After-hours buzz: Valeant, Chesapeake, Medivation & more

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Scott Mlyn | CNBC

Check out the companies making headlines after the bell Tuesday:

U.S.-listed shares of Valeant Pharmaceuticals slid in extended trading after the company received a notice of default from holders of some of its bonds.

Valeant has been the subject of widespread scrutiny after high-profile investigations of its pricing and accounting practices.

Chesapeake Energy shares pared some of the day's gains after hours. The stock had closed up 34 percent Tuesday, building on the prior day's gains, after the natural gas producer maintained its borrowing limit at $4 billion, at a time when many oil and gas producers are preparing for large cuts to their credit lines. Analysts upgraded the stock on the news.

Medivation's stock rallied after hours after reports that it fought back a takeover from rival Sanofi. Sanofi sought to expand its cancer-treatment business, according to Bloomberg reports, by acquiring Medivation, which makes a prostate-cancer treatment called Xtandi. Sanofi has been the subject of a highly-publicized whistleblower case over alleged corporate kickbacks.

Shares of Foot Locker bounced after competitor Under Armour was downgraded by analysts Monday. Defending Masters champion Jordan Spieth, an Under Armour shoe spokesperson, failed to defend his title Sunday.

JetBlue's shares popped after it reported a 12.1 percent year-over-year traffic increase in March. Earlier in the day, the airline announced an expansion of Mint, a high-end personalized service for premium travel.

— CNBC's Christine Wang and Fred Imbert contributed to this report.