Despite a frantic effort to rush Ebola vaccines through testing during a deadly epidemic, Merck & Co. will fall short of its goal to file its candidate for FDA approval this year, the company confirmed Tuesday. Merck is now aiming for next year.

While the company is "committed to developing and seeking approval for our Ebola vaccine as quickly as possible," Merck spokeswoman Pamela Eisele said via email, the drugmaker expects to file for approval at a "major regulatory agency in 2018." Merck is working with the FDA and European Medicines Agency on its filings, she added. 

The delay could jeopardize a $5 million advance purchase commitment from Gavi, the global vaccine alliance, that was announced early last year. The deal was contingent on Merck filing for approval by the end of 2017, the organization said at the time. Gavi representatives couldn't immediately be reached to comment on the development. 

Merck didn't immediately respond to a request for comment about the filing delay's potential to affect Gavi's $5 million purchase commitment.

As the drugmaker pushes for licensure, Merck back in July won important regulatory milestones for its vaccine from the U.S. FDA and the EMA, thanks to strong clinical data; both will bring additional regulatory support.

"The company is working with several partners to gather, validate and compile the data needed to support regulatory filings," Eisele said in an email to FiercePharma. "We are engaging with regulators through Priority Medicine and Breakthrough Therapy designations in the EU and U.S., respectively." 

Despite the fact Merck will miss its own filing target, Eisele noted that the R&D timeline for the shot is progressing much faster than the typical 10- to 20-year period typically required for drugmakers to develop immunizations. In recent years, global emergencies such as Ebola and Zika have put certain projects in the fast lane as governments and pharma companies respond to deadly outbreaks. Both of those disease outbreaks have now waned, making testing vaccines even more difficult. 

After Ebola killed more than 11,000 people and subsided in Western Africa, vaccine experts worried that the work could go unfinished and that priorities would shift to other projects. 

But Merck is still advancing its program and Eisele said the company is working with the World Health Organization and global charity Médecins Sans Frontières, plus countries in Africa, "to enable access to the investigational V920 vaccine, if needed, in the event of an outbreak prior to licensure." 

Meanwhile, some industry watchers have voiced frustration that the emerging disease vaccine development process is reactive. Many groups have begun teaming up to conduct research ahead of potential outbreaks. Governments, nonprofits and industry joined together this year to form the Coalition for Epidemic Preparedness Innovations for just that purpose. The group is initially working on the MERS-CoV, Lassa and Nipah viruses.