UPDATE 2-Ariad Pharma says cancer drug shows promise

* Says initial results show anti-cancer activity * Says drug shows activity in drug-resistant patients

* Shares rise as much as 50 pct (Adds analyst comment, details, updates share movement)

July 27 (Reuters) - Ariad Pharmaceuticals Inc (ARIA.O) said preliminary results from an early-stage trial of an investigational compound has shown significant activity in patients with advanced blood cancers, who were resistant to other drugs, triggering a 50 percent rise in its shares.

Of the 23 chronic myeloid leukemia (CML) patients in the four highest dosing groups, 19 remain on study without disease progression, evidence of control of their disease, Ariad said.

All the patients have previously been treated with the currently available first- and second-generation targeted therapies for CML, the company said in a statement.

Merriman Curhan Ford analyst Joe Pantginis, who maintained his "neutral" rating on the stock, termed the AP24534 compound as a "long-term promise" in his research note.

In the trial, thirty-two patients have been enrolled to date of the about 50 patients the company expects to enroll, the company said in a statement.

CML is characterized by an excessive and unregulated production of white blood cells by the bone marrow due to a genetic abnormality.

Ariad shares were up 41 percent at $2.43 in afternoon trade. They touched a high of $2.60 earlier in the session and were one of the top percentage gainers on Nasdaq.

(Reporting by Shailesh Kuber in Bangalore; Editing by Gopakumar Warrier and Anil D'Silva)