U.S. stocks rallied Friday, extending a string of sharp moves, amid upbeat economic news from the U.S. and rising hopes for more stimulus from global central banks.

The Dow Jones Industrial Average jumped 306 points, or 1.9%, to 16423, putting it on track for the biggest single-session gain this year. The S&P 500 gained 30 points, or 1.6%, to 1893 and the Nasdaq Composite Index rose 64 points, or 1.5%, to 4281. The strong gains came at the end of one of Wall Street’s most turbulent weeks in years, when investors fled risky assets and piled into the relative safety of U.S. government bonds. The wild trading has sent the price of bets meant to protect against market declines sharply higher this month.

Small cap Tetraphase Pharmaceuticals Inc. (NASDAQ:TTPH) jumps on a 3x surge in volume. Yesterday evening it announced the pricing of its public offering of 3.95M shares of common stock at $19.00 per share. Underwriters over-allotment is 592.5K shares. Closing date is October 22.

Investors slap Nano cap Repros Therapeutics Inc (NASDAQ:RPRX) on a 3x surge in volume after its announcement that the FDA has downgraded its November session with the company to a Type C guidance meeting from Type B pre-NDA meeting regarding Androxal (clomiphene citrate). The agency's action is based on its preliminary review of the firm's briefing document. It found that there is not sufficient clinical information for a Type B pre-NDA meeting. Repros believes the change of status is due to the absence of the one-year DEXA safety study and the Drug-Drug Interaction Study, both of which were unavailable at the time it submitted the briefing document to the regulator.

Horizon Pharma PLC (NASDAQ:HZNP) acquires the U.S. rights to Nuvo Research's (OTCPK:NRIFF) Pennsaid (diclofenac sodium topical solution) 2% for the treatment of pain due to osteoarthritis of the knee for a one-time payment of $45M in cash.Pennsaid 2% is a second generation version of Pennsaid 1.5%. Effective January 1, 2015 Pennsaid 1.5% will no longer be marketed in the U.S.

Theravance Inc. (NASDAQ:THRX) and collaboration partner GlaxoSmithKline's (GSK +1.7%) Anoro Ellipta (umeclidinium/vilanterol) improved lung function better in patients with chronic obstructive pulmonary disease (COPD) than Boehringer Ingelheim's Spiriva HandiHaler (tiotropium bromide).

Myriad Genetics (NASDAQ:MYGN) lowers its fiscal Q1 guidance due to an increase in costs and turnaround time for its myRisk Hereditary Cancer test. The test now accounts for 50% of its hereditary cancer samples. Its revised outlook is non-GAAP EPS of $0.25 (GAAP EPS: $0.21) on revenues of $168M.