KymaThera has raised an $80 million Series B financing to push K-1728, an oral pan-mutant selective PI3Kα inhibitor, into the clinic. The San Diego biotech announced the round on 6 October 2026, led by Alta Partners with participation from existing investors Venrock and Foresite Capital and new investor J. Wood Capital — bringing the two-year-old company's total funding past $100 million and setting up a Phase 1 trial the company expects to begin dosing in the fourth quarter of 2026.
K-1728 in four numbers
Figures from the 6 October 2026 announcement.
Alta Partners’ bet on K-1728
KymaThera’s two rounds
- 2024
KymaThera founded
Launched in San Diego under CEO Rob Kania, Ph.D., applying structure-based drug design to PI3Kα as its first target.
- 2024
Series A closes
A $20 million round co-led by Foresite Capital and Venrock funds K-1728's preclinical development.
- 6 October 2026
$80 million Series B announced
Led by Alta Partners, with Venrock and Foresite Capital returning and J. Wood Capital joining as a new investor; total funding passes $100 million.
- Q4 2026
Phase 1 dosing targeted
KymaThera expects to begin dosing patients in a Phase 1 study evaluating K-1728.
KymaThera was founded in 2024 around a single mechanism: PI3Kα, a signaling node already validated by three approved cancer drugs, but one the company believed existing medicines addressed too narrowly. A $20 million Series A, co-led by Foresite Capital and Venrock, funded the preclinical work behind K-1728. The $80 million Series B announced on 6 October 2026 is meant to carry that bet into patients, funding K-1728 through an initial clinical proof-of-concept in both of the diseases the company is pursuing.
“We designed K-1728 from the outset to address key limitations of earlier PI3Kα approaches.” Rob Kania, Ph.D., CEO, KymaThera — 6 October 2026 announcement
Beyond a single hotspot mutation
PI3Kα is already a proven cancer target: KymaThera is entering a field where alpelisib (Piqray, approved 2019) and inavolisib (Itovebi) are both approved for HR-positive, HER2-negative breast cancer carrying PIK3CA mutations, matched to patients by a companion diagnostic. Those drugs are built around specific hotspot mutations in the PIK3CA gene — the mutations the pivotal trials enrolled and the labels now specify. KymaThera says K-1728 is designed differently: as a pan-mutant inhibitor, active against the broader range of PI3Kα alterations found across tumor types, not only the hotspots its predecessors were built around.
The same signaling pathway also drives a distinct set of diseases: PIK3CA-related vascular malformations, in which the identical class of mutations causes abnormal growth of blood and lymphatic vessels rather than tumors. KymaThera is developing K-1728 for both, which is unusual — most PI3Kα programs have been built for oncology alone.
What makes K-1728 different
Pan-mutant, not single-hotspot
Alpelisib and inavolisib are approved for specific PIK3CA hotspot mutations identified by a companion diagnostic. KymaThera says K-1728 is designed to inhibit the broader range of PI3Kα mutations found in tumors, not only those hotspots.
One mechanism, two diseases
K-1728 is being developed for PI3Kα-mutant cancers and for vascular malformations, conditions that share the same overactive signaling but have mostly been pursued as separate drug-development problems.
A repeat-investor syndicate
Alta Partners led the Series B with both Series A investors, Venrock and Foresite Capital, returning alongside new investor J. Wood Capital — the kind of follow-on backing venture firms reserve for science they already know.
The market alpelisib already proved
PI3K inhibitors are already a commercial category, not a speculative one: alpelisib's 2019 approval and inavolisib's launch since have established that payers and prescribers will use a PI3Kα inhibitor once a patient's tumor is matched to it by testing. The open question for K-1728 is how much of the market a pan-mutant drug can reach beyond the hotspot-restricted population those diagnostics currently identify.
PI3K inhibitors, sized to 2030
$1.56B → $2.88B
PI3K inhibitors market, 2025 to 2030, as forecast by The Business Research Company (2026).
Sources: The Business Research Company, Phosphoinositide 3-Kinase (PI3K) Inhibitors Global Market Report
Regulatory News outlook
With K-1728 still a year or more from its first clinical data, we treat any specific revenue figure as illustrative only: even a 10% share of the forecast 2030 PI3K-inhibitor market would put a single pan-mutant entrant near $288 million in peak-year sales, a useful yardstick rather than a prediction.
