INDIANAPOLIS (AP) — Eli Lilly & Co. said Sunday it will continue developing a potential schizophrenia treatment and considered recent midstage study results "inconclusive" after the drug candidate was no more effective than placebo. The company said it considers the midstage, or Phase II, study results inconclusive because of the unusually high response rate from patients taking placebo. It saw more than double the response in those patients than is historically seen in such studies. The drug developer said "inconclusive" study results are common in the field of neuroscience. The results were presented at the 12th International Congress on Schizophrenia Research in San Diego. In all, 669 patients enrolled and 393 completed the study. None of the four doses of mGlu2/3 were more effective than placebo and three patients taking the drug suffered from convulsions. Other than the convulsions, the company said the drug was well-tolerated. Eli Lilly also said the already approved anti-psychotic Zyprexa was no more effective than placebo when given in 15-milligram doses, once-daily. Zyprexa has previously proved more effective than placebo. The company plans to start another midstage clinical trial on mGlu2/3. Leerink Swann analyst Seamus Fernandez called the results a "serious blow" to Eli Lilly's pipeline. "We believe any additional studies (with the drug candidate) should be viewed as exploring the mGlu2/3 mechanism, but the agent should not move forward into Phase III studies due to safety concerns," he said, in a note to investors. Fernandez said consultants familiar with the drug's development have said it now demonstrated either convulsions or seizures in two species, including humans.