Experimental immune cell combo for tough breast cancer stalls after just 2 patients

NCT ID NCT05385705

First seen Jun 24, 2026 · Last updated Jun 26, 2026 · Updated 2 times

Summary

This early-phase trial tested whether adding donor natural killer (NK) cells to the standard antibody drugs trastuzumab and pertuzumab could help people with advanced HER2-positive breast cancer that had stopped responding to other treatments. Only 2 participants were enrolled before the study was terminated, so no conclusions can be drawn about safety or effectiveness. The goal was to see if the NK cells could boost the immune system's ability to attack the cancer.

What this could mean

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

Active substance

donor natural killer (NK) cells combined with trastuzumab and pertuzumab

What this could lead to

If it worked, this approach might improve how well the immune system attacks HER2-positive breast cancer that has stopped responding to other treatments.

What could go wrong

This was a very early (Phase 1) safety study that was terminated after only 2 people enrolled, so we have no data on whether it works or is safe. The combination also carries risks like infusion reactions and immune-related side effects.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

Get updates

Get notified about this study

Sign up to get updates when this study changes or when new studies for BREAST NEOPLASMS are added.

Our safety recommendation!

By submitting, you agree to our Terms of use

Conditions

The condition(s) this trial relates to.

breast neoplasm HER2 positive breast carcinoma

As listed by the trial registrant

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

Contacts and locations

Locations

  • Hospital del Mar

    Barcelona, 08003, Spain

  • Vall d'Hebron Hospital

    Barcelona, 08035, Spain