No vaccine is yet available for respiratory syncytial virus (RSV), which causes lung infections that, while usually mild, can be deadly for very young children. Biotech startup Meissa Vaccines, which aims to fill that treatment gap, announced today it raised $30 million to fund early-stage clinical trials for its experimental RSV vaccine.
Morningside Ventures, a private equity and venture capital firm founded in Hong Kong in 1986, was the sole investor in the Series A financing, which brings Meissa’s fundraising total to nearly $34 million. The startup is a resident company at Johnson & Johnson Innovation’s facility JLABS in South San Francisco.
Meissa’s work builds on vaccine development methods initially devised at Emory University by Meissa CEO Martin Moore, who co-founded the startup in 2014. Moore says scientists have worked for decades so far to produce an effective vaccine for the respiratory virus.
“An RSV vaccine has been elusive,’’ Moore tells Xconomy in an interview.
Vaccine developers face this challenge: Mere exposure to the naturally occurring strain of the RSV virus does not leave a person with lasting immunity to later infections, Moore says. So Moore create a custom RSV strain for Meissa’s vaccine, using a combination of genetic engineering and synthetic biology techniques. The changes had to make the new strain more powerful at raising an immune response, while hampering its ability to multiply broadly in the body and cause illness, he says. The engineered virus also had to be easy to grow in cell cultures, producing a sufficient yield of vaccine.
Moore, who worked on the RSV bioengineering project for 10 years, says Meissa’s vaccine is the product of two main changes. First, viral genes were modified to lower the microbe’s production of two proteins that actually suppress the immune response of the infected host, such as a human being. Second, genetic tinkering enhanced the immune system-boosting power of a biomolecule called the F protein. The genetic modifications maintain more of the protein molecules in their most effective form, though some still flip into a different shape that is less immunogenic.
The resulting vaccine, dubbed MV-012-968, is a live virus strain, which is attenuated (or weakened) to prevent it from making the host sick. Meissa is planning a Phase 1 safety and immunogenicity trial in healthy adults by the end of this year.
The vaccine would be administered by drops into the nose. If all goes well, the attenuated virus would replicate in the nose—not the lungs—and would stimulate an immune response in the body. It would not cause a fever or symptoms of a viral respiratory infection.
Depending on the results of the safety trial, Moore says, further early-stage trials will be designed to explore the potential of the vaccine to protect infants. The first of those trials would test the vaccine in older children; a following trial would test it in babies. Moore says Meissa is also considering trials in elderly people, who are also vulnerable to serious infections with RSV.
If Meissa’s vaccine is as effective as the company hopes, it would likely be recommended for mandatory universal coverage worldwide, Moore says. “RSV kills 2,000 babies a week worldwide,’’ Moore says.
Vaccine manufacturers have been grappling with public resistance among some parents to vaccinating their children, based on fears that the shots could cause side effects or other diseases. (In general, the U.S. Department of Health & Human Services advises Americans that “serious side effects from vaccines are extremely rare.’’) If the Meissa vaccine eventually wins regulatory approval, how would Moore persuade parents that their children should receive it?
“I think public health officials have already made that case,’’ Moore says. “Vaccines have saved more lives than any other treatment in human history.’’