Sanofi Stops Work on Two Zika Vaccines

Drugmaker Sanofi SA has ended its development of two Zika virus vaccines, citing a decline in new infections and limits on U.S. government funding, in a move that illustrates the challenges in sustaining research in emerging infectious diseases after major outbreaks subside.

A division of the U.S. Department of Health and Human Services, the Biomedical Advanced Research and Development Authority, or BARDA, informed the French company's Sanofi Pasteur vaccine unit in August that the agency had reviewed the Zika projects it was funding and "decided to focus on a more limited set of goals and deliverables," Sanofi said in a statement posted on its website Sept. 1.

As a result, the company said it is discontinuing its development of the Zika vaccine it had been testing in partnership with the U.S. Army since last year. The Walter Reed Army Institute of Research originally developed that vaccine, which contains an inactivated virus, and Sanofi had been helping to study whether it was safe and effective in people, with a $43 million BARDA grant.

Jon Heinrichs, associate vice president and Zika project leader at Sanofi, said in an interview that Sanofi's development of the Army vaccine was going to take several years longer than expected because of the need to evaluate new vaccine doses manufactured by the company, and because of the decline in infection rates. He said BARDA was unable to commit to additional funding to accommodate the longer timeline.

"The driving forces behind this are change in epidemiology and lack of additional funding," Mr. Heinrichs said.

Sanofi had been part of a big push by drug companies and government and private researchers to find new vaccines and medicines after the mosquito-borne virus spread rapidly in Brazil and elsewhere in the Americas in 2015 and 2016. The virus was linked to causing defects in many babies and fetuses of women infected by the virus.

But the rate of new infections has declined, and in November 2016 the WHO lifted the public-health emergency for the outbreak it had declared earlier last year.

The decline in infection rates may prolong vaccine development time lines because researchers may have to enroll more people in clinical trials to get enough data to demonstrate safety and efficacy, said Anthony S. Fauci, director of the National Institute of Allergy and Infectious Disease, in an interview.

Development of vaccines for such unpredictable pathogens is "a risky business," Dr. Fauci said. "It's unlike the development of drugs and therapeutics for predictable diseases. It's tenuous."

A similar scenario unfolded with the Ebola virus epidemic that killed thousands in West Africa in 2014. Companies, governments and nonprofits raced to find drugs and vaccines, but by the time they were ready to test them in the field, the epidemic had waned and it became harder to assess their safety and efficacy. Three years later, no Ebola drug or vaccine has been approved by health regulators. Merck & Co. continues to develop an Ebola vaccine and has contributed doses to a U.S. government stockpile, and plans to file for U.S. regulatory approval by the end of this year.

"Zika remains a public health threat and we remain committed to working with industry on Zika diagnostics and vaccines," BARDA Director Rick Bright said in a statement Wednesday. He said the agency continually evaluates the projects it's funding, which led to revising the contract with Sanofi. He added that BARDA continues to fund the development of several Zika diagnostics and blood-screening tests, and three other vaccines, including those developed by Takeda Pharmaceutical Co., Moderna Therapeutics and Brazil's Butantan Institute.

Several other companies and government agencies also continue to develop Zika vaccines, including Inovio Pharmaceuticals Inc.

This is the second Zika vaccine Sanofi has shelved, Mr. Heinrichs said Wednesday. Late last year the company suspended development of a live-virus vaccine because it would have taken many years to develop it, and the company wanted to focus on the Walter Reed-developed vaccine, he said. Sanofi hadn't previously disclosed shelving that vaccine.

There is no approved vaccine for Zika, a virus first identified seven decades ago. Zika has infected more than 220,000 people in the Americas since 2015, with hundreds of thousands more suspected cases; most of them occurred before this year. Most cases have been in Latin America, but some were reported in the U.S., including more than 200 transmitted via mosquito bites in the U.S. and nearly 50 via sexual contact.

The NIAID is testing its own experimental Zika vaccine in a study in Puerto Rico, Texas and several South American countries. If infection rates remain low, researchers may have to enroll up to 5,000 study volunteers, but if infections increase the study could have as few as 2,600 participants, Dr. Fauci said. He said the study may complete enrollment by mid-2018.

Dr. Fauci of the NIAID said Zika's pattern is unpredictable, and it could go under the radar for a few years before coming back.

Sanofi said Friday that BARDA planned to modify its contract with the company so development would be "indefinitely paused" but could be restarted if another epidemic emerges.

Sanofi's collaboration with the U.S. Army drew criticism after the Army said last year it planned to grant exclusive patent licenses to Sanofi for the Zika vaccine. Knowledge Ecology International, a nonprofit, objected to the plan because it didn't include a cap on the price Sanofi could charge for a vaccine if it reached the market. In response to the proposed patent deal, Sen. Bernie Sanders, a Vermont independent, proposed a law that would require federal agencies to secure fair-pricing agreements in exchange for license and rights deals.

Mr. Heinrichs of Sanofi said "we were quite frankly disheartened by the fact we entered into this with the best of intentions to help out in the face of an epidemic. We really felt the brunt of a lot of negative publicity and political pressures" over the patent issue. He said Sanofi's position was that it was too early to discuss pricing.

Write to Peter Loftus at peter.loftus@wsj.com

(END) Dow Jones Newswires

September 06, 2017 17:56 ET (21:56 GMT)