In April 2024 YS Biopharma announced positive interim results from an ongoing Phase III clinical trial of its next-generation PIKA Rabies Vaccine. These results suggest that the Pika Rabies Vaccine has “successfully met” the primary endpoints of the trial, with the potential to achieve best-in-class accelerated protection and meet WHO’s goal of a one-week rabies vaccine regimen to replace the conventional approach, which demands three- or four-week regimens. The vaccine uses YS Biopharma’s proprietary PIKA adjuvant technology.
PIKA technology
YS Biopharma’s PIKA technology comprises synthetic biologic complex from the team’s research, synthesised based on their proprietary GMP manufacturing technology. It can induce a “prompt production” of interferon, cytokines, chemokines, and costimulatory factors through TLr3, RIG-I, and MDA-5 signalling pathways. Administration of PIKA facilitates antigen cross-presentation by dendritic cells and “augments” CD4+ T-cell, CD8+ T-cell, and natural killer-cell responses.
The vaccine in trial
The Pika Rabies Vaccine is designed to produce a more robust immune response in a shorter time than existing rabies vaccines. It was granted orphan drug designation by the US FDA for the prevention of rabies virus infection, including post-exposure prophylaxis for rabies.
The Phase III trial is a randomised, comparator-controlled, double-blind, multicentre trial. It includes 4,500 participants from the Philippines and Pakistan. It has been designed to assess the immunogenicity, safety, and lot-to-lot consistency of three lots of the vaccine in healthy adults through a 7-day vaccine schedule.
The primary immunogenicity endpoints of the study were geometric mean titers (GMTs) of rabies virus neutralising antibodies (RVNA) and RVNA seroconversion rate at Day 14 in the first 900 participants. The secondary immunogenicity endpoints were RVNA seroconversion rate and GMTs of RVNA at Day 28, Day 42, Day 90, and Day 180 in the first 900 participants and RVNA seroconversion rate at Day 7 and Day 365 in all participants.
So far, the Pika Rabies Vaccine demonstrates non-inferior immunogenicity compared to a globally marketed comparator, as well as helping patients achieve immunity in the shorter timeframe of 7 days. The data reveal that the RVNA seroconversion rate of the vaccine was “twice that of the comparator” by Day 7.
“This accelerated and higher seroconversion rate came at no cost to safety, with the safety profile of the PIKA Rabies Vaccine remaining highly tolerable.”
Compelling evidence
Dr Zenaida Mojares, Chief Medical Officer at YS Biopharma, states that the interim results “provide compelling evidence” of the “robust immunogenicity and favourable safety profile” of the vaccine.
“By providing a shortened treatment regimen without sacrificing safety or quality, the PIKA Rabies Vaccine has the potential to improve rabies treatment and compliance. At present, the long and inconvenient regimen length for existing rabies vaccines represents a major barrier to treatment completion.”
Dr Mojares is “eager to see how the enhanced speed” might have a “positive impact on patients”.
“We are proud of our team for the hard work and dedication which got us to this point, and we are excited to see how our advances will contribute to the ongoing global fight against rabies.”
Dr David Shao is Director, President, and CEO of YS Biopharma, and expressed “sincere gratitude” to the investigators and participants of the trial.
“Thanks to their dedication and efforts, animal bite patients are expected to have access to a new rabies vaccine, thereby reducing the rate of immune failure.”
Dr Shao and team “remain committed to working closely with drug regulatory agencies” in several countries, including the Philippines, Pakistan, Singapore, and China.
“We eagerly anticipate the early approval of this innovative therapy for the benefit of patients worldwide.”
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