UPDATE 1-Geron stem-cell therapy found safe in preclinical study

* Reports positive preclinical data in heart treatment

* Study shows treatment does not cause arrhythmias in animals

* Shares up 3 pct

May 13 (Reuters) - Geron Corp GERN.O said data from a preclinical study showed its experimental stem-cell product for the treatment of chronic heart injury did not cause any abnormal electrical activity after it was transplanted in the site of the injury.

The product, GRNCM1, was tested in guinea pigs with chronic cardiac injury, to assess whether transplantation increases the incidence of cardiac arrhythmia, a safety concern for cardiac cellular therapies.

Arrhythmia is an abnormality of the heart rhythm, which can cause the heart to pump less efficiently.

The company said the study showed that there was no significant difference in the incidence of either spontaneous or induced arrhythmias between those receiving GRNCM1 and a dummy treatment.

Geron is currently conducting studies in a swine model of heart attack to further test the preclinical safety and efficacy of the product.

Shares of the company were trading up about 1 percent at $5.79 Thursday afternoon on Nasdaq. They touched a high of $5.91 earlier in the day. (Reporting by Krishnakali Sengupta in Bangalore; Editing by Unnikrishnan Nair)