26) 16 (20) 80 (98) 33
Slide 7: Anti-tumor activity: Phase 1 escalation / backfill experience
Anti-tumor activity: Phase 1 escalation / backfill experience • Responses and prolonged stable disease observed across diverse genotypes in this heavily pretreated cohort • Responses in patients with multiple EGFR mutations suggest effective targeting of on-target resistance !" D( !" )( !"#AABC#"DEF
Slide 8: Case examples: Confirmed responses observed across diverse previously treated molecular contexts
Case examples: Confirmed responses observed across diverse previously treated molecular contexts • 44 yo female, enrolled at 40mg BID • 68 yo female enrolled at 80mg QD • 51 yo male enrolled at 80mg BID • EGFR exon 19 deletion & C797S • EGFR L861Q previously treated with • EGFR exon 20 insertion wit
Slide 9: ctDNA response: Robust clearance of EGFR C797S and T790M
ctDNA response: Robust clearance of EGFR C797S and T790M Studying 27 patients with ctDNA-detected C797S or T790M on central plasma NGS, clearance was observed for 86% of C797S mutations (19 of 22) and 64% of T790M mutations (9 of 14) C797S VAF Change from Baseline T790M VAF Change from Baseline !" !
Slide 10: Confirmed responses in EGFR C797S-positive NSCLC across dose levels and driver mutations
Confirmed responses in EGFR C797S-positive NSCLC across dose levels and driver mutations blLA4#hP-KL blLA4#aILPOL: CL<O#blPRBL#-R#F4E#4f#aPIBLO#=L<-4R<#mno () • 32 patients from the target C797S *) !" D D D !" D !" !" !" D D population were response evaluable ) !" #" across escalation and expansion
Slide 11: Conclusions
Conclusions • Leveraging a novel macrocyclic scaffold, BH-30643 Expansion cohorts to inform Phase 2/3 development: demonstrated promising clinical activity against diverse EGFR genotypes and on-target resistance in heavily pretreated patients with advanced EGFR- TKI resistance mutant NSCLC • C797S d