GSK and Medicago Announce Positive Phase 3 Results for Plant-Derived Adjuvanted COVID-19 Vaccine Candidate

Shanghai, December 8, 2021 /PRNewswire/ -- GSK and Medicago Inc., a biopharmaceutical company headquartered in Quebec City, recently announced positive results for efficacy and safety in a global Phase 3 placebo-controlled efficacy study of a plant-derived COVID-19 candidate vaccine adjuvanted with GSK's pandemic adjuvant. The study was conducted in more than 24,000 participants (adults aged 18 and above) across six countries.

The vaccine efficacy was demonstrated in an environment dominated by SARS-CoV-2 variants, which is different from most of the published Phase 3 trials. Most of the currently licensed COVID-19 vaccine Phase 3 efficacy trials were conducted when only the original virus was circulating and are not directly comparable. The overall vaccine efficacy against all SARS-CoV-2 variants was 71% (95% CI: 58.7, 80.0; Per-Protocol Analysis: PP). In the population without prior COVID-19 exposure and initially seronegative, the corresponding efficacy was 75.6% (95% CI: 64.2-83.7; PP). The efficacy of this candidate vaccine against all severities of COVID-19 caused by the globally dominant Delta variant was 75.3% (95% CI: 52.8, 87.9; PP). The efficacy against the Gamma variant was 88.6% (95% CI: 74.6, 95.6; PP). Although there were a small number of severe cases during this study, none occurred in the vaccinated group. No cases of the Alpha, Lambda, or Mu variants were observed in the vaccinated group, while 12 cases were observed in the placebo group. During the study period, the Omicron (Omicron) variant had not yet become widespread.

During the study period, no related serious adverse events were reported; reactogenicity was generally mild to moderate and transient, with symptoms lasting an average of one to three days. To date, the Phase 3 study results have confirmed a safety profile consistent with the Phase 2 study findings. Even after the second dose, the incidence of mild fever was low (<10%). The full results of the Phase 3 study will be published in a peer-reviewed journal as soon as possible.

Based on these results, Medicago will immediately seek registration approval from Health Canada as part of its rolling submission. This candidate vaccine has not yet been approved by any regulatory authority.

"For Medicago and the new vaccine platform, this is an incredible moment. Our clinical trial results demonstrate the power of plant-derived vaccine manufacturing technology. If approved, it will become the world's first plant-derived vaccine for human use and contribute to the global fight against the COVID-19 pandemic."”MedicagoCEO and President of the CompanyTakashi NagaoIndicates,"I want to thank everyone who participated in our clinical trials, the collaborators at the clinical trial sites, GSK’s partners, the Canadian government and the Quebec government, all employees of the company, and Mitsubishi Tanabe Pharma for their contributions to advancing vaccine science at a time when the world needs it."”

GSKGlobal Head of Adjuvanted COVID-19 Vaccines and Chief Medical OfficerThomas BreuerIndicates:"The data were obtained in an environment without the circulation of the original strain, and these results are encouraging. The global COVID-19 pandemic continues to exhibit new characteristics, with the Delta variant currently dominant and the Omicron variant beginning to emerge; other variants may also follow. The combination of GSK's existing pandemic adjuvant and Medicago's plant-based vaccine technology holds great promise as an effective vaccine option that remains stable under refrigerated conditions, helping people combat SARS-CoV-2."

Over the past 20 years, Medicago has been committed to developing plant-based technologies and using this unique technology to produce virus-like particles (VLPs) for its protein-based vaccines. The design of VLPs mimics the original structure of viruses, making them easily recognizable by the immune system. Since VLPs lack core genetic material, they are non-infectious and unable to replicate. VLP vaccines developed through other technologies have been used worldwide for over 30 years.

“I am delighted to see that our candidate vaccine can continue to advance and bring the world’s first plant-derived vaccine against COVID-19, enhancing the diversity of available vaccines, helping to improve public health, and protecting more people.”Yosuke Kimura, Chief Scientific Officer of Medicago Inc., said.

Medicago Initiates Registration Process for Plant-Derived Adjuvant COVID-19 Candidate Vaccine with U.S. FDA and UK MHRA; Currently in Preliminary Discussions with WHO for Submission Preparation. Medicago has also launched a Phase 1/2 trial in Japan and plans to submit for regulatory approval in spring next year, combining results from global Phase 2/3 studies.

About2/3Phase Research

This Phase 2/3 study utilized a multi-part design aimed at confirming the selected candidate vaccine formulation and vaccination schedule (two doses of 3.75MicrogramThe antigen, combined with GSK's pandemic adjuvant and administered 21 days apart, demonstrated favorable vaccine characteristics in healthy adults aged 18-64, elderly subjects aged 65 and above, and adults with comorbidities.

Phase 2 trial was a randomized, observer-blinded, placebo-controlled study designed to evaluate the safety and immunogenicity of an adjuvanted recombinant COVID-19 plant-derived candidate vaccine in subjects aged 18 years and above. The study was conducted across multiple research centers in Canada and the United States, including healthy adults (18-64 years), elderly individuals (over 65 years), and adults with comorbidities. Each age group enrolled up to 306 participants who were randomly assigned at a ratio of 5:1 to receive either the adjuvanted candidate vaccine or placebo; elderly participants (65-74 years and ≥75 years) were stratified at a ratio of 2:1. All participants were followed up for 12 months after the final vaccine dose to assess safety and the durability of the immune response for the final analysis.

The Phase 3 trial was initiated in March 2021, using an event-driven, randomized, observer-blinded, crossover placebo-controlled design to evaluate the efficacy and safety of the candidate vaccine formulation compared to placebo in more than 24,000 participants across Canada, the United States, the United Kingdom, Mexico, Argentina, and Brazil.

The published data are based on the per-protocol population, including only data from participants who adhered to the protocol throughout the study. A parallel intention-to-treat (ITT) analysis, which considered all participants as treated regardless of protocol adherence, yielded very similar results.

The vaccination procedure requires two intramuscular doses (3.75MicrogramAntigen, combined with GSK pandemic adjuvant), administered 21 days apart. Vaccine stored at 2Degrees CelsiusTo 8Degrees Celsius, which can be distributed through traditional vaccine supply and cold chain channels.