Replimune Provides Data Update from its RP1 (vusolimogene oderparepvec) and RP2 Programs and Announces Plans to Expand the Development of RP2/3 Beyond Phase 1 High rate of complete responses in RP1 skin cancer cohorts un

Replimune Provides Data Update from its RP1

(vusolimogene oderparepvec) and RP2 Programs and

Announces Plans to Expand the Development of RP2/3 Beyond Phase 1

High rate of complete responses in RP1 skin

cancer cohorts underscore the potential for profound patient benefit and supports the ongoing registration directed development programs

RP2 data confirms the signal with RP1 in anti-PD1

failed melanoma, uveal melanoma and in treating patients whose cancer has metastasized to the liver

Announces plans to initiate broad Phase 2 development

of RP2 and/or RP3 in tumor types that commonly metastasize to the liver

Virtual investor event to be held at 8:00 am

MA, June 3, 2021 - Replimune Group, Inc. (NASDAQ: REPL), a biotechnology company developing oncolytic immuno-gene therapies

derived from its Immulytic platform, today announced updated interim data from the Phase 2 skin cancer cohorts combining RP1

(vusolimogene oderparepvec) with Opdivo *

(nivolumab) and data from RP2 alone and in combination with Opdivo that continues to provide strong support for development in its lead

indications. Additionally, Replimune announced plans to initiate a Phase 2 clinical trial program in tumor types that metastasize to the

liver. A virtual investor event will be held today at 8:00 a.m. ET to discuss the updated data.

"As our data matures there are some clear themes emerging,"

said Philip Astley-Sparke CEO of Replimune. "In our longest-running clinical trial of RP1 combined with Opdivo in melanoma and in

non-melanoma skin cancers including cutaneous squamous cell carcinoma (CSCC), we are seeing a clear trend that partial responses tend

to convert to complete responses over time, providing many patients with the potential for a cure while also having a transformative long-term

impact on quality of life. Our updated data further support our two registration-directed studies in skin cancers. We look forward to

seeing if we can replicate the data we have seen with RP1 in skin cancers in anti-PD1/L1 failed non-small cell lung cancer (NSCLC), where

we recently dosed our first patient. The signal with RP1 in patients who have failed anti-PD1 is continuing with RP2 and reinforces the

potential utility of our platform for treating patients who have failed prior immune checkpoint therapy. Finally, the signal with RP1

indicating the potential to treat patients with liver metastases, who in general have a very poor prognosis, has been further confirmed

with RP2, where we are now planning to move into Phase 2 development with RP2/3 in tumor types that commonly metastasize to the liver,

including colon cancer, lung cancer and breast cancer."

Updated clinical data from the Phase 2 cohort with RP1 in combination

with Opdivo in patients with CSCC and other non-melanoma skin cancers continues to support the CERPASS registration-directed clinical

trial of RP1 in combination with Libtayo * (cemiplimab) in CSCC

The data continues to demonstrate that RP1 in combination with Opdivo

is well tolerated and that it drives deep and durable responses in patients with CSCC with the number of complete responses (CRs), a dual

independent primary endpoint in the CERPASS study, continuing to increase. At the current data cut off (n=15), seven of the nine responses

are complete responses with a current CR rate of 46% and overall response rate (ORR) of 60%. Another potentially eighth complete response

will require biopsy confirmation. The Company believes this data provides clear differentiation versus anti-PD1 therapy alone and provides

strong validation of Replimune's current registration-directed clinical development plan, with the initial readout of the CERPASS

study expected in 2022.

Updated clinical data evaluating RP1 in combination with Opdivo

in anti-PD1 failed melanoma patients continues to strongly support the Company's registration-directed cohort in the IGNYTE clinical

Sixteen anti-PD1 failed cutaneous melanoma patients were enrolled into

the previously reported 30 patient cohort in melanoma (which included anti-PD1 na ve cutaneous melanoma, mucosal and uveal melanoma,

in addition to anti-PD1 failed cutaneous melanoma). The status of the anti-PD1 failed melanoma patients is as follows:

Despite improvements in therapy, many melanoma patients treated with

anti-PD1 therapy have primary resistance or acquire resistance to immune checkpoint blockade following initial response. The clear activity

of RP1 in combination with Opdivo in anti-PD1 failed patients, including in patients with extensive visceral disease, represents a new

potential therapeutic option for these patients. Based on the initial data with RP1 in melanoma, the Company initiated a registration-directed

125-patient cohort of anti-PD1 failed melanoma which is expected to read out in 2022. The signal with RP1 in anti-PD1 failed melanoma

indicating that the Replimune series of product candidates may provide an effective therapy for these patients has also been further confirmed

with RP2 (see below), although there are no current plans to independently develop RP2 in cutaneous melanoma.

