COLUMBIA, Md. ( TheStreet) -- Osiris Therapeutics ( OSIR) "disappeared" important data when the company announced results Monday from a mid-stage study of its stem cell therapy Prochymal in heart attack patients. Naturally, Osiris didn't come out and tell investors that it was issuing a misleading press release on the Prochymal heart attack study. Instead, the company claimed the study was a success. That's not true. Figuring out Osiris' deception wasn't that difficult if you know how to parse the language of clinical trial results and look at independent sources of information for the truth. Ride along with me as I pick apart Osiris' statements regarding the Prochymal heart attack study. Interpreting clinical trial results with a skeptical eye is a crucial tool for all biotech investors, so apply these skills universally whenever a drug or biotech company tries to convince you that its drug works. Hopefully, you'll find most companies are telling the truth, but sadly and too often, bullish pronouncements about boffo clinical trial data are just spin jobs ginned up to plaster over problems and bad data. Here's what Osiris issued Monday: Osiris Therapeutics, Inc. announced today interim one-year results from its groundbreaking clinical trial evaluating Prochymal (remestemcel-L) for the treatment of patients experiencing first-time acute myocardial infarction. The trial is the largest study of allogeneic or "off-the-shelf" stem cells ever conducted in heart attack patients. A total of 220 patients were given a single infusion of either Prochymal or placebo through a standard intravenous line within seven days of an acute heart attack. Not much to quibble with here except it's helpful to know that Osiris enrolled the first heart attack patient to this study in April 2009, so it took more than three years to complete and report "interim" results. ClinicalTrials.gov a great, independent source of clinical trial information, by the way lists the completion date for this study as December 2011, so Osiris appears to be reporting results six or seven months late. Osiris: Cardiac MRI assessments were conducted for six months following infarct to evaluate cardiac remodeling. Cardiac MRI is a precise and commonly used method of measuring cardiac changes in clinical trials. MRI assessments were conducted for six months after heart attack patients were enrolled and treated with either Prochymal or a placebo, but Osiris purports to be reporting interim, one-year results. When were the MRIs conducted in the Prochymal trial? Osiris doesn't specify, which clouds the reported results, especially if MRIs were not conducted at 12 months follow up. Osiris: Patients receiving Prochymal had significantly less cardiac hypertrophy, as measured by cardiac MRI, compared to patients receiving placebo (p less than 0.05). Patients treated with Prochymal also experienced significantly less stress-induced ventricular arrhythmia (p less than 0.05). Cardiac hypertrophy and ventricular arrhythmia are indicators of pathological remodeling following heart injury and provide insight into the mechanism by which mesenchymal stem cells attenuate heart injury following a myocardial infarction. This is the paragraph where Osiris claims positive results based on Prochymal beating placebo across two efficacy endpoints. Sounds impressive except none of the Prochymal benefits disclosed by Osiris are predefined endpoints in the phase II trial.