Immunotherapy drug keytruda takes on mysterious cancers of unknown origin

NCT ID NCT03391973

Completed Disease control Sponsor: AHS Cancer Control Alberta Source: ClinicalTrials.gov ↗

First seen Jul 02, 2026 · Last updated Jul 02, 2026

Summary

This phase 2 trial is investigating whether the immunotherapy drug pembrolizumab (Keytruda) can help people with a rare and aggressive cancer called carcinoma of unknown primary (CUP), where doctors cannot find where the cancer started. Participants have not received prior treatment and have a poor prognosis. They receive pembrolizumab by IV every three weeks for up to 24 months. The study aims to see if the drug can shrink tumors or slow the disease.

What this could mean

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

Active substance: pembrolizumab (Keytruda)
What this could lead to: If it works, this could offer a new treatment option for people with a hard-to-treat cancer where the original site is unknown.
What could go wrong: This is a small, early-phase trial with no control group, so results may not apply broadly. Pembrolizumab can cause immune-related 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.

cancer of unknown primary site Neoplasms, Unknown Primary

As listed by the trial registrant

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

CARCINOMA OF UNKNOWN PRIMARY

Contacts and locations

Locations

Cross Cancer Institute

Edmonton, Alberta, Canada
Ottawa Hospital Cancer Centre

Ottawa, Ontario, Canada
Tom Baker Cancer Centre

Calgary, Alberta, T2N 4N2, Canada

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