(Reuters) - India's drug regulator has knocked back a proposal from Dr Reddy's Laboratories Ltd <REDY.NS> to conduct a large study in the country to evaluate Russia's Sputnik-V COVID-19 vaccine and has asked it to first test the vaccine in a smaller trial.
The recommendations by an expert panel of the Central Drugs Standard Control Organisation (CDSCO) noted that safety and immunogenicity data from early-stage studies being conducted overseas is small, with no inputs available on Indian participants.
India's move comes as a setback for Russia's plan to roll-out the vaccine even before full trials show how well it works, while pushing back its efforts to win approval for the vaccine in the country that leads the world on average number of new infections.
India is expected to overtake the United States over the next several weeks as the country with the world's largest number of cases.
The Russian Direct Investment Fund (RDIF), which is marketing the Sputnik V, and Dr. Reddy's Laboratories last month announced their partnership to run clinical trials and distribute the vaccine in India.
Russia was the first country to grant regulatory approval for a novel coronavirus vaccine, and did so before large-scale trials were complete, stirring concerns among scientists and doctors about the safety and efficacy of the shot.
RDIF and Dr. Reddy's did not immediately reply to Reuters' requests for comment outside business hours.
(Reporting by Manojna Maddipatla in Bengaluru; editing by Ankur Banerjee and Anil D'Silva)