Immunomedics (IMMU) - Get Report shares are falling after the company's bladder-cancer-treatment candidate showed a response rate lower than that of a competitor's. 

In a presentation at the European Society for Medical Oncology meeting in Barcelona over the weekend, Immunomedics' sacituzumab govitecan showed a 29% response rate, short of the 44% response rate Seattle Genetics'  (SGEN) - Get Report competing drug showed. 

Analysts at Piper Jaffray, who have an overweight rating on Immunomedics, said both drugs are likely to be important bladder-cancer treatments, and they urged investors to wait for "more mature data" before deciding on the product.

Meantime, Piper Jaffray raised its price target on Seattle Genetics to $94 from $75 with an overweight rating. SVB Leerink raised its target on Seattle Genetics to $102 from $86 with an outperform rating. 

Shares of Immunomedics, Morris Plains, N.J., dropped 9% on the results. Seattle Genetics shares are rising 4.4%.