CDSCO Panel Asks Zydus Lifesciences to Revise Phase I Protocol for Inactivated Chikungunya Vaccine

New Delhi: The Subject Expert Committee (SEC) on Vaccines, under the Central Drugs Standard Control Organisation (CDSCO), has directed Zydus Lifesciences to revise and resubmit its Phase I clinical trial protocol for the company's inactivated chikungunya vaccine candidate, citing gaps in preclinical and immunogenicity data.

This came after Zydus Lifesciences presented the Phase I/II clinical trial protocol of the study titled "A prospective, randomized, double-blind, placebo-controlled, phase I/II clinical trial to evaluate the safety and immunogenicity of the Chikungunya vaccine candidate of M/s. Zydus Lifesciences Ltd. in healthy participants."

The committee noted the following points:

1. Firm has developed Inactivated Chikungunya Vaccine based on the Chikungunya parent virus seed (DEN-AFP-SV130030).

2. The firm has completed an acute toxicity study and a repeat-dose toxicity study before selecting a human dose.

3. The firm has not furnished any lethal dose challenge study report in any animal model and/or in non-human primates for confirmation of the human protective dose of this proposed novel inactivated vaccine developed for chikungunya.

4. The firm has not furnished any developmental and reproductive toxicology (DART) study report.

5. The firm has not furnished immunogenicity data for selection of protective dose.

6. Based on the toxicity studies, firm has proposed to conduct Phase I study followed by Phase II study as single dose or two doses study based on data of Phase I trial.

7. As the vaccine is developed from chikungunya virus strain from new source , it was opined that firm should separate Phase I and Phase II protocol and establish safety and tolerability of the vaccine in the first-in human study.

8. The firm should include exploratory endpoint to compare the immunogenicity in subgroups identified seropositive in the baseline which is currently excluded in the protocol.

9. The safety follow up for PhaseI and Phase II should be increased to 6 months / 1 year for adequate safety data for new vaccine.

10. The firm should submit the revised Phase I protocol to conclude the maximum and minimum dose for Phase II. Based on Phase I study report and high & low dose selection, the firm should submit Phase II protocol with adequate justification of sample size.

11. The firm should revise the Phase I protocol for estimation of anti-CHIKV antibodies by PRNT50 method as secondary objective instead of exploratory objective.

12. The firm should define the PRNT50 cutoff value.

13. The firm has proposed to conduct the immunological assessment at IRSHA, Pune, as central laboratory for which the firm is required to furnish the prior experience and capacity of the laboratory for the development and generation of bioanalytical test results of new vaccines that are standardized, consistent and reproducible.

In view of the above and after detailed deliberation, the committee recommended that the firm should submit a response with respect to the above observations, including protective dose selection criteria for the new vaccine.

Accordingly, the expert panel suggested that the firm should submit the revised Phase I protocol only for further deliberation.