Developing a new generation of cancer treatments called oncolytic immunotherapies.

At Replimune, we are committed to developing a new generation of cancer treatments called oncolytic immunotherapy. Oncolytic immunotherapy uses viruses that have been modified to selectively replicate in and kill tumors. These investigational medicines are designed to fight cancer in two ways:

  1. Directly kill tumors into which they are injected
  2. Activate the immune system to kill cancer cells anywhere in the body

Replimune is working to advance the science of oncolytic immunotherapy to improve on existing therapies and help treat more patients with a variety of tumor types. Our goal is to develop powerful therapies which move beyond incremental improvements to truly overcome cancer.

About our Investigational Medicines

RP1 is Replimune’s first investigational cancer therapy being studied in clinical trials. RP1 is a version of herpes simplex virus type 1, the virus that generally causes cold sores or fever bilsters, which has been engineered to replicate selectively in tumors. To aid in the direct killing of tumors and in the induction of anti-tumor immune response, RP1 is ‘armed’ with two genes, a gene encoding a fusogenic protein intended to result in enhanced cell death and enhanced immunogenicity of cell death, and a gene encoding GM-CSF, a cytokine intended to aid immune activation.

About Replimune’s Clinical Trials

Our clinical program is designed to evaluate the safety and efficacy of our investigational medicines in a range of solid tumors as single agents and in combination with other therapies.

Prior research has shown that oncolytic immunotherapy may be able to increase the effectiveness of some other cancer therapies that activate the immune system to fight cancer.

We conduct our clinical trials to the highest possible standards and in accordance with our ethical, legal and regulatory obligations. The safety of patients is always our priority.

To learn more about our currently ongoing phase 1/2 clinical trial of RP1 in combination with nivolumab anti-PD-1 therapy in patients with melanoma, bladder cancer, non-melanoma skin cancers and MSI-H cancers, including inclusion/exclusion criteria and clinical trial sites, please visit the listing on

Find a Clinical Trial Site

Learn About Administration of Oncolytic Immunotherapy

Administering an Oncolytic Immunotherapy to Patients with Superficial / Cutaneous / Nodal Tumors from Replimune on Vimeo.

Administering an Oncolytic Immunotherapy to a Deep Visceral Organ from Replimune on Vimeo.