MARLEY SEAMAN AP Health Writer NEW YORK (AP) — Vivus Inc. said Wednesday its erectile dysfunction drug candidate avanafil met its main goal in a late-stage clinical study, as men who took avanafil experienced a greater improvement in their symptoms than patients who took a placebo. Vivus said all three doses of avanafil improved erectile function, which was the key goal of the study. The subjects who took avanafil were also more likely to have erections sufficient for sex, and more of them had successful intercourse, the company said. The data were presented at a health care conference in New York. Wednesday's results were from the first of four late-stage studies of the drug. There were 646 men in the trial, and they had had ED for at least six years. They were given avanafil doses of either 50 milligrams, 100 milligrams, or 200 milligrams or a placebo, and advised to attempt sex within 30 minutes of taking the drug. The subjects generally had moderate ED, according to a survey. After treatment, avanafil patients had mild to minimal dysfunction. The placebo group had lesser improvement and their symptoms still ranked as moderate, on average. Vivus, which is based in Mountain View, Calif., said it plans to file for marketing approval of avanafil with the Food and Drug Administration in late 2010 or early 2011. First, it will report results from the other three late-stage trials. Those include one safety study, one trial on men with diabetes, and one on men who have had their prostate glands removed. Vivus currently markets the ED drug Muse.