I've received many positive reader emails about my first installment on biotech investing, and there was positive trial data from one of the companies I profiled later -- YM BioSciences (AMEX:YMI). So here are the biotech companies most popular with readers that are expected to report major catalysts in the form of clinical trial data and FDA decisions. These companies are expected to be on the move in the next nine months and have market caps ranging from around $100 million to just beyond $1 billion. Let's get to it.

For DOR BioPharma (OTC BB: DORB.OB), May 9 is fast approaching. That's when the FDA's oncology advisory committee decides whether to recommend that the FDA approve its experimental orBec treatment for gastrointestinal graft versus host disease in transplant patients (a serious, potentially fatal complication in which the body attacks itself). The Food and Drug Administration will make its decision on July 21. The drug is a unique oral formulation of the steroid beclomethasone that failed to meet its primary endpoint in phase 3 trials but did show a noticeable survival benefit upon longer-term follow-up. The advisory committee must consider whether the survival benefit is due to orBec or some other factor, because it wasn't the primary endpoint in the trials. My guess is that orBec probably has slightly better odds than a coin toss (60%) of getting a recommendation from the committee, but I wouldn't bet the farm on it.

The committee is also evaluating IDM Pharma's (NASDAQ:IDMI) experimental cancer drug Junovan, for the combination treatment of a type of bone cancer that occurs mostly in adolescents and young adults, and will report on whether it recommends it to the FDA on May 9. When Junovan is combined with other chemotherapy treatments, the probability of survival at six years is 77% for the drug versus 66% without it, which the company says is clinically meaningful because longer survival equates to a better chance of a cure. Given the company's very low float of around 10 million shares and the stock's recent upswing, an endorsement from the committee could bring further upside. However, it should be noted that the trial data IDM Pharma submitted differs from that published by the Children's Oncology Group (in a study supported by the National Cancer Institute). The company believes its data will be adequate, based on discussions with the FDA, and I would put the odds of an endorsement at about 60% because of the young patient population and Junovan's potential survival benefit.

Besides the recent FDA approval of its antibiotic eye drop AzaSite, InSite Vision (AMEX:ISV) has several likely positive catalysts coming up -- even if Inspire (NASDAQ:ISPH) passes up the timely opportunity to acquire its drug development partner. Near term, they include an international licensing deal for AzaSite with upfront cash plus royalties, a licensing deal for AzaSite Plus in which Inspire has priority, bullish analyst coverage as a result of increased attention for Inspire and AzaSite, and further development of AzaSite Otic using the company's recent cash infusion.       

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Fool contributor Mike Havrilla, R.Ph., B.S., Pharm.D., is a Rite Aid pharmacist who lives, writes,  works, and enjoys running on the streets and trails in the small Pennsylvania town of Portage. He invites your comments and feedback. Mike owns shares of InSite Vision but has no position in any other company mentioned in this article. The Fool has a disclosure policy.