Aprea Therapeutics Highlights Early Tumor Shrinkage, Clean Safety for APR-1051

Biotech company presents data on its lead WEE1 inhibitor program at Oppenheimer conference

Mar. 3, 2026 at 3:47am

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Aprea Therapeutics highlighted early clinical activity and a tolerability profile it believes could differentiate its lead WEE1 inhibitor program, APR-1051, during an Oppenheimer-hosted presentation. The company said its strategy centers on precision oncology, matching therapies to biomarker-defined patient populations. Aprea's study is not an all-comers trial, with patients eligible based on the presence of specific biomarkers and mutations, including CCNE1, CCNE2, FBXW7, PPP2R1A, KRAS/p53, and HPV status. The company focused on PPP2R1A, FBXW7, and HPV-positive cancers, and said the first response was observed at the 150 mg dose, which it is treating as the 'minimum efficacious dose'.

Why it matters

Aprea's lead program, APR-1051, is a next-generation WEE1 inhibitor that the company believes could differentiate itself from prior efforts in the class, which have demonstrated biological activity but suffered from a narrow therapeutic window. The company's precision oncology approach aims to match therapies to specific biomarker-defined patient populations, rather than using broadly cytotoxic chemotherapy.

The details

Aprea's study is not an all-comers trial, with patients eligible based on the presence of specific biomarkers and mutations, including CCNE1, CCNE2, FBXW7, PPP2R1A, KRAS/p53, and HPV status. The company focused on PPP2R1A, FBXW7, and HPV-positive cancers, and said the first response was observed at the 150 mg dose, which it is treating as the 'minimum efficacious dose'. At 150 mg and 220 mg, two patients showed partial responses on first scans, each with a 50% reduction in target lesions and approximately 90% reduction in a biomarker, with 'very minimal' drug-related adverse effects. Aprea has completed enrollment in the 220 mg cohort and is waiting to move to 300 mg. The company plans to enrich for PPP2R1A, colorectal cancer, and HPV-positive patients.

  • Aprea expects to complete dose escalation by Q3 2026.

The players

Aprea Therapeutics

A clinical-stage biopharmaceutical company dedicated to developing targeted therapies that restore tumor suppressor function in cancers driven by TP53 mutations.

Dr. Oren Gilad

The CEO of Aprea Therapeutics who presented the data on the company's lead WEE1 inhibitor program, APR-1051, at the Oppenheimer conference.

Merck

A pharmaceutical company that previously developed the WEE1 inhibitor MK-1775 (later AZD-1775), which Aprea's CEO said demonstrated biological activity but ultimately suffered from a narrow therapeutic window.

AstraZeneca

A pharmaceutical company that later terminated development of the WEE1 inhibitor MK-1775 (AZD-1775) and is pursuing an analog where the therapeutic window is still being defined.

Zentalis

A biopharmaceutical company that is using a '5-on, 2-off' schedule with its WEE1 inhibitor approach.

Debiopharm

A biopharmaceutical company whose WEE1 inhibitor did not show single-agent activity and has been associated with QT prolongation, according to Aprea's CEO.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident

“Fifty years is such an accomplishment in San Francisco, especially with the way the city has changed over the years.”

— Gordon Edgar, grocery employee

The takeaway

Aprea's lead WEE1 inhibitor program, APR-1051, is showing promising early clinical activity and a tolerability profile that the company believes could differentiate it from prior efforts in the class. The company's precision oncology approach, focusing on biomarker-defined patient populations, aims to improve upon the narrow therapeutic window seen with other WEE1 inhibitors.