Based on the emerging data indicating that RP1 can be safely administered

to tumors in the lung and the evidence of clinical activity in patients with lung metastases from other tumor types, including in patients

with anti-PD1 failed disease, the Company has commenced dosing into a 30 patient cohort of patients with anti-PD1/L1 failed NSCLC.

Updated RP2 monotherapy data continues to show compelling durability

of response and new data in combination with Opdivo provides initial additional evidence of the clinical utility of RP2 in patients with

hard-to-treat cancers

RP2 leverages Replimune's platform to express an anti-CTLA-4

antibody, in addition to GALV-GP R- and GM-CSF expressed by RP1. After fully enrolling patients in the RP2 monotherapy cohort (n=9) in

the Phase 1 clinical trial with RP2, 27 of the target number of 30 patients have now been enrolled in the cohort evaluating RP2 in combination

with Opdivo. With limited follow up available, initial data shows:

Replimune plans to conduct clinical trials with RP2/3 in patients

with liver metastases from a range of tumor types

"Patients with liver metastases across tumor types have a poorer

prognosis than those without, and their treatment presents a considerable clinical challenge. Liver metastases across tumor types are

also associated with systemic resistance to immune checkpoint blockade," commented Professor Mark Middleton, Professor of Experimental

Cancer Medicine in the Department of Oncology, consultant Medical Oncologist at the Oxford Cancer and Haematology Centre and Head of the

Department of Oncology at the University of Oxford, who will also present the latest data with RP1 and RP2 at today's investor event.

"Treatment of patients with liver metastases with RP1 or RP2, including patients with anti-PD1/L1 failed disease, has resulted in

durable and systemic clinical benefit and offers the potential to provide a new standard of care for this large patient group."

The data from this clinical update and an overview of the rationale

and development strategy for patients with liver metastases can be found in the presentation for today's investor event, linked

Investor event and webcast information

Replimune will host a virtual investor event today, Thursday, June

3, 2021 at 8:00 a.m. ET. The webcast and slides will be accessible live under "Events & Presentations" on the Investors

page of the Company's website at www.replimune.com or by clicking here. A replay of the event will be available on Replimune's

CERPASS is Replimune's registration-directed randomized, global

Phase 2 clinical study to compare the effects of Libtayo (cemiplimab) alone versus a combination of Libtayo and Replimune's

investigational oncolytic immunotherapy RP1. The clinical trial will enroll 180 patients with locally advanced or metastatic cutaneous

squamous cell carcinoma (CSCC) who are na ve to anti-PD1 therapy. The trial will evaluate complete response (CR) rate and overall

response rate (ORR) as its two primary efficacy endpoints as assessed by independent review, as well as duration of response, progression-free

survival (PFS), and overall survival (OS) as its secondary endpoints. The study is being run under a clinical trial collaboration agreement

with Regeneron in which the costs of the trial are shared and full commercial rights retained by Replimune. Libtayo is being jointly developed

by Regeneron and Sanofi.

IGNYTE is Replimune's multi-cohort Phase 1/2 trial of RP1 plus

Opdivo (nivolumab). There are 4 tumor specific cohorts currently enrolling in this trial including a 125-patient extension cohort

of RP1 combined with Opdivo in anti-PD-1 failed cutaneous melanoma. This cohort was initiated after completing enrollment in a prior Phase

2 cohort in the same trial of approximately 30 patients with melanoma. The additional thirty patient cohorts are studying RP1 in combination

with Opdivo in non-melanoma skin cancers which includes both na ve and anti-PD-1 failed CSCC, in microsatellite instability high,

or MSI-H/dMMR tumor types and anti-PD-1 failed non-small cell lung cancer, or NSCLC. This trial is being done under a collaboration and

supply agreement with Bristol Myer Squibb.

RP1 (vusolimogene oderparepvec) is Replimune's lead Immulytic

product candidate and is based on a proprietary new strain of herpes simplex virus engineered to maximize tumor killing potency, the immunogenicity

of tumor cell death and the activation of a systemic anti-tumor immune response.

RP2 and RP3 are derivatives of RP1 that express additional proteins.

RP2 expresses an anti-CTLA-4 antibody-like molecule and RP3 additionally expresses the immune co-stimulatory pathway activating proteins

CD40L and 4-1BBL. RP2 and RP3 are intended to provide targeted and potent delivery to the sites of immune response initiation in the tumor

and draining lymph nodes, with the goal of focusing systemic immune-based efficacy on tumors and limiting off-target toxicity.

Replimune Group, Inc., headquartered in Woburn, MA, was founded

in 2015 to develop the next generation of oncolytic immune-gene therapies for the treatment of cancer. Replimune is developing

novel, proprietary therapeutics intended to improve the direct cancer-killing effects of selective virus replication and the potency

of the immune response to the tumor antigens released. Replimune's Immulytic platform is designed to maximize systemic