NEW YORK (TheStreet) -- Keryx Biopharmaceuticals (KERX) shares are down -7% to $15.80 on Monday after being downgraded to "underperform" from "market perform" by analysts at FBR Capital  (FBRC) .

The firm also lowered its peak ferric citrate U.S. dialysis revenue estimate to $476M from $951M, while also lowering its price target to $14 from $16 after the company's ferric citrate treatment "Zerenex" was given a restrictive label by the FDA.

TheStreet has full coverage of the implications of the FDA's decision here.

STOCKS TO BUY: TheStreet Quant Ratings has identified a handful of stocks that can potentially TRIPLE in the next 12 months. Learn more.

KERX Chart KERX data by YCharts

EXCLUSIVE OFFER: See inside Jim Cramer's multi-million dollar charitable trust portfolio to see the stocks he and Stephanie Link think could be potentially HUGE winners. Click here to see the holdings for FREE.