(April 14, 2023, Kunming) Walvax Biotechnology Co., Ltd. ("Walvax", 300142.SZ) announced the publication of safety and preliminary immunogenicity results from the Phase 1 clinical trial of Walrinvax™, a prophylactic pichia pastoris-expressed bivalent (types 16 and 18) HPV vaccine developed by Shanghai Zerun Biotechnology Co., Ltd. (ZerunBio), a subsidiary of Walvax. Upon that Walrinvax™ was demonstrated to be safe and highly immunogenic in nonclinical studies, with approval for human clinical studies from NMPA (National Medical Products Administration, previously referred to as CFDA) in 2011, the Phase 1 clinical study was initiated in 2012 to primarily evaluate the safety and tolerance of Walrinvax™ at different doses in different age groups (18-45 years & 9-17 years), as well as the neutralizing antibody responses against HPV types 16/18 as the secondary endpoint. The results were published in Vaccine on April 13, 2023 (See full text at https://doi.org/10.1016/j.vaccine.2023.04.009). Key findings of the phase 1 clinical study are as below:

Outstanding safety

• Both high-dose and low-dose investigational vaccines were well-tolerated in all age groups.
• Incidence rates of any systemic reactions in the high-dose group, low-dose group and placebo group were 27.5%, 30.0%, and 16.3%, respectively. The most common symptoms of systemic adverse reactions were fever and headache, followed by fatigue and diarrhea.
• Incidence rates of any local reactions in the high-dose group, low-dose group and placebo group was 40.0%, 35.0%, and 17.5%, respectively. Pain at the injection site was the most frequently reported symptom of local adverse reactions, followed by itching and swelling.
• Systemic and local reactions were mainly mild to moderate in severity, the majority of which occurred within 7 days and resolved without further attention.
• No vaccine-related SAEs or deaths resulted from SAEs were noted.

Potent neutralizing antibody responses

• Types 16/18 antigens included in HPV-2 were immunogenic at each dose and the immune response was further boosted at Doses 2 & 3.
• Seropositivity rates of neutralizing antibodies against HPV types 16 and 18 were both 100% after full-course vaccination for high-dose and low-dose groups.
• Neutralizing antibodies at relatively high levels were induced by both doses at Month 7 (one month after the 3rd dose), with maximum titers against HPV types 16 and 18 being 81,920 and 40,960, respectively. The GMT levels of neutralizing antibodies against HPV types 16 and 18 were similar between different dose groups with no significant differences after 3 doses.

About the Phase 1 Clinical Study (311-HPV-1001)

The Phase 1 clinical study 311-HPV-1001, registered on clinicaltrials.gov (NCT01548118), was a randomized, double-blind, placebo-controlled study with 160 healthy females aged 9–45 years enrolled in Guangxi, China, who were randomized (1:1:2) to receive either low (0.5 mL) or high (1.0 mL) doses of Walrinvax™, or placebo (aluminum adjuvant) in a 0, 2, 6 months schedule. Subjects were stratified by age (18-45 years & 9-17 years) to adopt a stepwise vaccination procedure. Younger subjects were only to be vaccinated if satisfactory safety results were obtained in the older age group at 7 days post Dose 1. Meanwhile, a similar step-wise strategy was also implemented regarding the low- and high-dose groups. Subjects included in the high-dose group of a specific age strata were only to be vaccinated if satisfactory safety results were obtained in the low-dose group at 7 days post Dose 1. Participants were observed for at least 30 minutes for immediate adverse reactions following each dose. Solicited local and systemic adverse reactions (ARs) within 7 days post each vaccination were monitored using diary cards. Unsolicited adverse events (AEs) within 30 days following each vaccination and SAEs throughout the study were also collected. Blood samples were collected at Day 0 before vaccination and at Day 4 post each vaccination for hematology assessment. Serum samples for immunogenicity assessment were obtained at baseline (Day 0), and Days 60, 180 and 210 to measure anti-HPV neutralizing antibody using a pseudovirion-based neutralizing assay (PBNA).

About Walrinvax™ (Recombinant Human Papillomavirus Bivalent [Types 16, 18] Vaccine [Pichia pastoris])

Walrinvax™ is a non-infectious recombinant bivalent vaccine prepared from the purified virus-like particles (VLPs) of the major capsid (L1) protein of Human Papillomavirus (HPV) Types 16 and 18, developed by Shanghai Zerun Biotechnology Co., Ltd. (ZerunBio), one subsidiary of Walvax Biotechnology Co., Ltd. Walrinvax™ is presented as a single-dose of 0.5mL in a vial or pre-filled syringe (PFS) for intramuscular injection only, with 40 μg Human Papillomavirus Type 16 L1 protein and 20 μg Human Papillomavirus Type 18 L1 protein as active ingredients. Walrinvax™ is to be administered as a 2-dose schedule at 0, 6 months (for females 9-14 years of age only) or 3-dose schedule at 0, 2, and 6 months (for females 9-30 years of age). Walrinvax™ can be stored and transported at 2℃ to 8℃ with protection from light. The shelf life of the vaccine is 24 months.

About ZerunBio

Shanghai Zerun Biotechnology Co., Ltd. (ZerunBio) is an innovative biopharmaceutical company focusing on the research, development and manufacturing of new recombinant human vaccines. The company was founded in 2003 and is located in Zhanjiang Hi-Tech Park, Pudong New District, Shanghai. ZerunBio is a subsidiary of Walvax Biotechnology Co., Ltd.

About Walvax

Founded in 2001, Walvax Biotechnology Co., Ltd. (Walvax) is a leading vaccine producer, engaged in research and development, manufacturing and distribution of safe and efficacious quality vaccines. Headquartered in China’s southwestern city Kunming in Yunnan Province, Walvax went to IPO in 2010 (300142.SZ) and started business expansion from traditional vaccines to innovative vaccines. With the vision of dedicating to be the pride domestically and the pioneer globally in the vaccine industry, producing efficacious, quality, innovative and affordable products to protect people from the world’s deadliest diseases, Walvaxs purpose is to help everyone live a healthy life. For further information please visit https://en.walvax.com/about-us/our-company and follow us on Twitter at @WalvaxBiotech and LinkedIn.