Patients with HIV-associated unintended weight loss were shown to gain more weight, more rapidly when taking a daily regimen of megestrol acetate concentrated suspension 575 mg/5ml than those patients receiving megestrol acetate oral suspension 800 mg/20ml according to results of a pilot study conducted Par Pharmaceuticals presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, D.C.

According to a company release, in this 12-week study involving 63 patients, both treatment groups demonstrated an increase in body weight; however, the MA-CS 575 mg/5 ml group showed a greater and earlier increase in body weight than the MA-OS 800 mg/20 ml group. There was a 10 per cent increase in the mean body weight from baseline in patients taking MA-CS compared to a 6 per cent increase from baseline in body weight for those taking MA-OS. Further, statistical differences in body weight gain were seen between treatments by week 1 and were observed for the majority of time points through week 12 in favour of MA-CS.

"Despite advances in antiretroviral therapy, significant weight loss remains a common and serious complication for individuals infected with the AIDS virus. This study demonstrated that, for patients taking MA-CS 575 mg/5 ml, the increase in body weight was greater and occurred earlier than those taking MA-OS 800 mg/20 ml. When treating AIDS-associated unintended weight loss in patients, increasing body weight may help improve the patient's sense of well-being," commented Christine Wanke of the Tufts University School of Medicine and the senior author on the study.

This study utilised a concentrated suspension of megestrol acetate, MA-CS 575 mg/5 ml, formulated using NanoCrystal Technology. MA-OS 800 mg/20 ml is an appetite stimulant approved by the FDA for the treatment of anorexia, cachexia, or an unexplained, significant weight loss in patients with a diagnosis of AIDS. Earlier this year, the US Food and Drug Administration (FDA) approved Megace ES for the same indication as MA-OS 800 mg/20 ml.

Megace ES, a concentrated megestrol acetate oral suspension formulated using the same NanoCrystal Technology used to formulate MA-CS 575 mg/5 ml, is bioequivalent to MA-OS 800 mg/20 ml in the fed state. In unfed conditions, the absorption of Megace ES is substantially less affected by food than is MA-OS 800 mg/20 ml. Megestrol acetate formulations utilising NanoCrystal Technology have increased absorption, allowing for a smaller dose and volume than the MA-OS formulation.

In addition to body weight, the study also explored caloric intake, body composition and appetite over the 12-week treatment period. The caloric intake trended higher and the increase occurred sooner for MA-CS 575 mg/5 ml compared to MA-OS 800 mg/20 ml. The increase in both lean body mass and fat mass were similar between the two groups and appetite scores increased comparably in both groups, as well. Adverse events were comparable between the two treatment groups.

NanoCrystal Technology is a trademark of Elan Pharma International Limited.

Par Pharmaceutical Companies Inc. develops, manufactures and markets generic drugs and innovative branded pharmaceuticals for specialty markets.