Everest Medicines Announces Partner Providence Reports Positive Top-Line Data from Phase 2 Primary Immunization Trial for mRNA COVID-19 Vaccine Candidate in Adults

-- Levels of neutralizing antibodies generated by PTX-COVID19-B were non-inferior to Comirnaty®--

-- PTX-COVID19-B was well tolerated with no safety signals--

-- Everest is filing IND applications for phase 3 clinical trials for booster indication--

SHANGHAI,Oct. 19,2022 --Everest Medicines (HKEX 1952.HK,"Everest",or the "Company"),a biopharmaceutical company focused on developing and commercializing transformative pharmaceutical products to address critical unmet needs in Asia Pacific markets,announced today that its partner Providence Therapeutics Holdings Inc. ("Providence") reported positive top-line data from a Phase 2 study evaluating the safety,tolerability and immunogenicity of its mRNA COVID-19 vaccine candidate,PTX-COVID19-B. Everest licensed the rights to PTX-COVID19-B for Greater China,Southeast Asia and Pakistan,from Providence in 2021 as part of a broad partnership to develop mRNA products globally leveraging the technology platform.

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®.

The 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%). 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).

"We congratulate our partner on the exciting Phase 2 data. To our knowledge,this is the first clinical trial directly comparing a candidate vaccine to an approved mRNA vaccine. We aim to initiate Phase 3 trials quickly and launch our COVID-19 vaccines in our territories," said Rogers Yongqing Luo,Chief Executive Officer of Everest Medicines. "Since completion of the transaction with Providence,we have made significant progress including in completing clinical-scale technology transfer and building commercial-scale local manufacturing capabilities in Jiashan,Zhejiang Province. We look forward to utilizing this cutting-edge and clinically validated mRNA platform as a long-term growth driver for Everest Medicines."

Everest is submitting Investigational New Drug (IND) applications for jointly-conducted phase 3 clinical trials to evaluate PTX-COVID19-B for booster indications. The company plans to file INDs for its Omicron-containing bivalent booster candidate,EVER-COVID19-M1.2,in the second half of 2022 in China and other Everest territories.

About Phase 2 Study PRO-CL-002

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 geometric mean titer (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 future multivalent vaccines under development for current and future variants of SARS-CoV-2 and other betacoronaviruses.

In September 2021,Everest entered into a strategic partnership with Providence Therapeutics Holdings Inc. ("Providence") to advance mRNA vaccines and therapies. Under the terms of the agreement,Everest owns the rights to Providence's mRNA vaccine candidates in Greater China,Brunei,Cambodia,Indonesia,Laos,Malaysia,Myanmar,Pakistan,Philippines,Singapore,Thailand,Timor-Leste and Vietnam. Everest and Providence also entered into a global collaboration under which Everest is enabled to create and develop products using the mRNA platform for product discovery across a broad range of other prophylactic and therapeutic areas with full technology transfer.

About Everest Medicines

Everest Medicines is a biopharmaceutical company focused on developing and commercializing transformative pharmaceutical products that address critical unmet medical needs for patients in Asian markets. The management team of Everest Medicines has deep expertise and an extensive track record from both leading global pharmaceutical companies and local Chinese pharmaceutical companies in high-quality clinical development,regulatory affairs,CMC,business development and operations. Everest Medicines has built a portfolio of potentially global first-in-class or best-in-class molecules,many of which are in late-stage clinical development. The Company's therapeutic areas of interest include cardio-renal diseases,autoimmune disorders,and infectious diseases. For more information,please visit its website atwww.everestmedicines.com.

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