MVR-T3011 Yields Efficacy and Safety in BCG-Unresponsive NMIBC

Interim clinical data for the oncolytic virus product, MVR-T3011, demonstrated significant efficacy, particularly at a higher dose level, in a study of patients with high-risk, Bacillus Calmette-Guerin (BCG)-unresponsive non–muscle invasive bladder cancer (NMIBC). Data were announced and presented at the 2025 Annual Meeting of the Society of Urologic Oncology.¹

Patients in both papillary and carcinoma in situ (CIS) cohorts showed positive responses at the 3- and 6-month marks. The treatment also exhibited a favorable safety and tolerability profile. The data, current as of September 19, 2025, covered the phase 2 interventional study (NCT06971614).²

The trial data demonstrates a promising efficacy profile, with notably high response rates observed at the 1x10¹⁰ PFU dose level across both patient cohorts.¹

A total of 26 patients with papillary NMIBC were enrolled, with 16 receiving the lower dose and 10 receiving the higher dose. The 3-month recurrence-free survival (RFS) in patients at the 2x10⁹ PFU dose level was 87.1% vs 100% at the 1x10¹⁰ PFU dose level. The 6-month RFS at both dose levels was 80.4% vs 100%. The 9-month RFS at the 2x10⁹ PFU dose level was 80.4% and was not reached at the 1x10¹⁰ PFU dose level. The 12-month RFS was 71.4% at the 2x10⁹ PFU dose level and was not reached at the 1x10¹⁰ PFU dose level.

A total of 12 patients with CIS NMIBC (with or without Ta/T1) were enrolled, with 7 at the lower dose and 5 at the higher dose. At the 2x10⁹ PFU dose level, the complete response and complete response rate (CRR) was 71.4% and 100% at the 1x10¹⁰ PFU dose level across both dose levels at the 3 and 6-month CRR.

Safety and Tolerability Profile of MVR-T3011

Consistent with previous findings, MVR-T3011 demonstrated a favorable safety and tolerability profile in the study.

Most treatment-emergent adverse events (TEAEs) were grade 1 or 2. A total of 5 grade 3 TEAEs were reported. Two of these were classified as treatment-related adverse events and were consistent with reactions commonly associated with catheterization procedures. No grade 3 or above TEAEs nor dose-limiting toxicities occurred.

Mechanism of Action of MVR-T3011

MVR-T3011 is a breakthrough in HSV-1-based oncolytic immunotherapy with a proprietary 3-in-1 design.

MVR-T3011 isa replication-competent, tumor-lytic Herpes Simplex Virus 1 (HSV-1) backbone, an integrated anti-PD-(L)1 antibody, and an integrated interleukin-12 (IL-12).

The design enables the product to simultaneously lyse tumor cells while also stimulating both the innate and adaptive immune systems. It has demonstrated adaptability across multiple administration routes, including intratumoral, intracavitary, and intravenous.

MVR-T3011 is identified as the world's first HSV-1-based oncolytic immunotherapy to have completed a phase 1 trial via systemic intravenous dosing under the FDA regulatory regime.

Rationale Behind MVR-T3011 and Next Steps

The development of MVR-T3011 is situated within a market characterized by significant unmet medical needs. The current standard of care for high-risk NMIBC is BCG.

There is a significant global shortage of BCG. In the US, the available supply meets less than 30% of the total demand, creating a clear opportunity for novel therapies.

ImmVira, trial sponsor, initiated a phase 2 trial for BCG-unresponsive high-risk NMIBC in the US in June 2025. ImmVira is also progressing a global multi-regional clinical trial that will include China.

"We are highly encouraged by the interim efficacy data from the study, especially the high CR and RFS rate for both BCG-unresponsive CIS and papillary patients at 1x10¹⁰ PFU," said Grace Zhou, MD, chairwoman and CEO of ImmVira in a news release. "We have initiated a phase 2 trial for BCG-unresponsive high-risk NMIBC in the US in June 2025 and are progressing a global multi-regional clinical trial inclusive of China. We believe MVR-T3011 could emerge as the new generation of therapy for patients with high-risk, BCG-unresponsive NMIBC."

REFERENCES

1.High response in bladder cancer: Immvira announced its MVR-T3011 latest clinical results in BCG-unresponsive bladder cancer patients at 2025 Annual Meeting of the Society of Urologic Oncology. News release. ImmVira. Published and accessed December 4, 2025. https://tinyurl.com/5yxvpah2

2.A study of T3011 in patients with BCG-unresponsive NMIBC of BCG-exposed, chemotherapy-unresponsive NMIBC. ClinicalTrials.gov. Updated July 23, 2025. Accessed December 4, 2025. https://www.clinicaltrials.gov/study/NCT06971614