Research into virus continues

Third COVID-19 vaccine effort quietly underway at Pitt

The public has known for months now about two efforts at the University of Pittsburgh to create a vaccine that would help end the worldwide COVID-19 pandemic and get the nation back to normal.

One, overseen by Paul Duprex at Pitt’s Center for Vaccine Research, would use a measles vector technology in partnership with an Austrian company, Themis, that was just acquired last week by the global pharmaceutical company Merck, in large part because of its work on a COVID-19 vaccine. The project got another boost this week when the federal government chose Merck as one of five companies whose projects were chosen for extra funding.

The other Pitt vaccine effort, announced at a news conference in April, is being led by

Dr. Andrea Gambotto and Dr. Louis Falo and features a novel way to deliver the vaccine using a microneedle array.

But, quietly, a third vaccine effort has been ongoing at Pitt with little notice, no news conference and no pending purchase by a global pharmaceutical company.

This effort, led at Pitt by William Klimstra in partnership with Tiba Biotech, a 2-year-old company from the Boston area, is not aimed at competing to be one of the first vaccines to market, as Mr. Duprex’s work still could be.

The vaccines at Pitt are just a few of several COVID-19 vaccines being developed worldwide.

This third vaccine effort uses a novel method of creating a molecule with synthetic RNA — or ribonucleic acid — inside of it that theoretically would trick the body into thinking it was being attacked by the real coronavirus — without giving a person a version of a live virus, as most existing vaccines do — and potentially making it safer and more potent than other RNA vaccine efforts already underway.

Mr. Klimstra and Tiba officials say they are taking the long view that of the more than 100 vaccine projects worldwide the ones that succeed may have problems because of safety issues that they hope to solve.

“What’s needed here is a very large multi-pronged approach to vaccine development,” Mr. Klimstra said. “Because right now we just don’t know what’s going to be effective. Safety is really the key here.”

The technology they are using — an RNA-based vaccine — is probably the best known of all the vaccine efforts in the United States thanks to the success of Moderna Therapeutics, a Cambridge, Mass., company whose COVID-19 vaccine effort is the furthest along of any in the country in Phase 2 human clinical trials.

Jasdave Chahal, cofounder and chief scientist at Tiba, concedes he isn’t trying to win the race to the vaccine.

“We’re not going to beat any of the other guys. [We are a] tiny startup. We don’t have any illusions that we’re going to be the ones to bring a vaccine to save the world” this year, he said. “Our motivation though is we’re going to learn things about the virus in the process. Any biotech company, I think, has a responsibility: If we discover things, report it.”

That’s not to say that they don’t harbor hopes that their vaccine effort will succeed eventually.

“We also don’t know how long the COVID crisis will go on,” said Dr. Christian Mandl, Tiba’s acting chief science officer and the person credited with bringing Pitt and Tiba together through his long friendship with Mr. Duprex and Mr. Klimstra. “One potential scenario is that this goes on for quite a number of years, that we have vaccines that are OK but have room for improvement. And then of course, let’s say the Moderna vaccine is working, and one says, ‘Oh wouldn’t it be good if it was a little more potent, or the pain of injection was less?’ Maybe that’s where we come in.”

The basic premise of all of these RNA vaccine efforts is that RNA takes the instructions of DNA — or deoxyribonucleic acid — to make proteins that tell our cells what to do. For vaccines, the proteins, hopefully, tell the cells to begin an immune response powerful enough to fight off a disease.

Companies like the RNA approach for several reasons, including that it is easy to make synthetic RNA in a laboratory. Another advantage is that outside of the testing leading up to creation of the RNAbased vaccine, they never have to handle a virus itself, as most existing vaccine manufacturers do, because they use an attenuated, or weakened, form of the virus itself to create an immune response in their vaccine.

Identifying problems

The RNA vaccine approach has been underway for a decade now, and Tiba believes it has identified two major problems with it that it wants to solve.

There are many ways that an RNA molecule can be designed to get into a cell; nearly all of the major RNA vaccine efforts use the same construction: lipid nanoparticles.

