By Mike Yamamoto, managing editor of OptionMonsterNEW YORK -- Spectrum Pharmaceuticals ( SPPI) has lost a quarter of its value in the last three weeks, but now the bulls are back. OptionMonster's tracking systems detected the purchase of 3,500 November 16 calls for 45 cents at the same second in the final hour of trading Tuesday. This is clearly new buying, as open interest in the strike was only 749 contracts at the beginning of the day. The stock fell 3.24% to end the session at $12.23. The hematology and oncology drug developer gapped lower on Aug. 8 after reporting quarterly results even though it beat earnings and revenue forecasts. If Tuesday's long calls are held until they expire in mid-November, the stock would need to be above $16.45 at that time for the options to be profitable --a level seen just three weeks ago. Premiums on those contracts could also increase well before expiration if the shares rise by lesser margins, providing an opportunity to sell the calls with gains sooner. The trading pushed overall option volume in the name to nearly double its daily average. Calls outnumbered puts by 3 to 1, a reflection of the bullish sentiment. Yamamoto has no positions in SPPI.