ViroPharma (VPHM) is up about 60% this year and nearly half of that gain came in one day last month when rumors were swirling about potential buyout suitors. According to Bloomberg News, Sanofi (SNY) and Shire (SHPG) have shown interest in acquiring ViroPharma.Now that ViroPharma has earned a Zacks #1 Rank (Strong Buy), this pullback to $37 looks even more interesting than just a bull flag consolidation in the wake of the rumors.We'll look at the analyst estimates and recent EPS beats that have made VPHM a #1 in a moment, but first, here's the compelling chart with that big green candle on September 13 worth 11.7 million shares, which clearly indicates institutional accumulation...Orphan Drug SpecialistViroPharma develops and commercializes drugs specifically targeting unmet medical needs with particular focus on orphan diseases, which the FDA defines as rare conditions affecting less than 200,000 people, or that affect more than 200,000 persons but are not expected to recover the costs of developing and marketing a treatment drug. In essence, the FDA grants special "Orphan Drug Designation" status to drugs and biologics targeting these diseases.ViroPharma's key drugs include Cinryze for hereditary angioedema (HAE), Plenadren for the treatment of adrenal insufficiency (AI), Buccolam in Europe for the treatment of pediatric seizures, and Vancocin for the treatment of C. difficile- associated diarrhea (CDAD).ViroPharma’s growth story currently revolves around Cinryze, which is approved in the U.S. for routine prophylaxis against angioedema attacks in adolescent and adult patients with HAE.Cinryze accounted for 76% of total sales in 2012. In the EU, Cinryze received approval for routine prevention, pre-procedure prevention and acute treatment of angioedema attacks in adults and adolescents in 2011.Cinrzye has been granted marketing exclusivity by the U.S. Food and Drug Administration (FDA) until 2015 under the Orphan Drug Act.Meanwhile, an interesting candidate in ViroPharma’s pipeline is maribavir, being developed for the treatment of cytomegalovirus (CMV) infections in transplant recipients. ViroPharma received orphan drug designation in the EU for maribavir in June 2013 for the treatment of CMV in patients suffering from impaired cell mediated immunity.Maribavir was granted the same designation in the U.S. in May 2011 for the treatment of clinically significant CMV and disease in at-risk patients.Back to ProfitabilityViroPharma reports earnings Thursday October 24 before the market opens and last week some analysts were bumping up their estimates ahead of the event. These upward revisions, combined with recent big positive surprises in the previous two quarters, have all eyes set on the company's return to profitability next year.While the company's pipeline, earnings momentum, and chart all look good, Thursday's report could give large investors the confirmation they need about ViroPharma. A move above all-time highs at $41 will be the signal for many to keep accumulating shares.Kevin Cook is a Senior Stock Strategist for Zacks where he runs the Follow The Money portfolio.