BlossomHill Therapeutics Prices Upsized $150M IPO at $16 for EGFR NSCLC Programs

BlossomHill Therapeutics (BLSM) priced its upsized initial public offering at $16.00 per share, selling 9,375,000 shares for $150 million in gross proceeds. Shares begin trading on the Nasdaq Global Select Market today, August 7, under the ticker BLSM. Underwriters led by J.P. Morgan, Leerink Partners, and Guggenheim have a 30-day option for up to 1,406,250 additional shares.

The raise was upsized from an initial $125 million target. The $16 final price sits at the midpoint of the $15-$17 range. BlossomHill is one of two biotech IPOs debuting today, alongside Latigo Biotherapeutics ($345.6 million), bringing August’s biotech IPO total to more than $1.1 billion across four companies including Braveheart Bio and Attovia Therapeutics.

The San Diego-based company is advancing two clinical-stage oncology programs. The lead asset, BH-30643, is a non-covalent macrocyclic OMNI-EGFR inhibitor designed to be mutant-selective. It targets EGFR kinase domain mutations while sparing wild-type EGFR, potentially reducing the dose-limiting toxicities that constrain earlier-generation TKIs like Tagrisso. Standard EGFR inhibitors bind to the ATP-binding pocket and are overcome by secondary mutations; BH-30643’s macrocyclic structure is engineered to maintain binding across a broader range of resistance mutations. BH-30643 is currently in the Phase 1/2 SOLARA trial (NCT06706076) for patients with locally advanced or metastatic NSCLC harboring EGFR or HER2 mutations.

The second program, BH-30236, is a CLK inhibitor targeting relapsed/refractory acute myeloid leukemia and high-risk myelodysplastic syndromes. The hematologic malignancy space has few targeted options but carries a higher risk of single-agent failure than biomarker-driven solid tumor programs.

The risk is straightforward: both programs are Phase 2 at best. BH-30643’s SOLARA trial is dose-escalation with backfill cohorts — early, not registrational. The company has roughly two to three years of cash runway at current burn rates before needing additional financing or a partnership. The EGFR TKI market is crowded, with Tagrisso (osimertinib) dominating first-line and Rybrevant (amivantamab) establishing a foothold in later lines. BlossomHill must show clinically meaningful responses in Tagrisso-resistant patients to justify a registrational path.

What to watch next: SOLARA Phase 1 data, expected at a medical meeting, and any signs that BH-30643’s mutant-selectivity profile translates to better tolerability than existing EGFR inhibitors in resistant patients.