At a time when Bangladesh is battling the worst dengue outbreak in the country’s history, at least two local pharmaceutical companies have expressed interest in developing the first indigenous tetravalent live-attenuated vaccine, TV005.
The International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b)could not conduct trial phase-3 of the vaccine due to insufficient funding and absence of necessary license of domestic vaccine companies.
Investigators from icddr,b and the Larner College of Medicine at the University of Vermont (UVM) conducted the phase-2 trial of the dengue vaccine candidate, TV005, that demonstrated safety and immune responsiveness in both children and adults, without significant side effect except mild rash on the body.
Experts said the vaccine can play a vital role in reducing mortality from the mosquito-borne disease.
However, no domestic company has a license to develop this type of vaccine.
The icddr,b on Wednesday held a meeting with the ministry concerned regarding necessary funding and approval from the World Health Organization (WHO).
Regarding the cost for phase-3 trial, icddr,b said it will need several million dollars to conduct the trial.
An official of the Ministry of Health told Dhaka Tribune that the government will collaborate with the icddr,b to develop the vaccine and the ministry has already received some proposals from local pharmaceutical companies who are interested in developing the vaccine.
However, icddr,b is doubtful of the capabilities of the local companies in this regard as they would have to obtain the necessary license from the National Institute of Health (NIH).
Requesting anonymity, a senior scientist of the icddr,b told Dhaka Tribune that icddr,b is also working with the NIH in the matter of obtaining the license to manufacture dengue vaccine. The local companies will have to negotiate directly with the NIH, the scientist added.
Second trial findings
The single-dose tetravalent dengue vaccine, TV005, is well tolerated and immunogenic for all four serotypes DEN1, DEN2, DEN3 and DEN4. A single dose of this vaccine can give protection against dengue and develop antibodies in the human body, the trial findings suggest.
Investigators from UVM and icddr,b Executive Director Dr Tahmeed Ahmed said that with three years of follow-up, the single-dose tetravalent vaccine was well tolerated and immunogenic for all four serotypes.
When can it be used in Bangladesh?
The India-based pharmaceutical company Panacea Biotech in collaboration with the Indian Council of Medical Research (ICMR) has taken initiatives to conduct phase-3 trial of the vaccine already.
icddr,b suggests even after the completion of the phase-3 trial, it might take some more time to be fully sure that the vaccine will be safe for the human body.
However, another version of the vaccine, TV003, went through trial in Brazil which is aimed to prevent dengue strain-1 and 2. The vaccine is also awaiting approval from the WHO.
icddr,b suggests an alternative approach to combat dengue, which includes using Bacillus thuringiensis israelensis (Bti) and Ulbakia (laboratory-born mosquito) in the country until such a vaccine is available in market.
Senior scientist and Chief Researcher of icddr,b Dr Rashedul Haque said that although Japan and Indonesia have registered two vaccines before, they are not widely effective.
The second phase trial found the vaccine to be 100% effective for persons with previous exposure to any of the serotypes 1 to 3, and about 87% effective for serotype 4.
On the other hand, for a person with no previous dengue infection, the vaccine is 70% effective for Serotype 1, 99% for serotype 2, 94% for serotype 3, and 88% for serotype 4.
In the trial, 194 volunteers received the TV005 vaccine or placebo over three years, beginning in 2016.
Dr Tahmid Ahmed said they want the vaccine to be produced in Bangladesh after all the trial stages.