Pegylated interferon alfa-2a (PegIFN) may be an effective therapy for Kaposi's sarcoma (KS) that has not responded to antiretroviral treatment or chemotherapy, Dutch investigators report in the online edition of Clinical Infectious Diseases. Doctors in Rotterdam used PegIFN to treat ten HIV-positive people with KS that had not resolved with standard therapy. A complete or partial treatment response was observed in eight patients.
“Responses were durable until the end of follow up with a median PFS [progression free survival] of 2 years,” comment the authors. “Our study provides a strong rationale for further investigation of PegIFN in AIDS-KS.”
KS is the most common AIDS-defining cancer. First-line treatment is standard combination antiretroviral therapy and this achieves a complete response in most people.
However, cases of KS progression have been observed in the context of HIV treatment and a suppressed viral load. Moreover, many patients present with already extensive or progressing disease that requires additional chemotherapy on top of HIV treatment.
This chemotherapy can achieve good responses but carries a risk of immune reconstitution inflammatory syndrome (IRIS), drug interactions and unpleasant side-effects. “Treatment remains challenging, due to relapses, disease progression and treatment toxicity,” note the authors.
Interferon alfa is approved for the treatment of AIDS-related KS. The pegylated form of the drug (PegIFN) has superior efficacy and is less toxic. Doctors in Rotterdam therefore wanted to see if PegIFN in combination with antiretroviral therapy was an effective treatment for advanced KS that had not resolved with standard treatments.