The Hyderabad-based pharmaceutical firm had on October 13 reapplied to the Drugs Controller General of India (DCGI) seeking permission to conduct combined phase 2 and 3 human clinical trials of the vaccine in the country.

In its revised protocol, firm stated that the phase 2 trial would include 100 subjects, while the phase 3 would involve 1,400 volunteers, the sources said.

The subject expert committee (SEC) on COVID-19 deliberated on the application on Friday.

"Following deliberation, the SEC has recommended the grant of permission for the phase 2 clinical trial of the potential vaccine first. After they submit the safety and immunogenicity data of the first phase, they then would be allowed to proceed for the phase 3 of the trials," a source said.   The SEC had on October 5 asked the firm to re-apply stating it will have to conduct both phase 2 and 3 clinical trials and cannot directly hold phase 3 trial for the vaccine in India.  The Indian pharma giant has collaborated with The Russian Direct Investment Fund  (RDIF) to conduct clinical trials of the Sputnik V vaccine as well as its distribution.

Upon regulatory approval in India, RDIF shall supply to drug maker Dr Reddy's 100 million doses of the vaccine, the firm had said last month.

According to sources, it would be multi-centre, observer-blind, randomised controlled study.  

Meanwhile, the sources said the phase 3 trial of Sputnik V is underway in Russia since September 1 on around 40,000 subjects.

Sputnik V, a vaccine against coronavirus, has been developed by the Gamaleya National Research Center of Epidemiology and Microbiology and the RDIF. 

Currently two indigenously developed vaccine candidates, one by Bharat Biotech in collaboration with ICMR and another one by Zydus Cadila Ltd are in the phase 2 of the human clinical trials.

Pune-based Serum Institute of India, which has partnered with AstraZeneca for manufacturing the Oxford COVID-19 vaccine candidate also is conducting Phase 2 and 3 human clinical trials of the candidate in India.