Experimental drug RMC-5552 tested in recurrent glioblastoma – early trial ends

NCT ID NCT05557292

Terminated Disease control Sponsor: Nicholas Butowski Source: ClinicalTrials.gov ↗

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

Summary

This early-phase trial tested the drug RMC-5552 in 7 adults with glioblastoma that had returned after standard treatment. The drug works by blocking a protein called mTOR, which may help stop cancer cells from growing. The study aimed to find the safest dose and check for side effects, but it was terminated early, so results are limited.

What this could mean

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

Active substance: RMC-5552 (a drug that blocks a protein called mTOR, which may slow cancer growth)
What this could lead to: If successful, this could point toward a new treatment option for recurrent glioblastoma, a difficult-to-treat brain cancer.
What could go wrong: This was a very early, small trial (only 7 people) that was terminated, so results are limited. The drug may not work or could have side effects.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

glioblastoma

As listed by the trial registrant

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

GLIOBLASTOMA RECURRENT GLIOBLASTOMA

Contacts and locations

Locations

University of California, San Francisco

San Francisco, California, 94143, United States

More trials for these conditions

Other studies related to the condition(s) this trial covers.