Founder Behind a 4 Trillion Won Exit Takes Another Shot, Challenging Tagrisso Head-On

A drug designer who personally designed three FDA-approved targeted cancer therapies is taking on the global oncology market once again. BlossomHill Therapeutics, a San Diego-based oncology drug developer, has filed initial public offering (IPO) documents with the U.S. Securities and Exchange Commission (SEC). The company is led by Dr. J. Jean Cui, a serial entrepreneur who previously founded TurningPoint Therapeutics and sold it to Bristol Myers Squibb (BMS) for $4.1 billion (approximately 6.15 trillion won). Through a Nasdaq listing (ticker: BLSM), BlossomHill plans to raise approximately $125 million (approximately 170 billion won) and directly challenge AstraZeneca’s Tagrisso, which generates more than $7 billion (approximately 10.5 trillion won) in annual sales.

While at Pfizer, Dr. Cui designed Xalkori and Lorbrena, and after founding TurningPoint, she created Augtyro. Based on these achievements, she was also elected to the U.S. National Academy of Engineering (NAE) in 2024. Through February this year, BlossomHill had raised a total of $173 million (approximately 259.5 billion won) from investors including Colt Ventures and OrbiMed, with an estimated market capitalization of approximately $478 million (approximately 640 billion won).

■ BH-30643 Targets Patients With Tagrisso Resistance

BlossomHill’s lead pipeline candidate is BH-30643, a macrocyclic EGFR-targeted molecule. The company is currently conducting a phase 1/2 trial (SOLARA) in patients with non-small cell lung cancer (NSCLC). Tagrisso is a powerful first-line standard treatment, but its effectiveness is substantially limited when acquired resistance mutations such as C797S develop after treatment. BH-30643 is a multitargeted (OMNI-EGFR) inhibitor designed specifically to overcome these resistance mutations. Its key differentiators are that it does not target wild-type EGFR, potentially minimizing adverse effects such as skin rash, and that it has enhanced brain penetration.

Initial SOLARA data presented at the 2026 American Society of Clinical Oncology (ASCO) meeting were notable. The study recorded an objective response rate (ORR) of 59% in patients with NSCLC harboring various EGFR and HER2 mutations, including patients with brain metastases. In particular, 7 of 9 patients with the C797S mutation, a cause of Tagrisso resistance, showed a potent response, with variant allele frequency declining by more than 99%. The ASCO research team assessed BH-30643 as the first tyrosine kinase inhibitor (TKI) monotherapy to demonstrate a clinical response against C797S resistance mutations regardless of T790M mutation status. Dr. Alexander Spira of Virginia Cancer Specialists said, “It is encouraging that the drug preserves wild-type EGFR well, allowing administration of a sufficient dose to cross the blood-brain barrier without severe skin toxicity.” With the IPO proceeds, BlossomHill plans to hold an end-of-phase 1 meeting with the FDA in the fourth quarter of 2026 and discuss an accelerated approval pathway for specific patient groups with resistance.

■ Tagrisso Is Not the Only Competitor

The competitive landscape BlossomHill faces in the global lung cancer market is not simple. Tagrisso’s global market was approximately $4 billion to $6 billion in 2024-2025, but as its indications expand to include postoperative adjuvant therapy for patients with early-stage lung cancer, the market is projected to grow to approximately $13.2 billion (approximately 18 trillion won) by around 2032. Johnson & Johnson’s Rybrevant is also a formidable competitor. Rather than being used alone, the drug is used in combination with Lazcluze, the U.S. brand name for Leclaza, which was developed by Yuhan Corp. and licensed out. In the recent phase 3 MARIPOSA trial, the Rybrevant-plus-Lazcluze combination significantly improved overall survival (OS) and progression-free survival (PFS) compared with Tagrisso monotherapy, establishing it as a new global standard of care. BlossomHill must compete for global market share not only with Tagrisso but also with this combination therapy incorporating technology from South Korea.

The global SOLARA trial of BH-30643 (NCT06706076) is recruiting patients at institutions in South Korea, including Samsung Medical Center, as well as in the United States, Australia and Taiwan. The company’s second pipeline candidate, BH-30236, is a first-in-class drug targeting CDC-like kinases (CLK). It is currently in a phase 1/1b trial for patients with relapsed or refractory acute myeloid leukemia (AML) and high-risk myelodysplastic syndromes (MDS), and it does not yet have a direct competitor. BlossomHill also has BH-501284, a pan-KRAS inhibitor in the preclinical stage, and aims to enter clinical development in the first half of 2027. In the KRAS field, Daraxonrasib, developed by Revolution Medicines, is the leading candidate, with approval expected next year.

Industry observers view BH-30643 as having a strong possibility of becoming an M&A target for global big pharmaceutical companies once its phase 2 data take shape. Dr. Cui’s previous sale of TurningPoint to BMS for $4.1 billion, combined with the prospect of differentiated clinical data targeting Tagrisso-resistant patients with substantial unmet medical needs, could inevitably draw intense interest from major pharmaceutical companies. In the United States, as biotech companies including BozenaX, Atovia Therapeutics and Apnimed have recently filed a series of IPO applications, BlossomHill’s listing plans are also attracting attention.