Bill and Melinda Gates are betting on this biotech in the race to develop a Zika vaccine

Moderna Therapeutics aims to turn human bodies into factories that make proteins to fight infections and disease like the Zika virus.

Stéphane Bancel's plans are nothing short of disrupting the entire biomedical industry — and with it the way your body and everyone else's are protected against a variety of diseases. As CEO of Moderna Therapeutics , Bancel helms a biotech company that claims it can direct cells to develop whatever proteins it chooses, in effect turning a body's own cells into miniature factories capable of developing the therapeutic proteins necessary to fight infections and heal diseases.

It's an audacious ambition, and one that has attracted the attention and money of large pharmaceutical companies, the Bill and Melinda Gates Foundation and the federal government.

"We modeled Moderna to mimic biology by giving your body the instructions for your cells to make the proteins you need to protect you," said Bancel.

If successful, Moderna's methods could lead to therapeutic drugs and myriad vaccinations being produced more quickly at a lower cost. It's a pitch that has made the Cambridge, Massachusetts-based Moderna Therapeutics, currently valued at close to $5 billion, the most valuable private biotech company in the United States. Its stockpile of $1.9 billion in cash has been raised from financing and partners that include pharmaceutical giants Merck and AstraZeneca and the Bill and Melinda Gates Foundation.

In addition, the U.S. Department of Health and Human Services has provisionally agreed to up to $125 million to underwrite Moderna's attempt to make a vaccine for Zika, the mosquito-borne virus linked to the birth defect microcephaly. In December the company kicked off its clinical study and began dosing human subjects.

Vaccine development 2.0

But the process at the heart of Moderna's potentially disruptive approach to medicine is one that has been tried before and abandoned by other pharmaceutical companies for its complexity. And according to an encompassing investigation published by STAT News last September, the company's recent pivot to the crowded field of vaccine development has left some industry observers wondering if Moderna's technology is ready to make previously unavailable therapeutic treatments finally obtainable.

"People are pretty excited about the potential for mRNA vaccines," said Anna Durbin, professor of international health at the Johns Hopkins Bloomberg School of Public Health. "But right now we don't have the human data to see if they're going to live up to their potential."

Traditionally, the biotech industry manufactures drugs outside of the body that are then ingested or injected. Moderna wants to flip the script by using messenger RNA, or mRNA. Inside everyone, there are about 22,000 proteins. Our DNA contains the instructions to produce each one of these 22,000 proteins. But when our body needs to make more of a specific protein, it produces a copy of the instructions for producing that one protein. That copy is mRNA — think of it as the software to the hardware of DNA.

By injecting synthetic mRNA into the body, Moderna says it can direct the body's cells to make proteins, turning cells themselves into drug-producing facilities. For vaccines the approach is the same. Injecting the mRNA associated with Zika should prompt the body's cells to produce proteins that Zika needs to replicate and survive. When presented with those proteins, the immune system will react as it does to the natural virus, producing antibodies to fight future infections — even though a person hasn't really been infected with Zika. Through Moderna's mRNA technology the antibodies needed to fight a true Zika infection will already have been made.

"We get cells to make proteins from within in a way that the biotech industry, which makes those proteins outside of the human body, can't," said Dr. Tal Zaks, Moderna's chief medical officer.

Medical controversy

Up until last month, this calculation was one Moderna made boldly, but without much in the way of supporting data. At the end of April, the company, founded back in 2010, published clinical data from its first human vaccine trial in the journal Molecular Therapy. That trial involved Moderna testing an mRNA-based vaccine for the flu. In this particular case, the goal was to direct cells to create a protein that triggered an immune response to help protect against future infections of the H10 influenza virus.

"[These data] provide early evidence that our mRNA vaccine technology is safely and effectively directing the body's cells to produce and express viral antigenic proteins and elicit high levels of immunity that are expected to protect against viral infections," Zaks said in a press release.

Companies that have tried and failed with their own mRNA efforts often cite accurately delivering RNA molecules as one of the chief challenges. Without being wrapped in some sort of biological delivery mechanism, mRNA has a difficult time getting directly to cells. But as STAT News pointed out, some of the delivery mechanisms used to get mRNA to cells can have dangerous side effects for patients.

If the data holds up, then Moderna has managed to find a way to safely transport protein-producing mRNA into cells, which could turn vaccine production on its head. To produce a new vaccine, Moderna wouldn't need a viral sample. Instead, all it would need is the virus's genetic sequence, which it plugs into the coding region of mRNA. From there, Moderna would synthesize a portion of the virus and, in theory, begin making a vaccine in a matter of weeks.

"Vaccine development is hugely complex, hugely long and hugely expensive. With mRNA it allows us the chance to pursue more rapidly and widely a huge range of vaccines," said Mike Watson, president of Valera, Moderna's internal division, focused on producing vaccines for infectious diseases like Zika.

Still, there are reasons to view with caution what Moderna is doing, despite the seemingly incredible promise of the technology.

The era of personalized medicine

The Bloomberg School's Durbin recalls the buzz that materialized about 20 years ago over DNA vaccines, which promised the same advances as mRNA-based vaccines: quickly and cheaply made vaccines that triggered really good immune responses. But DNA vaccines didn't produce as good of an immunogenic response in humans as they did in mice during testing. And one of the main issues with DNA vaccines was ensuring that the DNA was delivered to the right spot inside the body.

"We had a similar sense of excitement and possibility with DNA vaccines that haven't quite panned out the way we hoped," Durbin said. "People will be very interested in these Zika vaccine results."

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It remains to be seen whether mRNA-based vaccines, like the one Moderna is currently testing for Zika, can stand on their own. There are unresolved questions: How many doses of an mRNA-based vaccine will be needed to get a good immune response? How long will that immune response last?

And yet, Moderna is plunging ahead with its work on mRNA-based vaccines. Through its partnership with Merck, the company plans to develop personalized cancer vaccines. The Gates Foundation has pledged up to $100 million to develop mRNA-based vaccines for infectious diseases; the first $20 million is being used by Moderna to develop mRNA-based antibody therapeutics to help prevent HIV infection.

Coming online in the middle of 2018 is a manufacturing facility in Norwood, Massachusetts. Bancel said it will be a factory capable of producing 1,200 products a year, where Moderna will make the mRNA required for a slew of vaccines. Scientists eager for testable mRNA will just have to enter, through an online automated system, the specific protein they want to direct a cell to make; vials filled with mRNA will then get shipped.

"My bet is that in the next five years, we'll have two times as many drugs in the clinic than anybody else in the world," said Bancel. "We're just warming up now."

— By Andrew Zaleski, special to