** Shares of drug developer Biohaven BHVN.N fall 1.6% to $29.92
** Brokerage Morgan Stanley cuts PT on BHVN to $63 from $69, after co's experimental bipolar disorder drug failed in a study
** Co on Monday said the drug, BHV-7000, did not show statistical improvement in symptoms of extreme mood swings in a mid-to-late stage trial when measured on a scale
** Brokerage now anticipates 2035 sales of $1.4 bln for the drug vs. $1.5 bln prior, which includes potential treatment for neurological diseases like different types of epilepsy and major depressive disorder
** Adds primary focus for the stock to remain on U.S. FDA's decision on brain disorder drug troriluzole this summer
** Brokerage maintains "overweight" rating; new PT is more than double upside to the stock's last close on Thursday
** BHVN has fallen 47.7% in the past 12 months
(Reporting by Siddhi Mahatole)
((siddhi.mahatole@thomsonreuters.com))