NEW DELHI : Drug firm Zydus Cadila on Sunday said it has received DCGI approval to initiate Phase III clinical trials of its COVID-19 vaccine ZyCoV-D.The company will now be initiating Phase III clinical trial in around 30,000 volunteers, Zydus Cadila said in a statement.ZyCoV-D was found to be safe, well-tolerated and immunogenic in phase I and II clinical trials, it added.The phase II study of ZyCoV-D had been conducted in over 1,000 healthy adult volunteers as part of the adaptive Phase I/II dose-escalation, multi-centric, randomised, double-blind placebo-controlled study, the drug firm said.The trial has reviewed by an independent data safety monitoring board (DSMB) and reports were submitted to the Central Drugs Standard Control.