Shares of Trevena Inc. TRVN exploded more than five-fold higher — up 420.6% — on very active trading Monday, after the Pennsylvania-based biopharmaceutical company said its China-based partner Jiangsu Nhwa received formal approval from China health regulators for the pain treatment Olinvyk. The stock, which had been halted 21 times for volatility since the open, has seen 75.7 million shares change hands, compared with the full-day average over the past 30 days of about 111,100 shares. Trevena said Olinvyk, which was approved by the U.S. Food and Drug Administration in August 2020, has been approved by China’s National…
