Biotech Startup KymaThera Raises $80M Series B Funding

KymaThera, a San Diego, CA-based provider of precision medicines for genetically defined diseases, has raised $80 million in a Series B funding round, led by Alta Partners, bringing the total amount to over $100 million.

The round also saw participation from Venrock, Foresite Capital, J. Wood Capital and others.

The company will use the funding to advance K-1728, an investigational oral PI3Kα inhibitor designed to target multiple PI3Kα mutations.

What is KymaThera?

KymaThera is a biotechnology company focused on developing precision medicines for diseases driven by specific genetic changes.

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The company uses a structure-based drug design platform to develop small-molecule medicines against well-characterized disease targets.

Its lead drug candidate, K-1728, is an oral and pan-mutant selective PI3Kα inhibitor. KymaThera is initially developing it for HR+/HER2- breast cancer and PI3Kα-driven vascular malformations.

For breast cancer, the company plans to study K-1728 both as a standalone treatment and in combination with other therapies. For vascular malformations, it is being developed as a standalone treatment.

How Much Funding Has KymaThera Raised?

KymaThera has raised $80 million in its latest Series B funding round.

The funding brings the company’s total funding to more than $100 million.

Who Invested in KymaThera’s Series B Round?

The $80 million Series B round was led by Alta Partners.

Other participating investors include:

• Venrock
• Foresite Capital
• J. Wood Capital
• Other investors

Why the Funding Matters

KymaThera will use the new funding to advance K-1728 into clinical development.

The company expects to begin patient dosing in a Phase 1 clinical study in the fourth quarter of 2026. The financing is expected to support the program through its initial clinical proof-of-concept.

KymaThera is targeting HR+/HER2- breast cancer, where the company sees continued unmet treatment needs, as well as PI3Kα-driven vascular malformations, where systemic treatment options remain limited.

Who founded KymaThera?

KymaThera was founded in 2024 by Rob Kania and Jason M. Cox.

The company is headquartered in San Diego, California.

"PI3Kα is one of the most important, well-validated, and heavily pursued disease drivers in oncology, but its therapeutic potential has been constrained by wild-type PI3Kα-mediated toxicity and incomplete coverage of clinically relevant mutations," said Rob Kania, Ph.D., Chief Executive Officer of KymaThera.

"I invest in people, and KymaThera has assembled an outstanding team with deep experience in drug discovery and development," said Bob More, Partner at Alta Partners. "Drug development is hard, and great people find ways to solve hard problems.

Market and Business Growth

In preclinical and IND-enabling studies, K-1728 showed activity against both kinase and helical domain PI3Kα mutations.

The drug candidate produced tumor regressions at low, once-daily doses in models carrying both mutation types. It also showed a wide preclinical therapeutic window between exposures linked to tumor regression and those associated with hyperglycemia.

These results support the company’s plans to advance K-1728 into clinical testing.

What Happens Next?

KymaThera plans to begin patient dosing in a Phase 1 study of K-1728 in the fourth quarter of 2026.

The company will focus on advancing the drug candidate through early clinical development, with the latest financing expected to support the program through initial clinical proof-of-concept.

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