Ad-hCMV-Flt3L

Undergo standard of care tumor resection

22MAY2026- Inclusion criteria updated to correct a typographical error regarding serum albumin.

This phase I trial tests the safety, side effects and best dose of AdV-HSV1-TK and AdV-Flt3L in combination with valacyclovir for the treatment of patients with primary cancerous (malignant) brain tumors that can be removed by surgery (resectable) and that have come back after a period of improvement (recurrent).

AdV-HSV1-TK and AdV-Flt3L use a virus modified in the laboratory to kill tumor cells and stimulate the immune system to recognize the tumor cells as "invaders" which can lead to tumor shrinkage. For this process to work, an oral anti-herpes medication called valacyclovir is also needed. Giving AdV-HSV1-TK, AdV-Flt3L and valacyclovir may be safe, tolerable and/or effective in treating patients with resectable, recurrent primary malignant brain tumors.

Live record on ClinicalTrials.gov →

• Age 3 to 25 years with:
• Diagnosis of malignant primary brain tumor after tumor recurrence, relapse, or progression who have completed up-front, standard-of-care therapy
• Age 26 to 39 years with:
• Diagnosis of diffuse hemispheric glioma, H3 G34-mutant, per 2021 World Health Organization (WHO) classification, after tumor recurrence, relapse, or progression who have completed up-front, standard-of-care therapy
• At least 10 kg (and body surface area \[BSA\] \> 0.5 m\^2)
• Participants who are receiving corticosteroids must be on a stable or decreasing dose for at least 3 days prior to baseline MRI

Inclusion criteria as written on the registry, trimmed. The full list, with exclusions, is on the live record.