Stipple Bio Raises $100M to Advance Precision Oncology Pipeline

The biotech startup's Series A funding will support early clinical trials for lead candidate STP-100 and expand its Pointillist Platform for tumor-specific epitope discovery.

Apr. 6, 2026 at 1:11pm

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Stipple Bio, a private biotechnology company focused on developing targeted cancer therapies, has raised $100 million in a heavily oversubscribed Series A financing. The round was co-led by RA Capital, a16z Bio+Health, and Nextech Invest, with participation from existing investors including Emerson Collective Investments, GV, LoLa Capital Partners, and GordonMD Global Investments. The funding will advance Stipple Bio's lead candidate, STP-100, into early-stage clinical trials and further develop the company's Pointillist Platform for identifying tumor-specific cell surface epitopes.

Why it matters

Stipple Bio's approach to precision oncology aims to improve therapeutic index by targeting tumor-specific epitopes, which could unlock new druggable targets and lead to more effective and safer cancer treatments. The company's Pointillist Platform represents a novel strategy in the field of precision medicine, moving beyond just targeting tumor-specific gene expression to focus on the unique molecular signatures on cancer cell surfaces.

The details

Stipple Bio was founded in 2022 by cancer biology experts Dr. Aaron Ring and Dr. Aashish Manglik, who believed that targeting tumor-specific cell surface epitopes could improve therapeutic index and unlock previously intractable oncology targets. The company's lead candidate, STP-100, is a novel Antibody Drug Conjugate (ADC) designed to avoid on-target/off-tumor toxicity. With the Series A funding, Stipple Bio plans to advance STP-100 into multiple early-stage clinical studies and leverage its Pointillist Platform to identify additional tumor-specific targets for its precision oncology pipeline.

  • Stipple Bio was founded in 2022.
  • The Series A financing closed in April 2026.
  • STP-100 is expected to enter clinical studies in early 2027.

The players

Stipple Bio

A private biotechnology company focused on developing targeted cancer therapies by leveraging its Pointillist Platform to identify tumor-specific cell surface epitopes.

Dr. Aaron Ring

Co-founder of Stipple Bio and Associate Professor in the Translational Science and Therapeutics Division at Fred Hutch.

Dr. Aashish Manglik

Co-founder of Stipple Bio and Associate Professor in the Pharmaceutical Chemistry department at UCSF.

RA Capital

A leading healthcare-focused investment firm that co-led Stipple Bio's Series A financing.

a16z Bio+Health

The biotech and healthcare investment arm of Andreessen Horowitz, which co-led Stipple Bio's Series A financing.

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What they’re saying

“We are building upon deep cancer biology expertise to map, target and unlock tumor-specific epitopes which enable us to develop a pipeline of next-generation precision oncology therapeutics.”

— Jeff Landau, Chief Executive Officer of Stipple Bio

“Clinical experience with prior antibody drugs has taught us that epitope-level specificity matters. Since the earliest days of Stipple Bio, we've been impressed by the team's vision to move beyond tumor-specific gene expression and to pioneer tumor-specific 'epitomics' in precision oncology.”

— Vineeta Agarwala, General Partner at Andreessen Horowitz and lead investor for the a16z Bio+Health Fund

“Stipple Bio's Pointillist Platform introduces an epitope-level approach to targeting tumor biology that has the potential to meaningfully expand the set of druggable oncology targets. Lead candidate STP-100 illustrates how this strategy can drive precise tumor targeting while sparing normal tissues—a key step toward improving therapeutic index in ADCs.”

— Derek DiRocco, Partner at RA Capital Management

What’s next

Stipple Bio plans to advance its lead candidate, STP-100, into multiple early-stage clinical studies in the coming years.

The takeaway

Stipple Bio's innovative approach to precision oncology, focused on targeting tumor-specific cell surface epitopes, has attracted significant investor interest and funding. If successful, the company's Pointillist Platform could lead to more effective and safer cancer treatments by unlocking new druggable targets.