MANILA - The Food and Drug Administration has permanently revoked the certificate of product registration (CPR) of anti-dengue vaccine Dengvaxia, which has been blamed for a slump in immunization rates.

The previous Aquino administration inoculated hundreds of thousands of schoolchildren with the world's first dengue vaccine.

French drug maker Sanofi, however, disclosed in December 2017 that the vaccine can trigger more severe symptoms for those who have not had dengue, prompting the government to stop the sale of Dengvaxia and its use in the state immunization drive.

Dengvaxia's product registration was scrapped due to Sanofi's persistent failure to submit post-approval commitment documents, the FDA said Tuesday.

"Its brazen defiance of FDA’s directives and its continued failure to comply leaves us no other recourse but to impose the maximum penalty of revocation of the CPRs covering the Dengvaxia products,” FDA Director General Nela Charade Puno said.

The revocation of the Dengvaxia's CPR makes its importation, sale and distribution illegal, said the FDA.

Authorities disagree publicly over whether Dengvaxia could have contributed to the deaths of several children.

The issue has spawned a drop in immunization coverage in the country to 40 percent last year, from an average 70 percent in recent years.

Metro Manila and 4 other regions are currently grappling with outbreaks of the vaccine-preventable measles.

Former president Benigno "Noynoy" Aquino III and several of his Cabinet secretaries were charged last year with plunder, malversation and graft before the Office of the Ombudsman for their involvement in the Dengvaxia program.

The House health committee earlier this month also recommended the filing of criminal and administrative charges against the officials.

JAPANESE VACCINE

Another dengue vaccine by Japan's Takeda Pharmaceuticals is undergoing clinical trial, Health Secretary Francisco Duque III told ANC.

Takeda last month said its experimental dengue vaccine appears to be safe and effective at preventing all 4 types of the mosquito-borne disease.

The company said no significant safety concerns have emerged to date with the vaccine called TAK-003.

Takeda did not disclose how the vaccine performed in people who had never been previously exposed to dengue.

The firm collected blood samples from 20,000 children aged 4 to 16 from Asia and Latin America who participated in the Phase III TIDES trial. The study looked at the vaccine’s safety and efficacy both in children who had been exposed to dengue and those who had not.

Takeda said it will release full details of how the vaccine fared at 15 months after the first dose in a peer-reviewed journal as quickly as possible.

The vaccine is administered in 2 doses 3 months apart. The first efficacy results include 11 months of follow-up.

Part 2 of the trial, which includes another 6 months of patient data, will review how the vaccine performed in each of the four different types of dengue, as well as its performance according to prior dengue exposure and the number of participants who contracted severe dengue.

Those 2 parts will form the basis of Takeda’s filings seeking regulatory approvals. A third part of the study will evaluate long-term safety by following participants for another 3 years.

Dr. Rajeev Venkayya, president of Takeda’s vaccines business, told Reuters that the upcoming publication will include preliminary data on the vaccine’s performance against each dengue strain and data on prior dengue exposure of trial subjects.

The first safety problems with Sanofi’s vaccine only became apparent in the third year after vaccination. After the Sanofi experience, some experts believe governments will require several years of follow-up data before incorporating Takeda’s vaccine into mass vaccination campaigns.

Venkayya would not speculate on how much follow-up regulators or health authorities will require, but said, “I do think it’s going to be more than one year.”

While Sanofi’s vaccine was based on a Yellow fever virus with dengue genes added in, TAK-003 is based on a weakened dengue 2 virus plus genes from the 3 other dengue types. Some infectious disease experts think the all-dengue design may trigger a broader immune response.

With a report from Reuters