How we got here: 10% of The Business Research Company's $2.88 billion 2030 PI3K-inhibitor forecast, chosen as an illustrative share only; K-1728 has not yet dosed a patient, so no outcome-based estimate is possible yet.
K-1728 against the approved field
| Product | Target | Mutation scope | Indication | Status |
|---|---|---|---|---|
| K-1728 (KymaThera) | PI3Kα | Pan-mutant (designed for the broader range of PI3Kα alterations) | PI3Kα-mutant cancers; PIK3CA-related vascular malformations | Preclinical; Phase 1 dosing targeted Q4 2026 |
| Alpelisib / Piqray (Novartis) | PI3Kα | Specific PIK3CA hotspot mutations | HR+/HER2- breast cancer, with fulvestrant | FDA approved, 2019 |
| Inavolisib / Itovebi (Genentech) | PI3Kα | PIK3CA-mutated | HR+/HER2- breast cancer, with palbociclib and fulvestrant | FDA approved |
| Capivasertib / Truqap (AstraZeneca) | AKT (same pathway) | PIK3CA, AKT1 or PTEN alterations | HR+/HER2- breast cancer, with fulvestrant | FDA approved |
From each company's own labelling and announcements; not a clinical comparison.
The road to a first dose
KymaThera has not yet published preclinical data on K-1728, and the company's pan-mutant claim has not been tested in patients. The Series B is explicitly structured to change that: the company says the new funding carries K-1728 through an initial Phase 1 proof-of-concept across both of its target indications, with dosing targeted to begin in the fourth quarter of 2026.
- Phase 1 dosing: targeted for the fourth quarter of 2026, the company's first clinical readout for K-1728.
- Two indications in parallel: PI3Kα-mutant cancers and PIK3CA-related vascular malformations, both funded from the same round.
- Runway: the Series B is intended to fund development through initial clinical proof-of-concept, though KymaThera has not disclosed a specific cash runway in months or years.
What is not yet public: K-1728's preclinical pharmacology and safety data, the specific trial design and enrollment criteria for the Phase 1 study, and any regulatory designation the program may or may not have received. We will update this page as KymaThera discloses more.
Sources & further reading
- KymaThera, “KymaThera Announces $80 Million Series B Financing to Advance K-1728, a Next-Generation Pan-Mutant Selective PI3Kα Inhibitor, for Cancer and Vascular Malformations,” press release, 6 October 2026. prnewswire.com
- Endpoints News, “KymaThera, Rouge raise VC funding; Vaxcyte, Spyre do public offerings,” 6 October 2026. endpoints.news
- Pharmaceutical Technology, “KymaThera pulls in $80m to bring breast cancer drug to clinic.” pharmaceutical-technology.com
- Pharma Journalist, “KymaThera Raises $80M to Advance PI3Kα Cancer Drug,” quoting CEO Rob Kania, Ph.D. pharmajournalist.com
- AACR, “Inavolisib Regimen Approved for Certain Treatment-resistant Breast Cancers.” aacr.org
- The Business Research Company, “Phosphoinositide 3-Kinase (PI3K) Inhibitors Global Market Report.” thebusinessresearchcompany.com
Regulatory News reports on public regulatory documents. It is not legal advice, and the primary sources above govern. If we have made an error, we will say so in public: see corrections.
Frequently asked questions
What did KymaThera raise, and when?
An $80 million Series B financing, announced 6 October 2026, led by Alta Partners with participation from existing investors Venrock and Foresite Capital and new investor J. Wood Capital. It brings KymaThera's total funding to more than $100 million since its 2024 founding.
What is K-1728?
An oral, pan-mutant selective PI3Kα inhibitor. KymaThera says it is designed to act across the broader range of PI3Kα mutations found in tumors, rather than the specific hotspot mutations existing approved PI3Kα inhibitors target. The company is developing it for both PI3Kα-mutant cancers and vascular malformations.
Is K-1728 in clinical trials yet?
No. KymaThera expects to begin dosing patients in a Phase 1 clinical study during the fourth quarter of 2026. The Series B is intended to fund development through initial clinical proof-of-concept.
Is KymaThera publicly traded?
No. KymaThera is a privately held company; this financing is a venture round, not a public offering.
