- Intratumoural IVX037 showed encouraging biological and clinical activity in microsatellite stable colorectal cancer (MSS-CRC), both as a monotherapy and in combination with the PD-1 inhibitor sintilimab, particularly in KRAS/BRAF-mutant tumours.
- Disease control was observed in several MSS-CRC patients with liver metastases, especially those harbouring KRAS/BRAF mutations.
- IVX037 treatment demonstrated abscopal effects, with responses in liver, pancreatic, and lung metastases, and notable reductions in serum CEA levels in some MSS-CRC patients.
- In patients with BRAF V600E-mutant MSS-CRC, IVX037 induced rapid and widespread necrosis in injected lesions.
- Promising activity was also seen in a BRCA2-mutated ovarian cancer patient, with a durable partial response (PR) and marked decline in serum CA-125 levels.
- Combination therapy with IVX037 and sintilimab has been generally well tolerated, with no Grade 3 or higher treatment related adverse events for either agent.
- These preliminary clinical results support continued development of IVX037, particularly in combination with PD-1 inhibitors for ovarian cancer and MSS-CRC, with an emphasis on KRAS/BRAF-mutant MSS-CRC in upcoming cohort expansions.
Melbourne, Australia 20 October 2025 – ImmVirX Pty Limited, a life sciences company focused on developing next-generation, receptor targeted oncolytic RNA immunotherapies to transform outcomes for patients with some of the most prevalent and challenging cancer types, is pleased to report on progress of IVX037 in its Phase 1a/b clinical study as presented at the European Society for Medical Oncology (ESMO) Congress in Berlin, Germany from 17-21 October 2025.
IVX037 is a bioselected, non-genetically modified oncolytic picornavirus that targets CD55, a complement regulatory protein frequently overexpressed in CRC and other tumour types, especially in tumours with KRAS/BRAF mutations.
IVX037 Clinical Trial Update
The poster reported on the completed Phase 1a IVX037 monotherapy trial and the ongoing Phase 1b open-label, non-randomised, multi-centre clinical trial of intratumoural (IT) IVX037 in combination with TYVYT®1 (sintilimab, a PD1-inhibitor) in patients with advanced MSS colorectal, ovarian and gastroesophageal cancer. Additionally, the first patient in a cohort of 15 hepatocellular carcinoma (liver cancer) patients has now been dosed.
All enrolled patients presented with at least one injectable tumour and received IT doses of IVX037 on Days 1, 15, 29, 43, 57, 71, and 85, at doses of up to 7.5 × 10⁸ TCID₅₀— a dosage level previously deemed safe in the Phase 1a study. Sintilimab treatment commenced on Day 8 and was administered intravenously every three weeks at a fixed dose of 200 mg.
The primary objective of the study is to evaluate the feasibility, safety, and tolerability of IT IVX037 in combination with sintilimab, including the incidence of dose-limiting toxicities (DLTs). Tumour response was assessed using iRECIST criteria, with the first evaluation conducted on Day 43.
Nineteen patients have now been enrolled in the Phase 1b portion of the study, which is currently ongoing at eight clinical sites across Australia. To date, no DLTs or Grade 3 or higher treatment-related adverse events have been reported. The combination dosing regimen has been well tolerated.
Encouraging signs of clinical activity have been observed. Disease control was achieved in six of the first nine patients with MSS-CRC harbouring either KRAS or BRAF mutations. Importantly, five of these six patients had liver metastases, typically associated with a more aggressive disease profile. Disease control was not achieved in any patients without these mutations (wild type).
Disease control was witnessed in 21 of 33 (64%) target lesions in patients with either KRAS or BRAF mutations. Wild type patients had disease control in 1 of 10 (10%) target lesions.
Evidence of an abscopal effect—tumour reduction in non-injected lesions—was also observed. One patient with extensive metastatic disease, including involvement of the liver, lungs, and pancreas, demonstrated notable reduction in untreated lesions.
Early clinical activity was also observed in the second ovarian cancer patient enrolled in the Phase 1b combination study. The patient with a BRCA2-mutation achieved a durable and ongoing partial response (PR), accompanied by a significant reduction in serum CA-125 levels.
“These early results with IVX037 are particularly compelling given the historically poor response of MSS-CRC to immunotherapy,” said Dr Jia (Jenny) Liu, medical oncology staff specialist at The Kinghorn Cancer Centre, St Vincent’s Hospital (Darlinghurst, Sydney Australia) and Principal Investigator on the study. “The ability to achieve disease control — including in liver metastases and in patients with KRAS and BRAF mutations — is an encouraging sign of IVX037’s potential. We’re also seeing promising activity in ovarian cancer, which opens the door to broader applications of this approach. It’s exciting to be part of a study exploring a new frontier in immunotherapy.”
“The MAP kinase pathway plays a pivotal role in driving the aggressiveness and treatment resistance of tumours harbouring KRAS or BRAF mutations,” said Professor Darren Shafren, Chief Scientific Officer of ImmVirX. “Our early data suggest that activation of this pathway may enhance the oncolytic potential of IVX037 by promoting viral replication, assembly, and lytic release — offering a unique therapeutic advantage. The ability of IVX037 to selectively target tumours overexpressing CD55, particularly in colorectal cancers with MAP kinase pathway alterations, positions it as a promising candidate for combination immunotherapy strategies.”
“We are highly encouraged by the early clinical signals from IVX037, particularly in patients with KRAS and BRAF-mutant MSS-CRC, a population with historically limited treatment options,” said Dr Malcolm McColl, CEO and Co-Founder of ImmVirX. “The activity we’re seeing — both at the injected site and at distant metastases — underscores the potential of our platform to transform outcomes in hard-to-treat solid tumours. These findings reinforce our commitment to advancing IVX037 in combination with PD-1 inhibitors in expanded studies and bring new hope to patients with MSS-CRC and ovarian cancer.”
About ESMO
ESMO is a premier global oncology event, bringing together clinicians, researchers, patient advocates, journalists, and healthcare industry professionals from around the world. ESMO 2025, held in Berlin from October 17-21, showcasing groundbreaking discoveries, cutting-edge treatments, and a collaborative approach to shaping the future of cancer care. The ESMO conference in 2024 welcomed nearly 33,000 attendees.
About ImmVirX
ImmVirX is developing novel oncolytic immunotherapies to create powerful new cancer therapy combinations. Our lead asset, IVX037, is in clinical studies and our second agent, IVX055, is in pre-clinical development. Our novel oncolytic immunotherapy harnesses the power of viruses to preferentially infect and kill cancer cells and induce local and systemic anti-tumour immune responses.
The proprietary bio-selection platform enables the development of RNA viruses targeting specific receptor proteins highly expressed on a range of cancer cell types, allowing them to selectively enter, replicate in, and destroy tumour cells while creating beneficial changes in the tumour micro-environment, potentially leading to the generation of specific innate and adaptive immune responses against cancer cells.
In this way, our oncolytic immunotherapies are intended to increase the effectiveness of current therapies, primarily immune checkpoint inhibitors and CAR-T cell therapies, in fighting cancers of high unmet need including colorectal, gastric, ovarian and liver cancer.
Website: https://www.immvirx.com/
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Media Contact
Dr. Malcolm McColl
Chief Executive Officer, Acting Chairman and Co-Founder
E: [email protected]
