At the 2013 IAS conference, Dr Timothy Henrich reported on the progress of the two ‘Boston patients’, both of whom received chemotherapy and stem-cell transplants for blood cancer lymphoma — one three, and the other five years ago. Now, after ceasing antiretroviral treatment for 15 and seven weeks respectively, neither man has any trace of HIV in their blood.
Many in the HIV sector are now using the term ‘remission’ instead of ‘cure’ as a more accurate way of describing these results. Most are unwilling to as yet guarantee that HIV can be eradicated from every cell in the body for all time.
Nevertheless, if you add together the ‘Berlin patient’, the ‘Mississippi baby’ and these two ‘Boston patients’, the world of HIV is now tracking the progress of four patients who have potentially been 'cured' of HIV.
Unlike the Berlin patient (Timothy Brown), the excitement surrounding the Boston patients can be justified by two key differences. According to Dr Henrich, they undertook gentler chemotherapy, plus the stem-cell transplantation they received was not from a donor who had naturally resistant immune cells to HIV (found in less than 1% of the population). This means that a potential HIV cure has just become safer (i.e. less chemo) and more widely applicable to everyone (i.e. easier to find compatible donors).
One hypothesis proposed by Dr Henrich as to why the gentler chemotherapy and simpler stem-cell transplantation worked is that the donor immune cells were sufficiently different from that of the host immune cells; this led to the donor immune cells bumping out and eliminating the host’s immune cells where HIV was hiding.
HIV eradication research will require further research and willingness by patients to place their health and their lives on the line. Not all of these will be personal success stories.
There was little publicity surrounding the case of 12-year old Eric Blue. On 23 April this year he received an experimental treatment at the University of Minnesota for HIV and leukaemia but died nine weeks later. The donor providing his stem cells was not only compatible but also had the advantage of immune cells genetically resistant to HIV. While not yet conclusive, testing has revealed that Eric had cleared both his HIV and leukaemia.
According to his doctor Michael Verneris, Eric "absolutely needed to have this transplant".
Unfortunately, he developed graft-versus-host disease, a complication from stem cell transplantation where the donor immune cells attack various tissues of the body. While the disease can be treated, "he had an especially bad form of it", said Dr Verneris.
It seems cruel that any young person would have to endure HIV from birth, develop leukaemia, become free of both, and then die weeks later. That is why it is important to acknowledge the pioneering medical contribution of people like Eric Blue.
The history of HIV is full of dignified men and women who have been prepared to participate in medical experimentation for the benefit of the greater good.
It is important to also acknowledge the doctors who are prepared to step out of their standard treatment guidelines and explore options for improvements in HIV treatment and prevention.
Innovation is rarely riskless. To the courageous people like Eric Blue, who accept the risks and nevertheless embark on the journey to advance human medical science, we salute you.
The International AIDS Society conference comes to Melbourne in July 2014. Progress on all these potentially cured patients will undoubtedly be widely sought and reported. How wonderful if we could lay claim to our own HIV-cured Australian?