No abstract

Existing obesity therapies are limited by safety concerns and modest efficacy reflecting a weight loss plateau. Here, we explore combination therapy with bupropion (BUP), a putative stimulator of melanocortin pathways, and an opioid antagonist, naltrexone (NAL), to antagonize an inhibitory feedback loop that limits sustained weight reduction. In vitro electrophysiologic experiments were conducted to determine the extent to which BUP+NAL stimulated hypothalamic pro‐opiomelanocortin (POMC) neurons in mouse brain. A subsequent study further characterized the effect of combination BUP+NAL treatment on food intake in lean and obese mice. Finally, a randomized, blinded, placebo‐controlled trial in obese adult subjects was conducted. Randomization included: BUP (300 mg) + NAL (50 mg), BUP (300 mg) + placebo (P), NAL (50 mg) + P or P+P for up to 24 weeks. BUP+NAL stimulated murine POMC neurons in vitro and caused a greater reduction in acute food intake than either monotherapy, an effect consistent with synergism. Combined BUP+NAL provided sustained weight loss without evidence of an efficacy plateau through 24 weeks of treatment. BUP+NAL completers diverged from NAL+P (P < 0.01) and P+P (P < 0.001) at week 16 and from BUP+P by week 24 (P < 0.05). The combination was also well tolerated. Translational studies indicated that BUP+NAL therapy produced synergistic weight loss which exceeded either BUP or NAL alone. These results supported the hypothesis that NAL, through blockade of β‐endorphin mediated POMC autoinhibition, prevents the classic weight loss plateau observed with monotherapies such as BUP. This novel treatment approach (BUP+NAL) holds promise for the treatment of obesity.

One hundred eighty-nine patients with rheumatoid arthritis were entered into a prospective, controlled, double-blind multicenter trial comparing placebo amd methotrexate (MTX).721 bles measured, including joint paidtenderness and swelling counts, rheumatoid nodules, and patient and physician assessment of disease activity. MTX treatment demonstrated statistically significant improvement over placebo in patients with anemia, elevated erythrocyte sedimentation rate, and rheumatoid factor. However, nearly one-third of the patients receiving MTX were withdrawn for adverse drug reactions, of which elevated levels of liver enzymes was the most common. Pancytopenia occurred in 2 patients taking MTX. All adverse drug effects resolved without sequelae. MTX appears to be effective in the treatment of active rheumatoid arthritis but requires close monitoring for toxicity.

NB caused gradual sustained weight loss over 48 wk; NB32 and NB16 demonstrated greater weight loss in the intent-to-treat population due to lower attrition rates. Further study is needed to demonstrate long-term efficacy and safety of NB.