There was some treatment information during the conference that got my attention, one being MK-0518 an integrase inhibitor. Although just a year ago entry inhibitors that aim to prevent HIV from latching onto CCR5 receptors on the surface of the immune-system cells seemed to be the next big development for treatment, setbacks in clinical trials of the drugs dampened that enthusiasm. In this article I'll focus on MK-0518.
MK-0518 will need to be used in combination with other drugs. Clinical trials will evaluate its effect in combination with other drugs, including those currently approved for the treatment of HIV.
This new drug holds promise for HIV-positive patients who have taken other anti-HIV drugs in the past. Because MK-0518 targets HIV differently than currently available drugs, chances are that most people living with the virus -- regardless of their treatment history -- will likely benefit from using it.
The second part of the study enrolled 198 HIV-positive people, including 30 participants enrolled in part one of the study. The patients were to take one of the four doses of MK-0518 or Sustiva® (efavirenz). All patients in the study also received Viread® (tenofovir) and Epivir® (lamivudine). After 24 weeks of therapy, 85% to 95% of patients taking the MK-0518 regimen saw their viral loads reduced to less than 50, regardless of which dosing group they were in. In the Sustiva group, approximately 92% of patients experienced viral load reductions to less than 50 CD4 cell counts increased in all patients after 24 weeks or treatment. This study will follow patients for a total of 48 weeks.
A phase IIb study enrolled 167 HIV-positive participants, most of whom had evidence of resistance to drugs in three available classes (NRTIs, NNRTIs, and PIs). Patients were randomly assigned to one of three doses of MK-0518 (200, 400, or 600 mg twice daily), or placebo, in combination with a regimen of currently approved anti-HIV drugs. After 16 weeks of treatment, up to 72% of the patients receiving MK-0518 (most notably those receiving 600 mg twice daily) had viral loads below 50, compared to 16% of the patients who took placebo.
Phase III studies of MK-0518 have been started. An expanded access program (EAP) was initiated in September.
To qualify for the MK-0518 integrase inhibitor program, patients must have documented resistance or intolerance to at least one drug in each of the three major classes of anti-HIV medications - nucleoside analogues (NRTIs), non nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs).
Patients who qualify must not be adequately suppressing viral load on their current anti-HIV regimen and be at risk of clinical or immunologic progression. Their physician must determine that they need such an investigational medication to construct a potentially viable regimen.
To be eligible, patients must be at least 16 years old.
The safety and efficacy of MK-0518 has not been established. To increase the likelihood that patients will respond to this new experimental treatment, patients are encouraged to optimize their current regimen when beginning therapy with MK-0518. To do this, it is recommended that patients failing their current regimen receive at least two new antiretroviral medications to which their virus is still sensitive.
Eligible patients will be able to use MK-0518 with any available antiretroviral medications, including other medications available through expanded access research programs sponsored by other manufacturers after review and approval by the sponsor. Patients are ineligible if they are currently or were previously participating in a clinical trial with MK-0518. They also are ineligible if they are taking any medications prohibited by the study protocol, including Phenobarbital, phenytoin, and rifampin.
Until there is a cure KEEP SAFE!!
George Burgess is the Early Intervention Service Assistant of AIDS Survival Project. firstname.lastname@example.org.