A cannabinoid drug that was first developed by a group of Dalhousie University researchers in Halifax to treat inflammation may be a new contender in the fight against COVID-19.
The drug, called PPP003, would help prevent the onset of acute respiratory distress syndrome (ARDS), which causes death in severely ill COVID-19 patients.
“The drug will be targeting a symptom of COVID-19 inflammation. It’s not a vaccine and it’s not something that stops viral growth,” says Melanie Kelly, a pharmacology professor at Dalhousie University.
Kelly was one of the researchers at Panag Pharma, the small Halifax company that pioneered the drug a decade ago. The research on the drug’s efficacy in treating sepsis was largely done by one of Panag’s original founders, Christian Lehmann, in collaboration with other researchers.
Kelly is now chief scientific officer with Tetra Biopharma, which acquired Panag in May 2019.
Tetra Biopharma was planning to start clinical trials for the drug as treatment for a blinding eye disease. As the eye disease and COVID-19-induced ARDS are caused by similar processes in the body, the company decided to assess the drug’s efficacy for COVID-19.
They are now applying for the new COVID-19 research funds announced by the federal government in April. Kelly says she was excited with the new funding opportunities.
“It was a really bold move,” she says. “It encourages industry to work with academic researchers so that they will work on something that could potentially benefit those patients and allow us to know more about how this particular virus is different from others.”
The funds will help Tetra Biopharma accelerate the trials and find the most appropriate methods to deliver the drug to patients.
“Otherwise the company would be looking to continue to raise money to support its progressing clinical trials. It is a process to raise money and (producing the drug) is incredibly expensive.”
Kelly says PPP003 is the only cannabinoid drug she knows of that is seeking approval for COVID-19 clinical trials in Canada.
The PPP003 drug is not derived from cannabis. The active molecule in PPP003 is a small molecule made in the lab. It’s classified as a cannabinoid because it acts at a receptor, called Type II Cannabinoid Receptor (CBR2). The receptor is part of the cannabinoid family of receptors that are found on cells of all vertebrates.
“But (CBR2) is not the same receptor that gives you what people think of as the high from smoking cannabis or taking THC.”
The driving force behind the death of some patients who are very ill with COVID-19 may be a reaction of the immune system called “cytokine storm”.
Cytokines are molecules that are important for regulating the body’s immune response. But in a cytokine storm, cytokines are released in larger amounts than what is needed. This causes immune cells to attack healthy tissue leading to organ failure. When immune cells attack lung tissue, it can cause ARDS, a condition that prevents oxygen from reaching the rest of the body.
Some studies have found high levels of cytokines in the blood of hospitalized COVID-19 patients, who are the main target for PPP003.
Kelly expects that PPP003 will reduce cytokine levels, improving the outcome for those patients. The drug will be administered intravenously.
Another drug under clinical trials in Canada and other parts of the world, called tocilizumab, also acts on dampening the cytokine storm. The drug has been previously used in treating rheumatoid arthritis. Kelly says there’s no way to know if it will be useful for treating COVID-19 patients until the clinical trials are complete.
“I think having available drug candidates that we can draw upon in the hospital to fight this disease is an important thing,” she says.
There are now 25 clinical trials authorized in Canada in relation to COVID-19.
Since PPP003 is at an advanced stage of production, Kelly says they will be able to start clinical trials in the fall with results coming out late this year. Before that, the drug will be tested for safety.
If the pandemic dissipates by then, it will be difficult to find hospitalized patients to run the clinical trials for COVID-19. But PPP003 could still be useful.
“What makes PPP003 important is that ARDS is not unique to COVID-19, it occurs with lots of other viral and bacterial infections,” sha says. “It’s also possible that we would see a seasonal or second wave of COVID and we need to prepare for that.”