Shares of Insmed ( INSM) were among the best-performing health-related stocks Tuesday, climbing 17% after the company's drug Iplex received Food and Drug Administration approval. The drug, which is used to treat growth failure in children who are missing a certain growth hormone, was granted orphan drug status, which means the company can market the drug on an exclusive basis for seven years. "We are very pleased Iplex was approved, making Iplex the only approved once-daily IGF-1 replacement therapy available to treat children with severe short stature," the company said. Shares of Tercica ( TRCA), which has a competing drug that's also been awarded orphan drug status, sank on Insmed's FDA approval news. Earlier this month, Tercica filed a lawsuit against Insmed, alleging that Insmed engaged in deceptive promotional statements and unfair business practices related to Tercica's competing Increlex product. Insmed said the complaint "is unwarranted and without merit." Shares of Insmed were recently trading up 26 cents to $1.75, while shares of Tercica tumbled $3.31, or 33%, to $6.59. FoxHollow Technologies ( FOXH) tumbled 15% after the medical device company announced the resignation of its chief executive officer. Robert Thomas, 44, will retire from the company on Jan. 1. John Simpson, founder and chairman, will serve as Thomas' replacement until the company names a new CEO. Thomas, who joined FoxHollow in 1998, will serve as a consultant to the company. FoxHollow also said that it continues to expect fourth-quarter sales of $40 million to $42 million and full-year sales of $126 million to $128 million. Analysts polled by Thomson First Call project higher fourth-quarter sales of $43.4 million and 2005 sales of $129.4 million. Shares were trading down $7.11 to $39.01. Shares of Vertex Pharmaceuticals ( VRTX) rose 3% after the company signed a new agreement with GlaxoSmithKline ( GSK) to develop and commercialize VX-409, a subtype selective sodium channel modulator that's used for pain treatment. GlaxoSmithKline will have the exclusive right to develop and commercialize VX-409. Vertex will receive an upfront payment of $20 million and could receive up to an additional $385 million if certain milestones are reached. GlaxoSmithKline will also pay Vertex royalties that are tied to annual sales. Vertex shares were trading up 75 cents to $27.