YS Biopharma Announces Completion of Subject Enrollment in Pivotal Phase 3 Clinical Trial of PIKA Rabies Vaccine

GAITHERSBURG,Md.,Oct. 31,2023 -- YS Biopharma Co.,Ltd. (NASDAQ: YS) ("YS Biopharma" or the "Company"),a global biopharmaceutical company dedicated to discovering,developing,manufacturing,and delivering new generations of vaccines and therapeutic biologics for infectious diseases and cancer,today announced the completion of subject enrollment in its Phase 3 clinical trial (the "Phase 3 Trial" or the "Trial") of the Company's PIKA Rabies Vaccine. The Trial,which will assess the safety,immunogenicity,and lot-to-lot consistency of the PIKA Rabies Vaccine,includes 4,500 subjects.

Rabies has an almost 100% fatality rate upon emergence of clinical symptoms. Each year,it claims the lives of approximately 59,000 individuals in more than 150 countries. Transmission through bites from infected dogs accounts for over 95% of rabies-related fatalities,and 40% of these deaths occur in children under the age of 15. Although rabies is typically lethal without treatment,the administration of post-exposure prophylaxis can effectively prevent fatalities when initiated following possible exposure.

The PIKA Rabies Vaccine,which utilizes YS Biopharma's proprietary PIKA adjuvant technology,is designed to produce a more robust immune response in an accelerated timespan compared to existing rabies vaccines. Previous Phase 1 and Phase 2 clinical trials of the PIKA Rabies Vaccine have demonstrated its safety and strong immunogenicity,with the PIKA Rabies Vaccine eliciting a detectable immune response in as quick as seven days. Given these results,the PIKA Rabies Vaccine has the potential to achieve best-in-class accelerated protection and meet the WHO's goal of a one-week rabies vaccine regimen to replace the conventional three- or four-week regimens.

Dr. Muhammad Ahmad,the Principal Investigator at Central Park Teaching Hospital in Lahore,Pakistan,where the first and last subjects have been enrolled,commented,"We are excited that the enrollment of all 4,500 subjects for the PIKA Rabies Vaccine's Phase 3 Trial is now complete. The Phase 3 Trial is a critical milestone in establishing the safety and efficacy of the PIKA Rabies Vaccine. The study will provide us with more pivotal data through which we can assess the vaccine's performance on a larger scale. We hold high hopes that these findings will help establish a new standard in rabies prevention around the world,and we are proud to be taking this significant step into promising new territory."

Dr. Ralph Villalobos,the Principal Investigator at Philippine General Hospital in Manila,Philippines,where the first subject in the Philippines was enrolled,"On behalf of the other principal investigators in the Philippines,we are delighted to have completed the enrollment of this Phase 3 Trial ahead of the targeted timeline. This study will be conducted with the highest standards of safety and quality,and we are eager to proceed and generate data on the PIKA Rabies Vaccine. We are optimistic that the PIKA Rabies Vaccine will provide rapid and strong immunogenic protection against rabies,and are excited at the prospect of improving patient adherence and the chances of survivability among those exposed to rabies."

The Phase 3 Trial is a randomized,comparator-controlled,double-blind,multi-country and multi-center study that is currently being conducted in Pakistan and the Philippines. Its primary goal is to assess the lot-to-lot consistency,and safety of the PIKA Rabies Vaccine,while also seeking to demonstrate the immunologic non-inferiority and superiority of the PIKA Rabies Vaccine compared to a control vaccine. During the Trial,the PIKA Rabies Vaccine will be administered to healthy adults using a post-exposure prophylaxis schedule. Immunogenicity and consistency will be assessed using measurements of rabies virus neutralizing antibodies ("RVNA") at day 14,while immunologic non-inferiority will be evaluated based on differences in RVNA seroconversion rates between the control vaccine and the PIKA Rabies Vaccine at day 14.

Dr. Zenaida Mojares,Chief Medical Officer of YS Biopharma,"Completing subject enrollment for the Phase 3 Trial is a major advance in our PIKA Rabies Vaccine's clinical development trajectory. We achieved positive results in the Phase 1 and Phase 2 trials conducted in China and Singapore,respectively,and we are optimistic that this Phase 3 study will reinforce and build on our existing findings. As we draw closer to delivering evidence for the lot-to-lot consistency,I would like to thank the Trial subjects,principal investigators,and all our collaborating partners from around the globe for participating in this pivotal program. We remain dedicated to leveraging our advanced PIKA adjuvant technology to enhance global health and well-being,and are thrilled to explore the near-term and long-term possibilities it offers."

About YS Biopharma

YSBiopharmais a global biopharmaceutical company dedicated to discovering,and delivering new generations of vaccines and therapeutic biologics for infectious diseases and cancer. It has developed a proprietary PIKA®immunomodulating technology platform and a new generation of preventive and therapeutic biologics targeting Rabies,Coronavirus,Hepatitis B,Influenza,Shingles,and other virus infections. YSBiopharmaoperates inChina,the United States,Singapore,andthe Philippines,and is led by a management team that combines rich local expertise and global experience in the biopharmaceutical industry. For more information,please visitinvestor.ysbiopharm.com.

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