COVID 19 Research Q&A Series: Dr. Darrell Tan
Dr. Darrell Tan’s new COVID-19 clinical trial focuses on prevention, not treatment
Darrell Tan, MD, FRCPC, is an infectious diseases physician and clinician scientist at St. Michael’s Hospital in Toronto. He has received grants from CIHR’s 2019 Novel Coronavirus (COVID-19) rapid research funding competition, and other sources, to study the efficacy of an existing HIV medication in preventing COVID-19.
What is the context for your research and what are you focused on accomplishing?
Kaletra is a drug that we’ve been using safely for two decades to treat HIV and also as post-exposure prophylaxis (PEP) for uninfected people who have been exposed to the virus. Prior research suggests that Kaletra has some degree of activity against a protease in this new coronavirus, so we’ve designed a clinical trial to test it. We’re working to get a result by the end of the summer that will tell us whether Kaletra is an effective drug for use in preventing COVID-19.
Why is it important to focus on prevention?
At this time, there’s disproportionate attention on prevention interventions – only about 10 per cent of clinical trials related to COVID-19 are prevention-focused, with most of them focusing on treatment. Treatment is also extremely important, of course, but we’re unlikely to treat our way out of this pandemic.
You’re using ring-based design in this study. Can you explain how it works?
With a ring design, we identify an infected person and then identify their closest contacts. This constitutes a “ring” of exposed people around the infected person and those are the people who we’ll intervene with. The design of the trial uses these rings as the units of randomization, which means every person in a ring is randomized to the same group – the entire ring either gets the drug or does not get the drug.
How are you finding study subjects for the trial?
We’ve identified four clinical trial sites that have a lot of experience doing this kind of work. We’re working with collaborators such as public health authorities, hospitals and front-line clinicians, who will identify newly diagnosed individuals, engage their close contacts and enroll them in the study. We enrolled the first people on April 17.
Your timeframes have been tight. How have you managed to roll this out so quickly?
Clinical trials can easily take a year-and-a-half to set-up properly. This time, we’ve gone from an idea to our first enrollments within two months, mostly because CIHR, Health Canada, the ethics board we worked with and everyone else involved have worked overtime and weekends to get it done. It shows you what is possible.
What is your most optimistic outlook?
[It is] to see that Kaletra causes a significant reduction in the likelihood of someone being infected with COVID-19. One great advantage with this drug is that Kaletra is already on the market and widely available around the world. That would make it relatively easy to get into the hands of those who need it, if it’s shown to be effective.