The US pharma giant Pfizer Inc and BioNTech SE have sought permission from the US Food and Drug Administration to expand the enrolment of their Phase 3 COVID-19 vaccine trial to 44,000. Pfizer said in a statement that enrolment in the trial has been proceeding as planned and the company expects to reach its initial target of up to 30,000 participants next week.
"The proposed expansion would allow the companies to further increase trial population diversity, and include adolescents as young as 16 years of age and people with chronic, stable HIV (human immunodeficiency viruses), Hepatitis C, or Hepatitis B infection, as well as provide additional safety and efficacy data," Pfizer said.
The trial is event-based and there are many variables that will ultimately impact read-out timing, Pfizer said.
Pfizer said if trials are successful, the companies would submit the vaccines for approval as early as October. "As stated previously, based on current infection rates, the companies continue to expect that a conclusive readout on efficacy is likely by the end of October," it added.
Pfizer and its German partner BioNTech last month said they would take their COVID-19 vaccine candidate with the fewest side effects into final-stage testing, as reported by Associated Press. The companies also compared data from early-stage testing of two vaccine candidates. The initial results showed both of them improved immune systems and did not cause side effects.
Apart from Pfizer and BioNtech, there are multiple COVID-19 vaccine candidates that have made significant headway and are aiming to deliver their vaccine in the market as soon as this year. Prominent among those are Oxford-AstraZeneca, Bharat Biotech's COVAXIN, China's Sinovac, Moderna, Novavax and China's CanSino.
The Oxford University-AstraZeneca coronavirus vaccine last week halted trials after a participant reported an unexplained illness. However, AstraZeneca on Saturday announced it has resumed the phase 3 trials after getting a nod from the Medicines Health Regulatory Authority (MHRA) in the UK.
"Clinical trials for the AstraZeneca Oxford coronavirus vaccine, AZD1222, have resumed in the UK following confirmation by the Medicines Health Regulatory Authority (MHRA) that it was safe to do so," the company said in a statement.
In India, Adar Poonawalla-led Serum Institute of India , which is also the official partner of the Oxford University-AstraZeneca vaccine, had also halted its trials after the Drugs Controller General of India raised objections.
However, the world's biggest vaccine maker will now have to seek clearance from the Data and Safety Monitoring Board (DSMB) in the UK and DSMB India before resuming trials and recruiting new participants for conducting COVID-19 trials in India.