September 13, 2013

HIV Patients With Cancer Pose Tx Challenge

Published: Sep 12, 2013 | Updated: Sep 13, 2013

By Michael Smith, North American Correspondent, MedPage Today

Reviewed by F. Perry Wilson, MD, MSCE; Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

Action Points

  • This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
  • Note that this single-center, retrospective study demonstrated better outcomes when HIV patients with cancer were treated with raltegravir compared with protease inhibitors.
  • Be aware that, in the absence of a randomized trial, it remains unclear what the preferred regimen in HIV patients with cancer may be.

DENVER -- HIV patients with cancer should avoid antiretroviral therapy based on protease inhibitors (PIs) if possible, a researcher said here.

In a retrospective analysis, patients on a PI-based regimen had more side effects and were less likely to maintain anti-HIV efficacy 6 months after diagnosis, according to Harrys Torres, MD, of the MD Anderson Cancer Center in Houston.

On the other hand, patients taking a regimen based on either an integrase inhibitor (INSTI) or and non-nucleoside reverse transcriptase inhibitor (NNRTI) had fewer adverse events and better efficacy, Torres reported here at the annual Interscience Conference on Anti-Microbial Agents and Chemotherapy.

The issue is important, Torres said, because non-AIDS defining malignancies have been an increasing issue among HIV patients and now account for about 33% of all HIV-related deaths. Despite that, he said, there is little evidence pointing to the best HIV regimen for such patients.

To help clarify the issue, he and colleagues looked at the safety and efficacy of various HIV regimens among men who were treated for both cancer and HIV at MD Anderson over a 12-year period.

HIV regimens, in general, consist of a backbone of two nucleoside reverse transcriptase inhibitors (NRTIs) along with a PI, an NNRTI, or an INSTI. During the study, the only INSTI available was raltegravir (Isentress) but others are now on the market.

Of the 154 patients, 80% were male, 51% were white, and 58% had hematologic malignancies, including 42% with non-Hodgkin's lymphoma.

For this analysis, the researchers defined efficacy at 6 months as the absence of virologic failure or virologic rebound.

The NRTI backbone was combined with PIs for 37% of the patients, with NNRTIs for 32%, and with raltegravir for 19%, Torres reported. (The remaining 11% had other combinations, such as one drug from each class.)

Analysis showed that:

  • Side effects occurred in 35% of the patients getting a PI, in 14% of those getting NNRTIs, and 3% of those getting raltegravir, a trend that was significant (P=0.001).
  • The 6-month efficacy rates of raltegravir and NNRTI-based regimens were comparable at 96% and 97%, respectively.
  • The 6-month efficacy of PI-based regimens was 65%, significantly less than either of the other main regimens types ( P=0.005 and P=0.001).
  • Interruption of HIV therapy treatment was less common in patients receiving raltegravir than in those receiving PIs or NNRTIs -- 7%, 28%, and 26%, respectively.

The message of the study is that raltegravir is a safe choice for doctors who might not be completely familiar with all of the possible drug-drug interactions, commented Jean-Michel Molina, MD, of Saint-Louis Hospital in Paris, who was not involved with the research but who moderated a session at which it was presented.

In the complicated universe of drugs for cancer and drugs for HIV, most physicians are likely to be familiar with one area or the other, but not both, Molina told MedPage Today.

Picking the safest HIV drugs means choosing those least likely to increase the toxicity of chemotherapy, he said. In general, the HIV drugs will continue to be effective as long as they are taken, but if chemo toxicity is high -- causing nausea and vomiting, for instance -- it might interfere with patient adherence.

The reason PIs perform worse, Molina noted, is that they inhibit liver cytochromes, which can increase the toxicity of some cancer medications, so one option is to switch HIV regimens, perhaps to one based on raltegravir.

But if a patient is unwilling or unable to change, he said, another option might be to stop HIV therapy 24 hours before and after the administration of chemotherapy.

The study had support from Merck. Torres reported financial links with Merck, Vertex, Novartis, Astellas, and Pfizer.

Molina reported financial links with Janssen, ViiV Healthcare, Gilead Sciences, Bristol-Myers Squibb, and Merck, Sharp & Dohme.

Primary source: Interscience Conference on Anti-Microbial Agents and Chemotherapy
Source reference: Torres HA, et al "Efficacy and safety of antiretrovirals in hiv-infected patients with cancer" ICAAC 2013; Abstract H-1255.


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