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Volatility is returning to the stock market, and investors felt the downward side of that equation on Monday. Major market benchmarks fell as much as 1% as investors tried to prepare for the first U.S. Presidential debate tonight. Although few market participants anticipate any major surprises from the debate from a policy standpoint, the perceived results of the debate could prompt changes in projections on the election's likely outcome, in terms of both who is in the White House and which party controls Congress. Even though the market fell, several stocks had good news that prompted impressive share-price gains. Among them were Array BioPharma (ARRY), Chemtura (NYSE: CHMT), and GW Pharmaceuticals (GWPH).

Array gets things in line

Array BioPharma soared 82% after the cancer-drug specialist announced favorable results in the first part of its phase 3 trial involving its binimetinib and encorafenib candidate treatments. Together with partner Pierre Fabre, Array said that the study met its primary endpoint of showing that the two drugs in combination significantly improved progression free survival in melanoma patients compared to using a single rival melanoma treatment. The median progression-free survival of 14.9 months was more than half again the 9.6 months, but just barely missed statistical significance, and reported adverse events suggested that the combination was well-tolerated among patients. Going forward, investors are hopeful about the prospects for Array after Part 2 results come out next year.

Chemtura gets an offer it can't refuse

Chemtura rocketed 16% higher in the wake of receiving a buyout offer from Lanxess. The $2.7 billion buyout from the German company will pay Chemtura shareholders $33.50 per share in cash, helping CEO Craig Rogerson and his management team make good on their commitment to deliver what Rogerson called "a transformative opportunity to create value for our shareholders." Lanxess believes that the buyout will help it create a much larger player in the global additives business, and Chemtura's urethane and organometallics businesses will help Lanxess round out its overall portfolio. Consolidation in the specialty chemicals business has accelerated lately, and most investors seem pleased that the deal is apparently moving forward.

GW Pharma gets more good news

Finally, GW Pharmaceuticals climbed 17%. The company said that its Epidiolex candidate treatment for epilepsy produced positive results from a second phase 3 clinical trial. The study found that patients taking various doses of the drug saw a 37% to 42% median reduction in the number of drop seizures per month, following up on previous encouraging results from phase 3 trials of the drug. Childhood-onset epilepsy has been extremely difficult to treat, and researchers are optimistic that Epidiolex could be a substantial step forward in treating the disease. Analysts responded with upgrades of the stock, helping to send GW Pharma up further.