NEW YORK (TheStreet) -- Ionis Pharmaceuticals (IONS) - Get Report stock is falling by 5.08% to $20.27 in early-morning trading on Friday, as BMO Capital downgrades shares to "market perform" from "outperform" after GlaxoSmithKline (GSK) decided against initiating a phase-three study for the TTR-Rx drug the companies have been co-developing.

The firm slashed its price target to $26 from $55 on the stock.

BMO also lowered the probability of success for TTR-RX to 80% from 85% and volanesorsen commercialization to 65% from 85% given increased regulatory risk.

"We believe discovery of thrombocytopenia cases in the Phase III volanesorsenstudies further clouds the underlying cause of platelet reduction," the firm wrote in a note. "While we expect the volanesorsen trials to increase their platelet monitoring and remain onschedule, we believe the uncertainty increases the risk for FDA intervention."

Based in Carlsbad, CA, Ionis Pharmaceuticals  is engaged in discovering and developing ribonucleic acid-targeted (RNA-targeted) therapeutics.

Separately, TheStreet Ratings team rates the stock as a "sell" with a ratings score of D.

Ionis Pharmaceuticals's weaknesses include its feeble growth in its earnings per share, deteriorating net income, disappointing return on equity, weak operating cash flow and generally high debt management risk.

You can view the full analysis from the report here: IONS

TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this article's author.

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