BridgeBio Oncology Therapeutics, a company working to advance the field of therapies addressing a validated but elusive group of cancer targets, has reached a deal to go public in a SPAC merger that brings more than $450 million to support clinical testing of three drug candidates.
The merger agreement announced Friday is with Helix Acquisition Corp. II, a SPAC sponsored by affiliates of Cormorant Asset Management. When the deal closes, the combined company will take the BridgeBio Oncology Therapeutics name and is expected to trade on the Nasdaq under the stock symbol “BBOT.”
BridgeBio Oncology spun out of BridgeBio Pharma last year, backed by $200 million in financing led by Cormorant. The biotech aims to improve on current approaches to RAS, a family of proteins that act like an on/off switch to regulate cell growth. Mutated versions of these signaling proteins drive cancer proliferation. Amgen’s Lumakras and Bristol Myers Squibb’s Krazati (from Mirati Therapeutics), which address a specific mutation called KRAS G12C, have FDA approvals in colorectal and non-small cell lung cancer. Both small molecule drugs work by targeting KRAS G12C when it is in the “off” state, locking the mutated protein in this inactive form.
BridgeBio Oncology aims to drug KRAS G12C in both the “on” and “off” states with a drug codenamed BBO-8520. A Phase 1 study is testing this drug in patients with non-small cell lung cancer. Preliminary data for BBO-8520, as a monotherapy and in combination with Merck immunotherapy Keytruda, are expected in the second half of 2025.
A second drug candidate, BBO-10203, blocks the interaction between RAS and PI3K alpha, a family of enzymes involved in cellular growth and proliferation. While PI3K alpha inhibitors have reached the market, BridgeBio Oncology aims to offer a better safety profile. A Phase 1 test is underway evaluating BBO-10203 in advanced cases of breast cancer, colorectal cancer, and non-small cell lung cancer. The third drug, BBO-11818, is a pan-KRAS inhibitor targeting mutant versions KRAS proteins in both the “on” and “off” states. BridgeBio Oncology says this molecule is designed to offer potency against KRAS G12D and KRAS G12V mutations; dosing of the first patient is expected in the first half of this year.
In an investor presentation, Helix said the ability to target many types of KRAS G12mutation-driven cancers creates opportunities for drug combinations, treatment across the various stages of cancer, and revenue from multiple drugs. BridgeBio Oncology has a large market opportunity with about 250,000 patients diagnosed annually in the U.S. across the target indications of breast, lung, colorectal, and pancreatic cancers, according to the presentation.
“The company’s pipeline has the potential for paradigm-shifting impact on the treatment of some of the highest prevalence malignancies and we look forward to seeing patient impact further materialize as the clinical trials move forward,” Bihua Chen, founder and CEO of Cormorant and CEO of Helix, said in a prepared statement.
BridgeBio Oncology faces competition from other companies trying to develop next-generation KRAS inhibitors. Revolution Medicines expects data readouts this year for the KRAS G12D inhibitor zodronrasib and the KRAS G12C inhibitor elironrasib. Both drugs are in early clinical development as monotherapies and as part of combination treatments for solid tumors. Frontier Medicines’ lead program, FMC-376, inhibits KRAS G12C in both its active and inactive states. A Phase 1/2 test is ongoing. As for Bristol Myers Squibb, the Mirati acquisition that brought Krazati included another drug candidate in early clinical development for KRAS G12D-mutated solid tumors. Meanwhile, Astellas Pharma’s approach to KRAS G12D degrades the target protein.
BridgeBio Oncology brings to the Helix merger about $100 million in cash. That money will be combined with $196 million of Helix’s own funds. The newly public company will raise additional capital from a group of institutional investors, led by Cormorant, who have committed to purchase BridgeBio Oncology shares priced at $10.36 each to raise another $260 million. The cash is expected to provide enough runway to last into 2027, according to the investor presentation.
The boards of directors of BridgeBio Oncology and Helix have approved the proposed merger, which is expected to be completed in the third quarter of this year. The transaction still needs shareholder approvals.
Illustration: Getty Images
