Providence Announces Positive Top-Line Data from Phase 2 Primary Immunization Trial of its mRNA Vaccine Candidate PTX-COVID19-B in Adults

• PTX-COVID19-B was well tolerated with no safety signals
• Non-inferior neutralizing antibody titer levels versus comparator vaccine, Comirnaty®
• Providence will initiate a Phase 3 trial of PTX-COVID19-B in a booster setting

CALGARY, Alberta, Oct. 19, 2022 (GLOBE NEWSWIRE) -- Providence Therapeutics Holdings Inc. ("Providence") today announced positive top-line data from the PRO-CL-002 Phase 2 study evaluating the safety, tolerability and immunogenicity of its mRNA COVID-19 vaccine candidate, PTX-COVID19-B. Based on the positive safety and immunogenicity results, Providence will initiate a Phase 3 trial in a booster setting.

PTX-COVID19-B demonstrated non-inferiority compared to Comirnaty®, Pfizer’s and BioNTech’s U.S. FDA-approved mRNA vaccine, with respect to the geometric mean titer (GMT) ratio of neutralizing antibodies observed two weeks after the second of two intramuscular injections. Additionally, PTX-COVID19-B was generally well-tolerated, with a safety and tolerability profile similar to Comirnaty®.

“We’re thrilled to report that, in this clinical trial, Providence’s mRNA vaccine in development for COVID-19, has performed equally to one of the most widely used COVID vaccines as demonstrated by neutralizing antibody production and safety profile,” said Brad Sorenson, chief executive officer of Providence Therapeutics. “To our knowledge, this is the first clinical trial directly comparing a candidate vaccine to an approved mRNA vaccine. We look forward to presenting more detailed results on the vaccine’s immunogenicity and safety profiles at an upcoming medical conference, as well as initiating our Phase 3 booster study.”

The PRO-CL-002 Phase 2 study recruited 565 participants aged 18 to 64 years at multiple sites in Canada and South Africa. PTX-COVID19-B was administered to 374 study participants and was generally well tolerated, with a tolerability profile similar to Comirnaty®. The overall incidence of all-cause solicited adverse events (AEs) was similar between both treatment groups after the first and second doses: 71.6% and 59.0% for PTX-COVID19-B and 74.2% and 62.4% for Comirnaty®, respectively. Solicited local AEs after the first and second doses were 62.6% and 53.8% for PTX-COVID19-B and 65.1% and 57.1% for Comirnaty®, respectively. Solicited systemic AEs after the first and second doses were 49.7% and 36.9% for PTX-COVID19-B and 58.6% and 45.3% for Comirnaty®. The percentage of PTX-COVID19-B participants who reported unsolicited AEs was also similar to Comirnaty® participants (53.7% and 52.4%, respectively). No unsolicited treatment-related serious adverse events (SAEs) were reported in either group.

The analysis of immune responses demonstrated that PTX-COVID19-B met the criteria for non-inferiority compared to Comirnaty® with respect to the GMT ratio for neutralizing antibodies at two weeks after the second dose (0.84, 95% confidence interval 0.69-1.02). The analysis two weeks after the second vaccination also demonstrated non-inferiority in terms of seroresponse rates. In an important subgroup analysis of participants with no serological evidence of previous infection or vaccination, PTX-COVID19-B immune responses two weeks after the second vaccination were also non-inferior to those induced by Comirnaty® (1.23, 95% confidence interval 0.95-1.58).

