Nektar Therapeutics Plunges on FDA Worries, Downgrade

Shares of Nektar Therapeutics

have plunged on Monday after the FDA raised concerns that a class of opioid constipation medications may cause heart problems. The company said that the FDA's heart-safety concerns could cast new risks and uncertainties over the development of its constipation medication known as naloxegol or NKTR-118. At last check Nektar shares had lost nearly 13 percent and were trading at $7.11. The stock has been falling since the morning and was sitting near new 52-week lows. The company also released top-line data from Phase III results of its opioid constipation drug which it is developing with AstraZeneca

. "Opioid-induced constipation is a burdensome condition which is often overlooked, inadequately managed and can negatively impact a patient's quality of life," said Martin Mackay, President of Research and Development, AstraZeneca. "The top-line results of the pivotal KODIAC studies provide important new information on the safety and efficacy of naloxegol as a potential treatment for opioid-induced constipation and we are looking forward to advancing this programme." The studies showed that "analysis of the data indicates that in KODIAC-04 both naloxegol doses (12.5 mg and 25 mg) demonstrated statistically significant results for the primary endpoint. P-values were 0.015 and 0.001 respectively." "In KODIAC-05, the 25 mg dose demonstrated a statistically significant result for the primary endpoint but the 12.5 mg dose did not. P-values were 0.202 for 12.5 mg and 0.021 for 25 mg." "The analyses also showed no clinically relevant imbalances in serious adverse events (SAEs), including externally adjudicated major cardiovascular events, across the three treatment arms in KODIAC-04, -05 and -07." Nektar shares are also reacting to a downgrade from Buy to Hold by Jefferies on Monday morning. The firm also lowered its price target on the stock from $10.00 to $8.00. The analysts wrote that "we are downgrading NKTR to Hold from Buy with a new $8.00 price target based on increased regulatory risks in OIC. Recent FDA scrutiny on CV risks with chronic-opioid antagonist use translates to higher approval hurdles potentially involving additional large CV outcome studies and potentially delaying naloxegol's approval/launch. Thus, NKTR is fairly valued on increased risks."