The top pre-market NASDAQ Stock Market gainers are: American Dental Partners, NPS Pharmaceuticals, Tekelec, Pharmasset, and DragonWave. The top pre-market NASDAQ Stock Market losers are: OmniVision Technologies, Vertex Pharmaceuticals, ARM Holdings, Logitech International, and Siliconware Precision Industries.

Gainers

American Dental Partners, Inc. (ADPI) stock jumped 79.67 percent to $18.65 in the pre-market trading. The company said it agreed to be acquired by funds affiliated with private equity investment firm JLL Partners, Inc. for $19 per share in cash. The deal is valued at about $398 million, including $81 million in currently outstanding debt. In the takeover deal, the price represents a premium of 83 percent to the closing price of the common shares as of Nov. 4. The transaction is now expected to close during the first quarter of 2012. The company noted that a special committee of its board of directors, composed of six independent directors, negotiated the deal and recommended it to the full board. It is expected that Gregory Serrao, the company's Chief Executive Officer, and other members of senior management will continue in their roles after the completion of the transaction.

Separately, American Dental Partners reported third quarter earnings of $2.68 million or $0.17 per share, compared to $2.72 million or $0.17 per share last year. Adjusted earnings were $4.28 million or $0.27 per share, compared to $4.34 million or $0.27 per share last year. Revenue declined to $70.24 million from $71.12 million. Analysts had expected profit of $0.23 per share on revenue of $72.10 million.

NPS Pharmaceuticals, Inc. (NPSP) stock soared 11.41 percent to $6.25 in the pre-market trading. The company announced positive top-line results from REPLACE, a Phase 3 registration study of NPSP558, the company's bioengineered replica of human parathyroid hormone or rhPTH 1-84, in adult hypoparathyroidism patients. The company said the symptoms of hypoparathyroidism are typically managed with large doses of oral calcium supplementation and active vitamin D therapy to reduce the severity of symptoms. The prolonged use of oral calcium supplementation and active vitamin D therapy may result in serious long-term health complications. In an intent-to-treat analysis, 53 percent of NPSP558-treated patients achieved the primary endpoint versus 2 percent of placebo-treated patients (p<0.0001).

The primary efficacy endpoint was defined as a 50 percent or greater reduction in oral calcium supplementation and active vitamin D therapy and a total serum calcium concentration that was normalized or maintained compared to baseline after 24 weeks of treatment. REPLACE was a 28-week, double-blind, placebo-controlled study. At week 24, 43 percent of patients treated with NPSP558 were able to achieve independence from active vitamin D therapy and a calcium supplementation dose of 500 mg/day or less, as compared to five percent for patients treated with placebo (p<0.0001). The company said the REPLACE study showed that NPSP558 was well-tolerated. Thirteen of the 134 randomized subjects discontinued the study early, of which seven were placebo-treated and six were NPSP558-treated. Overall, the incidence of adverse events and serious adverse event were similar among both groups.

Tekelec (TKLC) stock climbed 10.61 percent to $10.95 in the pre-market trading. The company said it agreed to be taken private by a consortium led by Siris Capital Group, LLC for $11.00 per share in an all-cash deal valued at about $780 million. The company's board has unanimously approved the deal and has recommended its shareholders also to approve it. The deal, which is primarily subject to shareholder approval, is expected to close during the first quarter of 2012. The buying consortium has secured committed financing, consisting of a combination of equity and debt financing. Following the closure of the deal, Tekelec's management team is expected to remain in place, with Merle Gilmore, former President of Motorola's Communications Enterprise and Chairman of the Board of Airvana Network Solutions Inc., will take over as Tekelec's Executive Chairman.

Separately, Tekelec reported third quarter earnings of $0.76 million or $0.01 per share, compared to a loss of $0.13 million or break-even per share last year. Adjusted earnings were $13.05 million or $0.19 per share, up from $10.17 million or $0.15 per share last year. Revenue declined 2 percent to $106.18 million. Analysts had expected profit of $0.18 per share on revenue of $104.27 million. Looking ahead into the fiscal 2011, the company increased its earnings guidance to range of $0.36 to $0.43 per share from previous forecast of $0.22 to $0.32 per share. The company also raised its revenue outlook to range of $395 million to $410 million from previous range of $360 million to $400 million. Street analysts predict profit of $0.41 per share on revenue of $398.58 million.

Pharmasset, Inc. (VRUS) stock grew 8.39 percent to $74.67 in the pre-market trading.

DragonWave Inc. (DRWI) stock gained 3.73 percent to $5.28 in the pre-market trading. The company said it agreed to buy the microwave transport business from Nokia Siemens Networks in a cash and stock transaction. Further, the company may also become a preferred supplier of packet microwave and related products to Nokia Siemens Networks. The consideration to be paid upon the transaction's closing, anticipated in first-quarter 2012, comprises 10 million euros in cash and DragonWave stock worth another 5 million euros. Also, about 360 employees may be transferred to DragonWave as part of the deal.

Losers

OmniVision Technologies Inc. (OVTI) stock fell 17.39 percent to $14.30 in the pre-market trading. The company said it lowered its second quarter revenue outlook to range of $212 million to $217 million from previous forecast of $255 million to $275 million, while Street predicts $260.41 million. The company said it reduced revenue guidance due to a cutback in orders for certain key projects. The company also said its board has authorized a share buyback program, allowing the repurchase of up to $100 million of its stock. The program is effective immediately, but no end date has been provided. OmniVision's second-quarter results are expected on Nov. 29.

Vertex Pharmaceuticals Inc. (VRTX) stock declined 4.53 percent to $34.97 in the pre-market trading. The company announced the final results from a Phase 2a study of the investigational selective oral JAK3 inhibitor VX-509. The data showed substantial and statistically significant improvements in multiple measurements of rheumatoid arthritis activity. The 12-week study met its two primary endpoints, defined as a statistically significant improvement in the proportion of people who achieved at least a 20 percent improvement in the signs and symptoms of RA and a statistically significant improvement from baseline in Disease Activity Score 28. The data from the study will be presented in a poster session on November 8 at the 2011 Annual Meeting for the American College of Rheumatology in Chicago. Based on the Phase 2a data to be presented at ACR, a six-month Phase 2b study of VX-509 in RA is expected in early 2012.

Separately, the company reported encouraging interim results from an ongoing phase-II study designed to evaluate the safety and tolerability of Incivek, or telaprevir tablets, in combination with pegylated-interferon and ribavirin in people who are co-infected with chronic genotype-1 hepatitis C and human immunodeficiency virus, or HIV. Part 'A' of the study involved evaluation of people who are not currently being treated with antiretroviral therapy for HIV infection, while part 'B' involved evaluation of those who are taking an Atripla or Reyataz-based regimen for HIV. The primary endpoint of the randomized, double-blind, placebo-controlled, parallel group, multi-center study is to evaluate the safety and tolerability of telaprevir-based combination therapy in people co-infected with hepatitis C and HIV. The secondary endpoint is to evaluate rates of sustained viral response, or cure.

ARM Holdings plc (ARMH) stock decreased 2.69 percent to $30.37 in the pre-market trading.

Logitech International SA (LOGI) stock declined 1.53 percent to $9 in the pre-market trading.

Siliconware Precision Industries Co. Ltd. (SPIL) stock moved down 0.87 percent to $5.0062 in the pre-market trading.