Shares of navigation devices maker Garmin ( GRMN) fell after a rival warned of lower first-quarter revenues. Shares of Garmin were down $4.23, or 8%, to $48.47 after its competitor TomTom said first-quarter revenue would be lower than its earlier forecast following price cuts leading up to the introduction of new models, as well as the reduction of inventory by retailers in Europe. Meanwhile, Repligen ( RGEN) said Tuesday that it settled its patent infringement suit -- dating back to January 2006 -- with Bristol-Myers Squibb ( BMY) regarding rheumatoid arthritis treatment Orencia. The news gave Repligen's shares a 79-cent, or 14%, bump to $6.23. Shares of weight management and fitness program provider NutriSystem ( NTRI) jumped 24.4% to $18.59. The Horsham, Pa.-based company announced that president and COO Joseph Redling will replace CEO Michael Hagan effective May 1. Hagan will continue to serve as nonexecutive chairman. NutriSystem also forecast first-quarter revenue of about $216 million, ahead of the Thomson Financial consensus estimate of $203.5 million. Boenning & Scattergood upgraded the stock to market perform from market underperform. Metro PCS ( PCS) added $1.11, or 5.9%, to $20.00 after the company said it added approximately 960,000 gross new subscribers, representing a 15% increase over the first quarter of 2007. The stock was also upgraded to outperform from market perform by an analyst at Wachovia. And elsewhere, Antigenics ( AGEN) rose 56 cents, or 22.7% to $3.03, after it said Tuesday that its Oncophage, a treatment for kidney cancer patients, won its first approval in Russia in patients with intermediate risk of cancer relapse. The company said it will launch in Russia in the second half of 2008 and will seek conditional approval in Europe later this year. Oncophage is derived from each individual's tumor, and contains what the company calls the "antigenic fingerprint" of the patient's particular cancer. Thus, it's designed to reprogram the body's immune system to target only cancer cells bearing this fingerprint, according to the company. On the losing side, Agria ( GRO), a Beijing seller of upstream agricultural products for China, announced this morning that business was not disrupted by the resignation of COO Zhixin (Frank) Xue. The resignation was announced yesterday after the close. Shareholders remained skeptical, selling the company down 39.9% to $5.29.