Stocks On the Move: Inovio Pharmaceuticals Inc, Calithera Biosciences Inc, and Merus NV

U.S. stocks are down, as the Dow backs down from the 20,000 level. Among specific equities in focus today are biotech stocks Inovio Pharmaceuticals Inc (NASDAQ:INO), Calithera Biosciences Inc (NASDAQ:CALA), and Merus NV (NASDAQ:MRUS). Here's a quick look at what's moving INO, CALA, and MRUS.

• INO is up 4.8% at $7.26, after the biotech reported promising results from a Phase 1 study of its Zika vaccine. INO shares are still down 38% since their April highs, pressured lower by their 10-week and 20-week moving averages. Short sellers may be sweating today, with shorted shares accounting for 18.6% of INO's float. It would take traders 13.6 days to cover all of these shorted shares, at Inovio Pharmaceuticals Inc's average daily volume.
  
  
• CALA is up 18% at $3.60 -- one of the top performers on the Nasdaq today -- on news that the firm is joining forces with Bristol-Myers Squibb Co (NYSE:BMY) for a clinical trial collaboration of BMY's Opdivo and CALA's CB-839 in patients with clear cell renal cell carcinoma. Calithera Biosciences Inc shares have spent much of the past few months churning in the $3-$3.75 range, but hit a six-month high at their intraday peak.

• MRUS is also among the top performing Nasdaq stocks, up 47.3% at $20.84, after announcing a collaboration to develop antibody research programs with Incyte Corporation (NASDAQ:INCY). Merus NV shares are up 187% since bottoming out in late June, and the Wall Street freshman touched an all-time high of $22.19 earlier today. The stock is also enjoying a lift from some positive analyst attention, with Wedbush doubling its price target to $32 from $16.  MRUS short sellers are likely kicking rocks, with short interest up 17.5% over the last reporting period, and accounting for 9.8 times MRUS' average daily trading volume.