VANCOUVER, British Columbia – With some positive early data for an antibody to block the COVID-19 virus, San Diego-based Sorrento Therapeutics Inc. is now looking to test a product in a few dozen intensive care patients by the end of July or early August and move into a much broader pool of patients by October.
“We believe the data is spectacular,” said Henry Ji, Sorrento’s chairman, president and CEO. “Right now, we have the compound.”
On May 15, the company reported that low concentrations of its STI-1499 antibody completely blocked the SARS-CoV-2 virus from interacting with the ACE2 receptor. Ji said he is optimistic its treatment will not only get quick approval but also be rolled out in just a few months.
Sorrento plans to market STI-1499 as Covi-guard and to include it in a three-molecule cocktail it is developing with Mt. Sinai Health System dubbed Covi-shield.
Sorrento started by screening about a billion antibodies from its G-Mab library to come up with several hundred potential antibodies with binding capabilities and strong signals. The next step was to look for neutralizing capabilities within the smaller pool of several hundred candidates and pitting the antibodies vs. the receptor, looking for those with the ability to block the virus from getting into the cells. That narrowed the list down to about a dozen possibilities.
The next step was to test the potential hits with the actual virus and monkey cells. The virus, the antibodies and the healthy cells were mixed together and left for four days. At high concentrations, all the potential antibodies blocked the virus but, as the concentration levels dropped, the most effective antibodies emerged.
“Out of the 12 we sent in, only two or three really suppressed the virus after four days,” Ji said. “You want to see, after four days, at which concentration do you have 100% no virus infections… After four days, we found only one antibody that gives complete prevention of the viral infection.”
That antibody is the one Sorrento is developing as STI-1499. Investors heralded the company’s initial results with glee, tripling the value of the company’s shares (NASDAQ: SRNE). Share prices have come down significantly since, to $5.17 at the close of trading on May 27, but they are still worth almost twice what they were prior to news of the progress.
The antibodies identified by Sorrento appear to provide protection only as long as they are in the body, unlike vaccines that can generate lifetime immunity. The challenge is to extend the amount of time they stay in the body. At the moment, it looks like a 200-mg dose could provide a year of protection. And, when included as part of a cocktail, the protection could be greater.
“That is why we are so excited about this whole thing,” said Ji. “This protein alone can do the job but if you added a couple more it can be a cocktail.”
Despite the excitement at the company and the promising data, it is early days. Still, the development of treatments and vaccines for COVID-19 are moving fast, and regulators are helping to move things along.
“What we are hoping for is to have a final package to go to the FDA for approval for the initial treatment of patients in the ICU, so that we could treat patients end of July, August timeframe,” said Sorrento’s vice president of regulatory affairs and quality, Mark Brunswick. “That will be a very early stage drug.”
“It is a little bit accelerated because we would be using a much earlier stage of antibody production than we would normally use,” Brunswick said.
The company expects to be able to move into a phase II study with a fully commercial and ready product for less sick patients or even for use as a prophylactic made in the company’s facility in San Diego by September or October. It takes about 45 days to make a dose and that can be pushed down to about a month, the company said.
“The reason everything is being accelerated is because lots of people have platforms that can be adapted to COVID-19. It’s what we are doing with our platforms,” Brunswick said. “Plus, the agencies are desperate, or somewhat desperate, to have an approval out there.”
“The science behind it is very solid,” said Brunswick. “Often, drugs fail when they go into a patient because the metabolism of the body is not the same as what would be predicted from an animal model or from an in vitro study.
“The advantage of what we are doing is that we’re taking an antibody that is to a protein that is not normally present in a person. So, the antibody should not be interacting with anything in the normal body,” Brunswick said. “Therefore, there should be no adverse effects associated with administrating our antibody. It is only against the virus… given the 100% inhibition that we’re seeing in vitro, that should pan out in human service as well.”
The company is now making enough doses for an initial study involving around 40 patients. While that study is going on, Sorrento plans to begin expanding production to about 200,000 doses. And, if everything goes well, the company could work with its partner in China to drastically expand production capacity. Sorrento’s China partner can produce as much as 10 million doses per month.
Sorrento works in China with Hong Kong-listed Mabpharm Ltd. Mabpharm has 30,000 square meters of production facility in Taizhou and Shanghai. In March, Sorrento and Mabpharm entered an exclusive license agreement for the development and commercialization of the ACE-MAB fusion protein to potentially treat COVID-19.
Ji also said Sorrento is working on vaccines for COVID-19. Although, to date, the company has not produced any vaccines, he said it is working on a fairly straightforward process.
“We have a lot of expertise in the company and we want to do a lot of things in parallel. We have expertise in the antibody side with multiple compounds in human testing,” Ji said. “The key in looking for something is the complete prevention of viral infection. Whether a vaccine or whether that’s a therapeutic antibody, that’s the key…. The key is, are they preventing the virus infection completely? If not, you’ve got a problem.”