A step closer to an HIV cure. No rebound of HIV in two patients who stopped taking their
HIV medication after stem cell transplantation for a hematological disease
Medical
experts have found no evidence of an infectious virus for months in two HIV
patients who stopped their antiviral medication. Both patients underwent stem
cell transplantation as part of their cancer treatment. The transplanted donor
cells had a gene defect (CCR5delta32mutant), which results in the absence of
one of the critical entry gatekeepers that HIV generally needs to infect cells.
One of the patients has been without antiretroviral treatment for 18 months, so
experts are especially optimistic regarding a possible cure. The other case of
HIV was undetectable after 3,5 months without antiviral medication.
Thus far,
only one person in the world, ‘the Berlin patient’, has been cured of HIV. Although
traces of HIV were found, HIV never rebounded and he is now celebrating his
12th anniversary of being cured. The transplanted cells from a CCR5delta32 donor
most likely protected his immune system. He also received aggressive chemotherapy,
total body irradiation and two stem cell transplants. For over a decade, the
HIV field has been puzzled regarding which
of these factors were essential for his cure.
Today,
Professor Ravi Gupta of the University College London and the University of
Cambridge, presented the breaking news of a new case with a possible HIV cure
at the international Conference on Retroviruses and Opportunistic Infections
(CROI) in Seattle and will be published in Nature today. His London patient has
not experienced HIV rebound during the 18 months after he stopped taking his
antiviral medication. This is the longest adult HIV remission after stem cell transplantation
since the Berlin patient. Usually, when HIV+ individuals stop treatment, the virus rebounds within
the first month.
A second
potential cure from HIV after stem cell transplantation will be presented by
Dr. Björn Jensen from Düsseldorf University. This patient
stopped using his HIV medication for a shorter period of 3,5 months and has also
remained HIV free. In previous cases of antiretroviral interruption after a stem cell transplant without the
CCR5 Delta 32 mutation, the virus rebounded at month 3, 8 and 10, respectively.
The patients
were investigated by internationally renowned researchers. Both patients are registered
to the IciStem program. IciStem is a
joint venture of collaborating researchers and clinicians who share their
expertise on HIV cure and stem cell transplantation to gain insight into the
mechanisms of HIV eradication.
In both
patients only traces of HIV DNA were detected with the most sensitive
techniques available to date, similar to the case of ‘the Berlin patient’. According
to the principal investigators of IciStem, P. Annemarie Wensing, from the University Medical Center of
Utrecht (The Netherlands), and Javier Martinez-Picado, from
the IrsiCaixa AIDS Research Institute (Barcelona, Spain), these cases support
the further investigation of CCR5 related gene therapy.
The cases
show that, even with one transplant, mild cancer chemotherapy and without
radiation, remission may be achieved.
Today, 39 patients
who are registered with the IciStem program have received a transplant. IciStem
has the largest program to investigate HIV cure following stem cell transplantation,
and has identified more than 22,000 donors with the rare CCR5delta32 gene defect.
IciStem investigator Gero Hütter, who was the physician who performed the
transplant on the ‘Berlin patient’. was instrumental in this aspect of the program . IciStem is funded by the Foundation for AIDS
Research (amfAR).
