Also see "Aware of the Heart," "Black People Experience Less Viral Suppression," "Long-Acting Drug in Development," "Once-Daily Pills Improve Outcomes," "Zinc Finger Gene Therapy Continues to Show Promise," and "Reyataz and Kidney Stones." Some abstracts available at www.natap.org.
The investigational drug S/GSK1265744 is a long-acting injectable with hopes for once-a-month dosing. Shionogi and GlaxoSmithKline reported finding limited cross-resistance between S/GSK1265744 and two similar medications already on the market (the oral drugs Isentress and elvitegravir, which is available in the recently approved Stribild). All three medications are integrase strand transfer inhibitors, or INSTIs. The researchers reported a "potential for a high barrier to [drug] resistance" and that their data suggests "a favorable profile for both HIV treatment and PrEP" (pre-exposure prophylaxis, or prevention).
HIV-positive people taking Norvir-boosted Reyataz with Truvada were able to maintain their viral load suppression out to 24 weeks when switching out the Truvada and replacing it with Epzicom and dropping Norvir. The switch also allowed them to significantly improve their biomarkers for potential kidney and bone toxicity. Truvada is associated with the potential for such toxicity. Also, their HDL (good cholesterol) increased. While the results were positive, 24 weeks is a short period of time. Nearly 300 individuals participated in the study, with nearly 200 switching meds; the study will continue out to 48 weeks.
GS-7340 is a next-generation prodrug of tenofovir (brand name Viread, found in Truvada, Atripla, Complera, and Stribild). These popular formulations containing tenofovir make it one of the most widely prescribed HIV medications in the country. It is metabolized inside human cells to take its active form. The GS-7340 prodrug avoids this step in the absorption of tenofovir. Researchers reported test tube results showing superior antiviral potency with GS-7340 as well as synergy with other HIV medications, with higher intracellular levels for the prodrug.
MK-1439 represents a sort of blast from the past: it's a non-nucleoside reverse transcriptase inhibitor (NNRTI), or from the second class of HIV medications that were developed. The class includes Intelence, Edurant (found in Complera), Sustiva (found in Atripla), and Viramune-XR. Merck & Co. researchers reported drug resistance data comparing MK-1439 to the NNRTIs on the market, finding the potential for it to work when current drugs don't.