KymaThera Announces $80 Million Series B Financing to Advance K-1728, a Next-Generation Pan-Mutant Selective PI3Kα Inhibitor, for Cancer and Vascular Malformations

– Series B financing led by Alta Partners with participation from Series A co-leads Venrock and Foresite Capital, new investor J. Wood Capital and others –

– K-1728 is designed to selectively inhibit both kinase domain and helical domain PI3Kα mutations while sparing wild-type PI3Kα –

– Phase 1 patient dosing expected to begin in the fourth quarter of 2026 –

SAN DIEGO, Oct. 6, 2026 /PRNewswire/ -- KymaThera, a biotechnology company developing next-generation precision medicines for genetically defined diseases, today announced the closing of an $80 million Series B financing led by Alta Partners, with participation from Venrock, Foresite Capital, J. Wood Capital and others. Proceeds from the financing will primarily support the advancement of K-1728, KymaThera's investigational, oral, pan-mutant selective PI3Kα inhibitor. This financing follows the Series A, co-led by Foresite Capital and Venrock in 2024, and brings KymaThera's total capital raised to more than $100 million.

KymaThera is initially developing K-1728 as a monotherapy and in combination regimens for HR+/HER2- breast cancer, where substantial unmet need remains despite available therapies, and as a monotherapy for PI3Kα-driven vascular malformations. Vascular malformations are serious, often debilitating conditions for which systemic treatment options remain limited. The company expects to initiate patient dosing in a Phase 1 study in the fourth quarter of 2026, with the financing expected to fund development through initial clinical proof-of-concept.

"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. Rob and his team have the experience, scientific rigor and determination to take on an important challenge with K-1728, and I'm thrilled to support them as they advance the company and move the program into the clinic."

"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. "Our drug design objective from the outset was to address these limitations. K-1728 possesses class-leading potency with helical mutant selectivity windows wider than any reported to date. This financing, backed by an exceptional syndicate of leading life sciences investors, gives us the resources to rapidly advance K-1728 into the clinic and pursue its potential across cancer and vascular malformations."

In preclinical and IND-enabling studies, K-1728 demonstrated potent activity against both kinase and helical domain PI3Kα mutations, driving tumor regressions at low, once-daily doses in models harboring both mutation classes. K-1728 also demonstrated a wide preclinical therapeutic window between exposures associated with deep tumor regressions and those associated with hyperglycemia. These data support a differentiated pan-mutant profile and the advancement of K-1728 into clinical development.

"When we made our Series A investment in KymaThera, we saw an experienced team with a rigorous scientific approach to building differentiated medicines against highly validated targets. K-1728, internally discovered and wholly owned by KymaThera, is an impressive result," said Michael Rome, Ph.D., Managing Director at Foresite Capital. "What the team has accomplished in just two years has strengthened our conviction in both their approach and their ability to execute, and we are excited to continue supporting the company as it enters the clinic," said Mariana Mihalusova, Ph.D., Partner at Venrock.

About K-1728

K-1728 is an investigational, oral, pan-mutant selective PI3Kα inhibitor designed to potently inhibit disease-driving kinase and helical domain mutations while sparing wild-type PI3Kα. KymaThera designed K-1728 using its structure-based drug discovery capabilities to address limitations of earlier generations of PI3Kα inhibitors. Preclinical studies have demonstrated antitumor activity across multiple PI3Kα-mutant models and a differentiated preclinical therapeutic window. KymaThera plans to develop K-1728 across PI3Kα-mutant cancers and vascular malformations.

About KymaThera

KymaThera is a biotechnology company focused on discovering and developing precision medicines against well-characterized targets that drive human disease. KymaThera applies a proprietary structure-based drug design platform built on the team's decades of drug discovery experience to create differentiated small-molecule therapeutics where scientific precision can achieve meaningful improvements over current therapies. KymaThera's lead program is advancing K-1728 to treat PI3Kα-mutant cancers and vascular malformations. KymaThera is also advancing earlier-stage discovery programs against additional validated disease targets.

For more information, visit kymathera.com and engage with us on LinkedIn.

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SOURCE KymaThera