Interim clinical data for the oncolytic virus product MVR-T3011 has shown significant efficacy, particularly at a higher dose level, in patients with high-risk, Bacillus Calmette-Guerin (BCG)-unresponsive non–muscle invasive bladder cancer (NMIBC). The results were presented at the 2025 Annual Meeting of the Society of Urologic Oncology.
Patients in both papillary and carcinoma in situ (CIS) cohorts demonstrated positive responses at 3 and 6 months. The treatment also exhibited a favorable safety and tolerability profile. The data, current as of September 19, 2025, are from a phase 2 interventional study (NCT06971614).
The trial revealed a promising efficacy profile, with notably high response rates observed at the 1×10¹⁰ PFU dose level across both patient groups.
In the papillary NMIBC cohort, 26 patients were enrolled, with 16 receiving the lower dose and 10 the higher dose. Three-month recurrence-free survival (RFS) was 87.1% at the 2×10⁹ PFU dose and 100% at 1×10¹⁰ PFU. Six-month RFS was 80.4% and 100%, respectively. At nine months, RFS was 80.4% for the lower dose and was not reached for the higher dose. Twelve-month RFS was 71.4% at the lower dose and also not reached at the higher dose.
Among 12 patients with CIS NMIBC (with or without Ta/T1), 7 received the lower dose and 5 the higher dose. The 3- and 6-month complete response rates (CRR) were 71.4% at 2×10⁹ PFU and 100% at 1×10¹⁰ PFU across both dose levels.
The safety profile of MVR-T3011 remained consistent with previous findings. Most treatment-emergent adverse events (TEAEs) were grade 1 or 2. Five grade 3 TEAEs were reported, two of which were treatment-related and consistent with catheterization procedures. No dose-limiting toxicities or grade 4 or higher TEAEs occurred.
MVR-T3011 is a replication-competent, tumor-lytic Herpes Simplex Virus 1 (HSV-1) based oncolytic immunotherapy featuring a proprietary 3-in-1 design. It integrates an anti-PD-(L)1 antibody and interleukin-12 (IL-12) within the HSV-1 backbone, allowing simultaneous tumor cell lysis and stimulation of both innate and adaptive immune responses. The product is adaptable to multiple administration routes, including intratumoral, intracavitary, and intravenous.
Notably, MVR-T3011 is the first HSV-1-based oncolytic immunotherapy to complete a phase 1 trial via systemic intravenous dosing under the FDA regulatory framework.
The development of MVR-T3011 targets the urgent unmet need in high-risk NMIBC treatment, where BCG remains the standard of care. However, a global shortage of BCG exists, with the US supply meeting less than 30% of demand, underscoring the need for novel therapies.
ImmVira, the trial sponsor, launched the phase 2 trial for BCG-unresponsive high-risk NMIBC in the US in June 2025 and is advancing a global multi-regional trial including China.
Grace Zhou, MD, chairwoman and CEO of ImmVira, stated, “We are highly encouraged by the interim efficacy data, especially the high complete response and recurrence-free survival rates for both BCG-unresponsive CIS and papillary patients at 1×10¹⁰ PFU. We believe MVR-T3011 could emerge as the next generation of therapy for patients with high-risk, BCG-unresponsive NMIBC.”
Reference: ImmVira news release, December 4, 2025.
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