Dr. Matt Coffey reports

ONCOLYTICS BIOTECH(TM) ANNOUNCES UPDATED RANDOMIZED PHASE 2 DATA FROM BRACELET-1 METASTATIC BREAST CANCER TRIAL THAT SHOW PELAREOREP DRIVING ROBUST INCREASES IN PROGRESSION-FREE SURVIVAL AND CONFIRMED OVERALL RESPONSE RATE

Oncolytics Biotech Inc. has released updated results from Bracelet-1, a randomized phase 2 trial in HR+/HER2- metastatic breast cancer, which include data featured in an oral presentation at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, as well as additional new data and analyses.

Bracelet-1 enrolled 48 patients, including 45 that were randomized and well balanced across three cohorts evaluating: (1) paclitaxel monotherapy; (2) paclitaxel in combination with pelareorep; and (3) paclitaxel plus pelareorep in combination with the anti-PD-L1 checkpoint inhibitor, avelumab (Bavencio). A three-patient safety run-in was also conducted with patients receiving pelareorep, paclitaxel and avelumab prior to randomization. All participants enrolled in the trial had previously progressed on at least one hormone-based therapy with a CDK 4/6 inhibitor. No patients in Bracelet-1 received chemotherapy for metastatic disease prior to enrolling in the trial.

Updated data from Bracelet-1 showed a median progression-free survival (mPFS) of 9.5 months in the paclitaxel plus pelareorep cohort versus 6.3 months in the paclitaxel monotherapy cohort for a hazard ratio of 0.29 as of a March 3, 2023, cut-off date. Confirmed overall response rate (ORR) in these cohorts was 37.5 per cent and 13.3 per cent, respectively. As previously reported, ORR at week 16 (the trial's primary end point) in the pelareorep plus paclitaxel and paclitaxel monotherapy cohorts was 31.3 per cent and 20 per cent, respectively. Overall survival data from the trial continue to mature.

"Bracelet-1's positive results complement prior phase 2 data showing a statistically significant increase in overall survival when pelareorep was combined with paclitaxel by demonstrating similar robust improvements in PFS and ORR in less heavily pretreated patients," said Dr. Matt Coffey, president and chief executive officer. "Given this exciting finding, our next step is to discuss our data with the FDA to investigate incorporating dual PFS and OS end points into our breast cancer program's registrational study. Including a PFS end point could substantially reduce the time to a pivotal readout from the registrational trial, thereby accelerating pelareorep's path to potential approval as we work to address the urgent needs of HR+/HER2- breast cancer patients."

A summary of response and PFS data from all 48 patients enrolled in Bracelet-1 is shown herein.

Key biomarker and safety findings from Bracelet-1 include:

• Association between T cell expansion and efficacy measures: A statistically significant increase in T cell fraction, a measure of T cell expansion, was observed in cohort 2 (paclitaxel plus pelareorep) but not cohort 3 (paclitaxel plus pelareorep plus avelumab);
• Generally favourable and manageable safety profile: Pelareorep displayed a manageable safety profile consistent with what has been observed in prior clinical trials that have collectively treated over 1,100 patients.

Dr. Thomas Heineman, chief medical officer, commented: "Bracelet-1's impressive initial results are maturing quite favourably. While five patients in the pelareorep-paclitaxel group had partial responses at week 16, six patients in total had confirmed responses. This includes two patients who improved from stable disease to partial responses at later times, consistent with pelareorep's immunologic mechanism of action. Moreover, the compelling ORR and PFS hazard ratio achieved align with translational results showcasing pelareorep's immune-mediated mechanism of action and complement additional data that support the combination therapy's generally favourable safety profile. Collectively, these results bolster an expansive clinical data set supporting the potential of pelareorep-paclitaxel combination therapy in HR+/HER2- metastatic breast cancer and are expected to propel our program to a pivotal licensure-enabling study."

A copy of slides from the ASCO oral presentation on Bracelet-1, titled "Bracelet-1 (PrE0113): Inducing an Inflammatory Phenotype in Metastatic HR+/HER2- Breast Cancer with the Oncolytic Reovirus Pelareorep in Combination with Paclitaxel and Avelumab," is available on the posters and publications page of Oncolytics' website. Additional data and analyses from Bracelet-1 beyond those reported at the ASCO annual meeting will be available in the most recent investor presentation. Details of the key opinion leader webinar are shown below.

Key opinion leader webinar

Oncolytics will host a key opinion leader (KOL) webinar featuring Richard Vile, PhD (Mayo Clinic), Aleix Prat, MD, PhD (Clinic Barcelona), and Martine J. Piccart, MD, PhD (Universite Libre de Bruxelles) today, June 5, 2023, at 8 a.m. ET. During the webinar, the KOLs and members of the Oncolytics management will discuss the current treatment landscape for HR+/HER2- metastatic breast cancer, as well as Bracelet-1's results. A live question-and-answer session will follow a formal presentation and roundtable discussion with the KOLs. To register for the event, please click here.

About Bracelet-1

The Bracelet-1 (breast cancer with the oncolytic reovirus pelareorep in combination with anti-pd-l1 and paclitaxel) study is an open-label, phase 2, randomized study in patients with HR+/HER2-, endocrine-refractory metastatic breast cancer. The study randomized 45 patients 1:1:1 into three cohorts. A three-patient safety run-in was also conducted with patients receiving pelareorep, paclitaxel and avelumab prior to randomization. The three cohorts are treated as follows:

• Cohort 1: paclitaxel;
• Cohort 2: paclitaxel plus pelareorep;
• Cohort 3: paclitaxel plus pelareorep plus avelumab (Bavencio).

Patients in cohort 1 receive paclitaxel on days 1, 8 and 15 of a 28-day cycle. Patients in cohort 2 receive the same paclitaxel regimen as cohort 1, plus pelareorep on days 1, 2, 8, 9, 15 and 16 of the 28-day cycle. Patients in cohort 3 receive the same combination and dosing regimen as cohort 2, plus avelumab on days 3 and 17 of the 28-day cycle. The primary end point of the study is overall response rate at week 16. Exploratory end points include progression-free survival, peripheral and tumour T cell clonality, inflammatory markers, and safety and tolerability assessments.

About Oncolytics Biotech Inc.

Oncolytics is a biotechnology company developing pelareorep, an intravenously delivered immunotherapeutic agent. This compound induces anti-cancer immune responses and promotes an inflamed tumour phenotype -- turning cold tumours hot -- through innate and adaptive immune responses to treat a variety of cancers.

Pelareorep has demonstrated synergies with multiple approved oncology treatments. Oncolytics is currently conducting and planning combination clinical trials with pelareorep in solid and hematological malignancies as it advances toward registrational studies in metastatic breast cancer and pancreatic cancer.

We seek Safe Harbor.