In lipid nanoparticles, the positively charged lipid, or fat, molecules are mixed in with the negatively charged RNA and given a shell of other lipid-like molecules that allow it to slip easily into cells.

While that has been shown to deliver the RNA into the cells, Mr. Chahal said two big problems occur during the delivery of the molecule: First, the construction does not seem to allow for delivery of as much RNA as researchers would like; second, the cells can be irritated by the lipid nanoparticles.

If a cell is irritated by a molecule, “the first thing the cell does is shut down RNA translation,” he said. “So that’s a big problem that the RNA delivery field has been struggling to overcome.”

“So our company was founded on the premise that we’re going to start the delivery problem fundamentally,” he said.

Beginning when he was still getting his doctorate at the Massachusetts Institute of Technology, Mr. Chahal and his colleagues created a different type of molecule.

They still use lipids on the core of the molecule to help it slip inside the cell. But instead of using lipids inside the molecule, they use dendrimers, which are big, branched, highly charged molecules with tails on their end that are hydrophobic, meaning they don’t mix well with water, which allows them to stick even better onto the RNA.

Inside the molecule, the dendrimers appear to mix well with the RNA “almost like you’re putting Velcro onto a piece of yarn, little bits of Velcro bit by bit, and then the RNA gets spooled up and wrapped up and wrapped up, so you get a particle packed with RNA,” Mr. Chahal said.

“And if you consider lipid nanoparticles, I think of them like bubbles, our particles are more like wrapped up balls of yarn; the RNA is moving densely packed inside of them,” he said. “We want to get as much RNA payload per particle as possible, and it looks like we achieved that.”

The company is at a very early stage of its development with this approach. But early testing with mice did not show any inflammatory response and “it seems like our molecules are gentle,” he said.

Help from Pitt

Turning that novel idea into a working vaccine is where the partnership with Pitt helps enormously.

Mr. Klimstra’s work focuses on the study of mosquito-borne viruses like yellow fever, chikungunya and eastern equine encephalitis (sometimes called sleeping sickness).

He had been developing an alpha-virus-based vector in his lab that is itself a variation on the typical RNA method used by Moderna and others, using a defective virus RNA that carries out the RNA replication needed to create an immune response.

“Our hopes are that it would be more immunogenic than the Moderna-type approach,” he said. “Because of the higher levels of expression in the cells that receive the RNA and then the fact that the replicating RNA is actually a signal to our immune response of a virus infection, and so you get an enhancement of many aspects of the immune response associated with replication of an infecting virus.”

Putting Tiba’s work together with Mr. Klimstra’s seemed like an ideal combination, Dr. Mandl said.

Mr. Chahal said working with Pitt and Mr. Klimstra “radically changed what we did in the company.”

While Tiba had been trying to do all of the vaccine work on its own, Mr. Klimstra was already doing many of the same steps, too.

“We were able to just drop all of that,” he said. “And we turned our attention to working with all of Pitt’s RNAs, instead of duplicating efforts.”

So now, while Tiba will continue work on the delivery system, Mr. Klimstra has begun setting up work for possible testing of the vaccine on nonhuman primates.

To get their partnership moving, Mr. Klimstra was able to convert an existing National Institutes of Health grant for work on eastern equine encephalitis into work on a coronavirus vaccine, something the NIH has allowed during the pandemic.

His application to do that was approved just last week, allowing him to use about $1 million he already had been awarded in a grant to work on the project with Tiba. He should have the money in a few weeks.

One of the other issues that he is tackling is whether one of the other current, dominant ideas for a COVID19 vaccine — triggering the spike protein in the virus to illicit an immune response — will be effective, or, as some fear, it could lead to enhancement of disease.

Along with everything else that has to be solved to make a vaccine that potentially could be given to billions of people, such safety issues are paramount, he said.

“This is one of the reasons that it’s going to take longer than people are comfortable with to get an actual vaccine into the marketplace, or available to people, because we have to ensure there are not side effects like this in the vaccine,” he said. “And that kind of testing is what’s going to take a long time.”