A drug used to treat cancer could also wipe out HIV-infected cells.
A letter published in Annals of Oncology reveals that a lung cancer patient in France experienced a “drastic and persistent decrease” in the reservoirs of cells where HIV hides after being treated with nivolumab.
The researchers, led by Professor Jean-Philippe Spano, head of the medical oncology department at Pitie-Salpetriere Hospital AP-HP in Paris, say the discovery could have implications for all HIV patients.
The reservoirs of HIV-infected cells lie dormant in the immune system in organs and cannot be eliminated by anti-retroviral therapy. It means if treatment is stopped, the virus starts to replicate and infect more cells.
HIV primarily infects CD4 T cells and when they are attacked by HIV they become infected and exhausted, which means they are less able to fight the infection.
Professor Spano said specific drugs that appear to re-activate the latent HIV-infected cells could have the effect of making them visible to the immune system, which could then attack them.
Drugs that inhibit immune check-points such as PD-1 are well known among cancer specialists as being efficient at restoring immune defences.
Prof Spano said: “It was thought, but until now not demonstrated, that inhibitors of immune check-points could, in a similar way, wake up dormant HIV-infected cells and also the immune defences against the virus.”
The discovery comes after the research team administered the nivolumab PD-1 inhibitor to a 51-year-old male patient with non-small cell lung cancer after he relapsed following surgery and chemotherapy for his tumour.
Prof Spano says that the patient, who also has HIV, received 31 injections of nivolumab every 14 days since December 2016.
When he was first treated with nivolumab, HIV was undetectable in blood samples. It increased progressively up to day 45 before decreasing again. At the same time T cell activity increased, with a marked increase in the activity of another T cell, CD8, from day 30 to 120.
By day 120 the reservoirs of HIV-infected cells “showed a drastic and persistent decrease”, says the letter.
Professor Spano said: “In this patient we observed, as expected, both a re-activation of HIV and an increase in CD8 T cell responses against HIV, which resulted in the drastic decrease in the HIV reservoir, thus leading to a sustained reduction of the HIV reservoirs.
“This is the first demonstration of this mechanism working in humans. It could have implications for HIV patients, both with and without cancer, as it can work on HIV reservoirs and tumour cells independently. The absence of side effects in this patient is also good news, and suggests this could be an optimum treatment for HIV-infected patients with cancer.”
However, he remains cautious about the result because in another case there was no decrease of the HIV reservoir.
Amélie Guihot et al. Letter to the editor: Drastic decrease of the HIV reservoir in a patient treated with nivolumab for lung cancer. Annals of Oncology 1 December 2017; doi:10.1093/annonc/mdx696
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