U.S. stocks rallied on Tuesday, with the S&P 500 on track for a fourth straight session of gains boosted by strong corporate results, including Apple's.

The S&P 500 and Dow Jones were up more than 1 percent while the Nasdaq rose more than 2 percent, boosted by better-than-expected results from several major tech companies. The largest percentage gainer and decliner on the S&P 500 were both related to earnings. The largest gainer was Waters Corp, which rose 8.8 percent, while the largest decliner was Chipotle, down 6.1 percent.

Thinly-traded nano cap MELA Sciences Inc(NASDAQ:MELA) rises on a 4x surge in volume albeit on turnover of only 135K shares.Yesterday, the SEC declared its S-3 effective. It issued its prospectus today for the sale of up to 21,637,429 shares of common stock by selling stockholders. The July 21, 2014 securities purchase agreement included warrants to purchase up to 10,643,276 shares of common stock at $2.45. This is the only potential source of new capital available to the company. MELA currently exchanges hands for ~$2.21.

At the American College of Gastroenterology Annual Scientific Meeting, Synergy Pharmaceuticals Inc(NASDAQ:SGYP)presented data from a 423-patient Phase 2b dose-ranging study assessing the safety and efficacy of plecanatide in patients with irritable bowel syndrome with constipation (IBS-C).Patients taking 3.0 mg and 9.0 mg plecanatide showed statistically significant improvement in Overall Responder rate (41.9% and 40%, respectively vs. 24.7% for placebo), a secondary analysis in the study and the endpoint required for FDA approval for the IBS-C indication.

Thinly-traded micro cap Omeros (NASDAQ:OMER) is down 14% premarket on light volume in response to its announcement that it has suspended its Phase 2 clinical trial evaluating the safety and efficacy of its phosphodiesterase 10 inhibitor, OMS824, as a treatment for patients with Huntington's disease.

The Dermatologic and Ophthalmic Drugs Advisory Committee votes unanimously in favor of approving Novartis' (NYSE:NVS)interleukin-17A inhibitor secukinumab for the treatment of adult patients with moderate-to-severe plaque psoriasis who are candidates for systemic therapy.  A final decision by the FDA is expected in early 2015.

Comfortable that the product candidate's development is in good hands, Enanta Pharmaceuticals Inc(NASDAQ:ENTA)declines to exercise its co-development option with AbbVie (ABBV +1.9%) for ABT-493, Enanta's next-generation protease inhibitor for hepatitis C. It will be eligible for certain regulatory approval milestones as well as royalties on net sales.