Bharat Biotech, which had sought Drugs Controller General of India's (DCGI) nod for conducting phase 3 clinical trials of its COVID-19 vaccine candidate, has been asked to submit complete safety and immunogenicity data of the ongoing phase 2 trial, besides providing some clarifications, before proceeding for the next stage.
The vaccine candidate -- 'Covaxin' -- is being indigenously developed by the Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR).
According to officials, the Hyderabad-based vaccine maker applied to the DCGI on October 2, seeking its permission to conduct phase 3 randomised double-blind placebo-controlled multicentre trial of its COVID-19 vaccine candidate.
The firm in its application said that the study would cover 28,500 subjects aged 18 years and above and would be conducted in 19 sites -- including Delhi, Mumbai, Patna and Lucknow -- across 10 states.
According to sources, the phase 2 trial of the Covaxin is going on and the second dose is yet to be given to volunteers at some sites.
"The company presented phase-3 clinical trial protocol along with interim data of phase 1 and 2 clinical trials," an official said.
The subject expert committee (SEC) at the Central Drugs Standard Control Organisation (CDSCO) deliberated on the application on October 5.
'After a detailed deliberation, the committee opined that the design of the phase-3 study is in principle satisfactory except for clarification on definition of asymptomatic, etc.
'However, the study should be initiated with appropriate dose identified from the phase 2 safety and immunogenicity data. Accordingly, the firm should submit safety and immunogenicity data from phase 2 trial for consideration,' the panel said in its recommendations.
The SEC during its discussion also observed that the vaccine was well-tolerated in all dose groups and no serious adverse events have been reported so far, a source said.
The most common adverse event was pain at the injection site, which resolved transiently, the source said.
The phase-3 clinical trial application proposed a dose of 0.5 ml on day 0 and 28, sources said.
Besides, Bharat Biotech, indigenously developed vaccine candidate by Zydus Cadila Ltd is in the phase 2 of the human clinical trials.
The Pune-based Serum Institute of India, which has partnered with AstraZeneca for manufacturing the Oxford COVID-19 vaccine candidate, is also conducting phase 2 and 3 human clinical trials of the candidate in India.