New drug duo takes on Hard-to-Treat breast cancer

NCT ID NCT05266105

Ongoing Disease control Sponsor: Olema Pharmaceuticals, Inc. Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This early-stage trial tests a new drug called OP-1250 combined with an approved targeted therapy, palbociclib, in 60 adults with advanced or metastatic HR-positive, HER2-negative breast cancer. The goal is to find the safest dose and see if the combination can slow tumor growth. Participants must have cancer that has spread and not responded to prior treatments.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: Palazestrant (OP-1250) and palbociclib (Ibrance)
What this could lead to: If successful, this combination could offer a new treatment option for people with advanced hormone-positive breast cancer that has stopped responding to standard therapies.
What could go wrong: This is an early Phase 1 trial with only 60 participants, focused on safety and dosing. It is too small and early to know if the combination will work better than existing treatments, and side effects are still being identified.

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Conditions

The condition(s) this trial relates to.

breast cancer breast neoplasm hormone receptor-positive breast cancer

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

BREAST CANCER

Contacts and locations

Locations

Clinical Trial Site

Waratah, New South Wales, 2298, Australia
Clinical Trial Site

Westmead, New South Wales, 2145, Australia
Clinical Trial Site

South Brisbane, Queensland, 4101, Australia
Clinical Trial Site

Southport, Queensland, 4215, Australia
Clinical Trial Site

Clayton, Victoria, 3168, Australia
Clinical Trial Site

Frankston, Victoria, 3199, Australia
Clinical Trial Site

Geelong, Victoria, 3220, Australia
Clinical Trial Site

Nedlands, Western Australia, 6009, Australia

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