Results from Astrazenca's Pegasus study of its blood-thinning Brilinta treatment received a cool reaction from the market on Monday, though analysts at UBS maintained their positive outlook for the product.The bank said it still sees upside to consensus forecasts for Brilinta's sales despite the mixed study results.UBS kept a 'buy' rating and 5,500p target price for the stock, which was fluctuating between gains and losses in morning trade.A study of 21,000 patients using Brilinta alongside a low-dose aspirin showed a reduction in cardiovascular death, myocardial infarction or stroke compared to placebo, though also more bleeding.The broker highlighted feedback from the American College of Cardiology where results were presented at the weekend: "Some ACC panelists argued that Pegasus showed that patients with atherosclerosis risk should remain on dual anti-platelet therapy (Brilinta + aspirin) probably indefinitely, whereas other panelists were more cautious, pointing to the bleeding risk."Nevertheless, the bank said that the usage of Brilinta for patients beyond 12 months is still "favourable"."Physicians we spoke to argued that an individualized approach is required based on a patient's atherosclerotic and bleeding risk, and that best candidates for Brilinta/dual anti-platelet therapy beyond 12 months would be those patients that arrive at the 12 months' time point already on Brilinta."Thus, Pegasus seems unlikely to drive broad uptake in secondary prevention, but instead should provide a key tool in AZN's marketing toolbox that should help to extend treatment duration in Acute Coronary Syndrome patients after hospital discharge, to 12 month (PLATO) and beyond (PEGASUS)."The stock was 0.4% lower at 4,539.5p by 10:30.