Mark started his research career working on avian retroviruses in Montreal, mainly with cell and in vivo studies. Not long after the AIDS epidemic was underway, Mark went to the Gallo lab at the National Cancer Institute at the NIH to learn molecular biology and focus on the newly identified retrovirus causing AIDS. He was recognized quickly for his passion not only for his science, but also for life in general. These characteristics never changed, but he returned to Montreal as an investigator of HIV. He sustained this focus throughout his whole academic career, which remained located at the McGill University AIDS Centre at the Montreal Jewish General Hospital.
An early focus of his research after returning to Montreal was HIV drug resistance, which continued for the remainder of his career and represented his major research contributions. Shortly after the first report of HIV drug resistance, he investigated the enzymology of reverse transcriptase and the impact of various critical resistance mutations. He examined the impact of drug resistance on viral fitness in vitro, but more recently he investigated resistance to the integrase inhibitor dolutegravir in a macaque model. His major focus was nucleosides and reverse transcriptase, but over the years he investigated protease inhibitors and integrase inhibitors. His studies with the greatest impact involved lamivudine (3TC). His lab was one of the labs that independently reported the selection for resistance mutations to lamivudine at M184 of reverse transcriptase, and he went on to characterize the impact of those mutations on the enzyme, the virus and clinical trial outcomes.
What distinguished Mark was that, in addition to his contributions as a Ph.D. laboratory investigator, he was a passionate social and political advocate. He was president of the International AIDS Society in 2000 when the IAS had scheduled its first meeting to be in the heart of the epidemic (Durban, South Africa), rather than in Europe or North America, where more easy travel and most investigators were located. This transformative meeting addressed the AIDS denialism of Peter Duesberg and South African President Thabo Mbeki. Moreover, Mark played a central role in engaging the participation of Nelson Mandela. Mark was not always known for diplomacy, but his heart was in the right place and his passion was evident. In 2006 at the XVI international AIDS conference in Toronto, Mark challenged his Canadian Prime Minister Harper with the statement, “We are dismayed that the prime minister of Canada, Mr. Stephen Harper, is not here this evening... Mr. Harper, the role of Prime Minister includes the responsibility to show leadership on the world stage. Your absence sends a message that you do not regard HIV/AIDS as a critical priority, and clearly all of us here tonight disagree with you.” Mark was an outspoken advocate for the rollout of treatment in low and middle income countries and, specifically, for the use of the integrase inhibitor dolutegravir in that role.
Whether you were at a meeting discussing the enzymology of HIV drug resistance or access to treatment in low and middle income countries, Mark stood out as passionately involved. The issue under discussion was critically important and Mark always had a strong opinion.