Shares of Erytech Pharma SA /zigman2/quotes/203877157/composite ERYP +2.21% rocketed 98.5% on heavy volume in premarket trading Friday, enough to make them the biggest gainer and most actively traded ahead of the open, after the France-based biopharmaceutical company said it's treatment for hypersensitive acute lymphocytic leukemia (ALL) patients was granted Fast Track designation by the Food and Drug Administration. Trading volume was 11.5 million shares in recent trading, compared with the full-day average of about 66,600 shares. "This is yet another significant milestone and meaningful inflection point in advancing our lead product candidate eryaspase, further supporting our recently announced intention to submit a [Biologics License Application] for eryaspase in hypersensitive ALL patients," said Chief Executive Gil Beyen. "We believe that the FDA's Fast Track designation for eryaspase underscores its potential to address this high unmet medical need." The stock, which closed Thursday at a 16-month low, has tumbled 42.8% over the past three months through Thursday, while the iShares Biotechnology ETF /zigman2/quotes/206189322/composite IBB -1.75% has gained 7.2% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.28% has tacked on 5.7%.