On May 27, 2026 ViroMissile, Inc., a cancer immunotherapy company pioneering the IDOV (Intravenously Deliverable Oncolytic Virus) platform, reported the presentation of clinical data from an investigator-initiated Phase I study of IDOV-Safe, the company’s first clinical-stage oncolytic virus, at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting in Chicago, Illinois.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

The poster, titled "Intravenous oncolytic virus IDOV-Safe in pMMR/MSS metastatic colorectal cancer" (Abstract #3536), will be presented on Saturday, May 30th, at Poster Board 290 by Tong Xie, MD, of Peking University Cancer Hospital & Institute in Beijing, China. The study’s principal investigator is Lin Shen, MD, of the same institution.

"These findings validate a core hypothesis underlying our IDOV platform that systemic delivery of an oncolytic virus can prime immune responses even in tumors historically considered immune-cold," said Nanhai George Chen, PhD, Founder and Chief Executive Officer of ViroMissile. "Achieving a 30-46% response rate in pMMR/MSS metastatic colorectal cancer, a setting where checkpoint inhibitors have largely fallen short, represents an encouraging signal that warrants further investigation. We look forward to advancing this approach into our contemplated registrational Phase 2 study."

The data are from a study evaluating IDOV-Safe in combination with fruquintinib, a VEGF inhibitor, and toripalimab, a PD-1 inhibitor, in patients (n=55) with proficient mismatch repair/microsatellite stable (pMMR/MSS) metastatic colorectal cancer (mCRC). Patients with mCRC historically have limited treatment options and poor response to checkpoint inhibitor-based immunotherapy. The poster highlights results from a key expansion cohort (n=20) where treatment with IDOV-Safe demonstrated an objective response rate (ORR) of 30.0% and a disease control rate (DCR) of 70.0%, with a median progression-free survival (PFS) of 8.7 months. In patients without liver metastases, ORR reached 46.2% and median PFS extended to 10.8 months.

Study Design

The investigator-initiated Phase I trial treated a total 55 patients with pMMR/MSS mCRC across all cohorts. The study employed a triplet 3+3 dose-escalation design to assess dose-limiting toxicities (DLTs) and determine the maximum tolerated dose and the recommended expansion dose. Expansion cohorts assessed IDOV-Safe in combination with fruquintinib and with or without toripalimab across three combination strategies: sequential, early, and IO-free. Primary and secondary endpoints included safety, objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS).

Key findings

Safety
IDOV-Safe demonstrated a manageable safety profile across all dose levels
62% of patients experienced Grade 3 or higher treatment-related adverse events (TRAEs), with only one Grade 4 TRAE reported as a dose-limiting toxicity (DLT). The most common TRAEs were transient fever, thrombocytopenia, and neutropenia
No treatment-related deaths were observed
Efficacy/Tumor Response
In the sequential combination expansion cohort, which received IDOV-Safe at the higher dose level in combination with fruquintinib and toripalimab, the results demonstrated:
An objective response rate (ORR) of 30.0% was observed overall in the key expansion cohort
In patients without liver metastases, ORR reached 46.2% with a DCR of 84.7% and a median PFS of 10.8 months, compared to a median PFS of 3.7 months in patients with liver metastases
Median progression-free survival (PFS) was 8.7 months overall.
The poster will be available on the ViroMissile website after the conclusion of the session.

(Press release, ViroMissile, MAY 27, 2026, View Source [SID1234666104])