Updated from 11:24 a.m. ESTNearly a dozen patient deaths have been recorded in an ongoing clinical trial of Celgene's ( CELG) experimental drug Revlimid, TheStreet.com has learned. If confirmed and attributable to the drug, the deaths could delay, or derail, Revlimid's chances for U.S. approval, which would force investors and analysts to reduce forecasts for the company's near-term earnings and sales growth. Dr. Alan List of the H. Lee Moffitt Cancer Center in Tampa, Fla., and the lead investigator in Celgene's Revlimid MDS study, confirmed there were patient deaths. But he would not disclose a precise number because he is bound to a Celgene confidentiality agreement. List is a paid consultant to Celgene. "There were some deaths in the study but very few were treatment related," says List. "Remember, we have a patient enrolled in this study who is 96, and the median age of patients is in the 70s, so the expectation for survival for one year is not high." The clinical trial in which the deaths occurred is testing Revlimid as a treatment for patients with a low-grade, low-risk form of myelodysplastic syndrome, or MDS, a cancer-like bone marrow disease. Celgene shares fell on the news. They were recently down $1.67, or 5.7%, to $27.69 on eight times normal volume. The stock hit a three-year high of $32.58 on Nov. 11, adjusted for a 2-for-1 stock split in October. There are 148 patients enrolled in the Revlimid study, which would put the death rate at just over 7% if the reports of 11 deaths are accurate. Celgene's chief spokesman Brian Gill, asked to confirm or deny the patient deaths in the Revlimid study, said, "I, Brian Gill, am not aware of any deaths. I'm not saying there are or aren't any deaths." Gill declined to offer a formal Celgene response. Gill added that a data safety monitoring board is charged with overseeing the safety of this Revlimid study in MDS patients. All serious adverse events, including patient deaths, in the study are supposed to be reported to the safety board, which is then charged with determining whether or not these adverse events are related to Revlimid. "If the data safety monitoring board finds a correlation between deaths and the drug, then the study would be stopped," said Gill, adding that none of the ongoing Revlimid studies have been stopped.