UPDATE 4-India's Zydus Cadila seeks approval for its 3-dose COVID vaccine

(Adds details from media briefing, quotes from executive)

BENGALURU, July 1 (Reuters) - Indian drugmaker Zydus Cadila said on Thursday it has applied for emergency use approval of its three-dose COVID-19 vaccine that showed efficacy of 66.6% in an interim study and could become the second home-grown shot if regulators consent.

Managing director Sharvil Patel said the company hoped to be producing 10 million doses a month by mid-August.

Although coronavirus infections have dropped from a devastating peak in April and May that strained healthcare facilities, experts have warned of a third wave, saying widespread vaccination is one of the best pandemic defences.

“We are currently only focusing our efforts on making sure we can make doses available for India,” Patel told a virtual press briefing. Approval for the shot would mean it would become the fifth vaccine authorized for use in the country.

Zydus said here the efficacy result is based on an interim analysis of a late-stage trial of more than 28,000 volunteers nationwide, including nearly 1,000 subjects in the age group of 12 to 18.

Immunogenicity data for the adolescent children subset will be submitted in the next four to six weeks, Patel said.

The drugmaker has also submitted data evaluating a two-dose regimen for the shot.

If approved, ZyCoV-D will be the world’s first DNA vaccine, Zydus said, as it makes use of a portion of the genetic code - DNA or RNA - in the SARS-CoV-2 virus to stimulate an immune response against its spike protein.

DNA vaccines differ from other approved COVID-19 shots, which are based on new mRNA technology such as in those from Pfizer and Moderna, and established technology like viral vectors, as with AstraZeneca.

Zydus said its study coincided with the peak of India’s second wave of infections and affirmed its efficacy against new mutants, especially the Delta variant.

Reporting by Anuron Kumar Mitra in Bengaluru, Editing by Sherry Jacob-Phillips, William Maclean