What's better than momentum? Mo' momentum.

Let's take a closer look at five of this past week's biggest scorchers.


May 11 Weekly Gain My Watchlist
Arena Pharmaceuticals (Nasdaq: ARNA) $6.36 146% Add
Vertex Pharmaceuticals (Nasdaq: VRTX) $62.02 66% Add
Rosetta Stone (NYSE: RST) $13.64 29% Add
Accretive Health (NYSE: AH) $10.86 27% Add
Achillion Pharmaceuticals (Nasdaq: ACHN) $7.20 20% Add

Source: Barron's.

Arena Pharmaceuticals was last week's biggest winner, soaring 146% after an advisory committee showed support for its lorcaserin weight-loss treatment. Several obesity drugs are battling it out for regulatory approval, and the stocks themselves will pack on the pounds or shed them as the victors emerge.

The market's second biggest gainer was another biotech. Vertex rose in a sluggish market after releasing promising clinical data for its VX-809 and Kalydeco drugs in the treatment of cystic fibrosis.

Rosetta Stone investors know that applause doesn't need a translation. The language learning program company posted stronger-than-expected quarterly results. Revenue soared above estimates, and Rosetta Stone posted a much smaller deficit than what Wall Street was targeting.

Accretive Health may have slashed its outlook, but analysts preferred to focus on the health care services provider's ability to surpass market expectations in its latest quarter.

Finally we have Achillion moving higher after reporting a narrowing quarterly deficit, offering up encouraging development news, and snagging a UBS analyst upgrade.

More winners for you
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