Virus injected into tumors shows promise in early breast cancer safety trial

NCT ID NCT05376527

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This early-stage trial tested a modified vaccinia virus (VV-GMCSF-Lact) injected directly into tumors of 34 women with recurrent or metastatic breast cancer that no longer responded to standard treatments. The main goal was to check safety and find the highest safe dose. Researchers monitored side effects, virus levels in blood, and any tumor response. Because this is a Phase 1 study, it focuses on safety, not on curing 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

modified vaccinia virus (VV-GMCSF-Lact) injected into tumors

What this could lead to

If successful, this could point toward a new treatment option for hard-to-treat metastatic breast cancer by using a virus to attack tumors from within.

What could go wrong

This is a very early Phase 1 safety trial with only 34 people. It is designed to find safe doses, not to prove effectiveness. The virus may cause side effects like fever or liver issues, and it may not shrink tumors.

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.

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Conditions

The condition(s) this trial relates to.

breast neoplasm metastatic malignant neoplasm vaccinia

As listed by the trial registrant

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

Contacts and locations

Locations

  • N.N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation

    Moscow, Russia, 115478, Russia

  • N.N. Petrov National Medical Research Center of Oncology

    Saint Petersburg, Russia, 197758, Russia

  • National Medical Research Radiological Centre (NMRRC) of the Ministry of Health of the Russian Federation

    Obninsk, Russia, 249036, Russia

  • Oncology Research Center, LLC

    Saint Petersburg, Russia, 197758, Russia