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Alpha-immunotherapy – a new option for the treatment of HIV infections?

The news

European and American researchers believe that radiolabelled antibodies might eradicate the immunodeficiency virus-infected cells from a patient's body. Scientists have combined antibodies with radioactive payloads that deliver lethal doses of ionizing radiation to selectively target and destroy HIV infected cells. This hypothesis has been successfully tested in a joint project between the Albert Einstein College of Medicine in New York and the  JRC Institute for Transuranium Elements (ITU) as reported in the Public Library of Science[1]. These results provide first support for the concept that these antibodies labelled with radioactive substance (Bi-213) can be used for treatment of HIV. Pre-clinical development testing the efficacy and safety of this novel therapy approach are being undertaken in preparation of a Phase I clinical trial in HIV infected patients.

[1] Dadachova E, Patel MC, Toussi S, Apostolidis C, Morgenstern A, Brechbiel MW, et al. Targeted killing of virally infected cells by radiolabeled antibodies to viral proteins. PLoS Medicine. 2006, 3(11):2094-103.

The background

In a person infected with HIV, the symptoms of AIDS can be delayed or controlled with drug combinations such as highly active antiretroviral therapy (HAART). However, at the moment there is no cure for HIV infection or AIDS. Even in people for whom HAART is successfully controlling disease, HIV remains at very low levels in white blood cells, and is capable of infecting more cells if treatment is stopped for some reason or becomes ineffective because the virus has developed resistance.

Targeted alpha therapy (TAT) is a therapeutic technique used in cancer treatment as valuable alternative to chemotherapy and external radiation beam for a certain type of tumours. In the latest advancement of targeted alpha therapy of infections, it was found that HIV infected cells can be eliminated in vitro and in vivo by targeting viral proteins present at the surface of infected cells with radio-labelled viral protein-specific-antibodies.