About the PRO-CL-002 Study

PRO-CL-002 (ClinicalTrials.gov identifier NCT05175742) is a Phase 2, randomized, double-dummy, observer-blind study in progress to evaluate the safety, tolerability, and immunogenicity of 40 μg PTX-COVID19-B compared to Comirnaty® in healthy SARS-CoV-2 seronegative adults aged 18 to 64 years. Subjects were randomly assigned in a 2:1 ratio to receive two doses of either PTX-COVID19-B four weeks apart (n=350) or Comirnaty® three weeks apart (n=175). The primary objective of the study is to evaluate the safety and tolerability of PTX-COVID19-B at four weeks after the second dose. Immunogenicity endpoints, measured at two weeks after the second dose, include the GMT ratio of PTX-COVID19-B compared to Comirnaty® as well as comparison of seroconversion rates of neutralizing antibodies. The study’s final analysis will comprise following all subjects 12 months after the first dose for the assessment of safety and durability of immune responses to the vaccine candidate.

About PTX-COVID19-B

PTX-COVID19-B is an mRNA vaccine candidate designed to generate potent neutralizing antibodies against the spike protein of SARS-CoV-2 and promote immunity to COVID-19. PTX-COVID19-B targets the original strain of SARS-CoV-2 and will pave the way for Providence’s future multivalent vaccines under development for current and future variants of SARS-CoV-2 and other betacoronaviruses. The safety and efficacy of PTX-COVID19-B are still under investigation, and market authorization has not yet been obtained in any market. The Providence COVID-19 vaccine program has been licensed for development and marketing rights to Everest Medicines (1952.HK) for Greater China and Southeast Asia.

About Providence Therapeutics

Providence is a Canadian clinical-stage biotechnology company pioneering mRNA therapeutics and vaccines with operations in Calgary, Alberta and Toronto, Ontario. Initially founded as a cancer vaccines company in 2015, in response to a worldwide need for a COVID-19 vaccine, Providence expanded its focus beyond oncology therapies to develop an mRNA vaccine for COVID-19. Providence works with multiple industry collaborators, universities, nongovernmental agencies and multiple arms of the Government of Canada to discover and develop vaccines and treatments for infectious diseases and cancer. This has resulted in the development of an mRNA vaccine platform that includes a proprietary design algorithm and proprietary, scalable manufacturing processes. For more information, please visit providencetherapeutics.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of applicable securities laws including regarding Providence's development plans, the initiation of phase 3 booster study, and the final analysis of the PRO-CL-002 Phase 2 study. In some cases, forward-looking statements can be identified by terminology such as "will," "may," "should," "could", "expects," "intends," "plans," "aims," "anticipates," "believes," "estimates," "predicts," "potential," "continue," or the negative of these terms or other comparable terminology, although not all forward-looking statements contain these words. The forward-looking statements in this press release are neither promises nor guarantees, and you should not place undue reliance on these forward-looking statements because they involve known and unknown risks, uncertainties, and other factors, many of which are beyond Providence's control, and which could cause actual results to differ materially from those expressed or implied by these forward-looking statements. These risks, uncertainties, and other factors include, among others: that here are a limited number of commercial products utilizing mRNA technology approved for use; the fact that mRNA technology in use by Providence is still being developed and implemented; the fact that the long term safety and efficacy of PTX-COVID19-B has not yet been established; inability to recruit patients for the conduct of the phase 3 booster study; the observation of adverse safety issues; issues regarding the manufacture and supply of PTX-COVID19-B; our capacity to meet supply and demand for our products; market acceptance of PTX-COVID19-B; the continuation of our collaborations and other significant agreements with our existing commercial partners and third-party suppliers and our ability to establish and maintain additional collaboration agreements; our expectations regarding our financial performance, including revenues, expenses, gross margins, profitability, liquidity, capital expenditures and income taxes; our estimates regarding our capital requirements; our ability to meet anticipated timelines for the development of our products; and unforeseen regulatory delays. Except as required by law, Providence disclaims any intention or responsibility for updating or revising any forward-looking statements contained in this press release in the event of new information, future developments or otherwise. These forward-looking statements are based on Providence's current expectations and speak only as of the date hereof.

Investor Contact:
Noy Wong
Providence Therapeutics
investor@providencetherapeutics.com
403-265-3765

Media Contact:
Veronica Eames
LifeSci Communications, LLC
veames@lifescicomms.com
646-970-4682