Closely on the heels of Oxford’s vaccine, CanSino Biologic’s Ad5 vector based vaccine published the phase 2 results of its vaccine in Lancet. The trial was conducted in smaller pool of 508 participants in a single centre in Wuhan, China. Two different doses of vaccine were administered to the investigational group and both doses of vaccine induced significant neutralizing antibody responses after a single administration. As compared to the Oxford ChAdOx1 vaccine, 52% of the participants in the trial had pre-existing immunity to Ad5 which significantly limited the antibody response elicited by the Ad5-vectored vaccine, however those with immunity showed higher tolerability to the vaccine as observed by the occurrence of milder fever than those in the younger population with more severe fever and other adverse events. Pre-existing anti-Ad5 immunity could be a significant bottleneck in the development and would need additional investigation and data to be overcome.
This current safety and efficacy data published by Cansino and earlier by Oxford and Moderna increases our hope to defeat the pandemic. Additionally, to address scale-up for phase 3 trials and potential supply which is the next imminent phase in vaccine development manufacturing, vaccine manufacturers, CDMOs and governments have been making collective investments for facility and capacity expansion. We’ve previously covered the slew of investments in the space with AstraZeneca already committing for a total of 2 billion doses to governments in different geographies and has forged agreements with multiple CDMOs to meet this supply commitment. The latest announcement comes from Valneva signing an agreement with the UK Government to supply 100 million doses of its inactivated whole virus vaccine which includes 60 million doses initially and an additional 40 million doses once the vaccine is proven to be safe and efficacious. Under the terms of the deal, the UK government will fund the clinical studies and an investment into the expansion of its Scotland site is under discussion. The UK government also signed a deal to procure 30 million doses on Pfizer’s and BioNTech’s jointly developed vaccine.
The pace of various COVID-19 vaccines development is commendable and it is reassuring to see the spirit of cooperation between different stakeholders while we remain optimistic that the overarching aim of equitable access to the vaccines will be upheld by all involved.