The Subject Expert Committee (SEC) on Vaccine, which advices the Central Drugs Standard Control Organisation (CDSCO), has sought Zydus Life Sciences to submit revised phase I protocol with response to its various observations before considering the company's proposal related to the clinical trial of its inactivated Chikungunya vaccine.
The SEC was considering the company's proposal for a phase I/II clinical trial on 'A prospective, randomised, doule-blind, placebo-controlled, phase I/II clinical trial to evaluate the safety and immunogenicity of Chikungunya vaccine candidate' in healthy participants.
The Committee noted that the company has developed Inactivated Chikungunya Vaccine based on a Chikungunya parent virus seed and has completed acute toxicity study and repeat dose toxicity study before selecting human dose.
However, it said that the company has not furnished any lethal dose challenge study report in any animal model or in non-human primates for confirmation of human protective dose of the proposed vaccine. It has also not furnished any developmental and reproductive toxicology (DART) study report, and immunogenicity data for selection of protective dose.
It added that based on the toxicity studies, the company has proposed to conduct phase I study followed by phase II study as a single dose or two doses study based on data of phase I trial.
"As the vaccine is developed from chikungunya virus strain from a 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," observed the Committee.
The company should include an exploratory endpoint to compare the immunogenicity in subgroups identified seropositive in the baseline which is currently excluded in the protocol. The safety follow up for phase I and phase II should be increased to 6 months or 1 year for adequate safety data for the new vaccine.
It should also 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, added the Committee.
Zydus should also revise the phase I protocol for estimation of anti-CHIKV antibodies by Plaque Reduction Neutralization Test 50 method as secondary objective instead of exploratory objective and it should define the cutoff value for the test.
The company has proposed to conduct the immunological assessment at IRSHA, Pune as a central laboratory for which it is required to furnish the prior experience and capacity of the laboratory for development and generation of bioanalytical test results of new vaccines which are standardized, consistent and reproducible.
"...after detailed deliberation, the committee recommended that the firm should submit response with respect to the above observations including protective dose selection criteria for the new vaccine. Accordingly, the firm should submit revised phase I protocol only for further deliberation," said the Committee in its meeting held on September 24.
According to the National Centre for Vector Borne Diseases Control, under the Union ministry of health, the number of confirmed Chikungunya cases in the country has gone up from 9,756 in the year 2019, to around 17,930 in 2024. During the year 2025, a total of 1,741 cases has been reported till March, 2025.
Zydus has a pipeline of new vaccine products like Recombinant Hepatitis E, Inactivated Hepatitis A, Human papillomavirus (rDNA), Bivalent Typhoid and Paratyphoid A vaccine, Inactivated Chikungunya vaccine, and Recombinant Varicella Vaccine with an aim to cater to the requirements of both India and export markets.
According to reports, the company has entered into partnership with Japanese drug major Takeda Pharmaceutical in September, 2016, to tackle Chikungunya, an infectious disease prevalent in Africa, Asia and the Indian subcontinent. While the terms of the partnership were not disclosed, Takeda said that the partnership agreement covers early stage development through the final commercialization of the vaccine.
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