April 6 (Reuters) - Bristol Myers Squibb said on Saturday data from late-stage studies of its experimental schizophrenia drug showed it helped reduce symptoms of the disorder without the common side effect of weight gain tied to other antipsychotics.

The drugmaker gained access to the treatment, called KarXT, through its $14 billion deal to buy Karuna Therapeutics last year. Long-term data of the drug reinforced the findings that were seen in previous short-term studies, the company said.

In a one-year follow-up, the drug helped curb symptoms such as delusions and reduced speech by more than or equal to 30%, as seen on a disease measurement scale, in over 75% of patients.

"Current antipsychotic treatments are associated with a number of adverse effects, including adverse metabolic profiles, increases in weight ... and there still remains a need for more effective treatments," said Roland Chen, SVP, global drug development for immunology, neuroscience and cardiovascular development at Bristol Myers.

The data showed KarXT reduced weight on average by 2.56 kilograms at 52 weeks. Majority of the participants, 65.1%, saw a reduction in weight over the course of the trial, with 17.6% of them having a decrease in body weight of more than or equal to 7%.

Across the trials, 14.9% of patients discontinued the study due to treatment-related adverse events. The most common adverse events were nausea and vomiting, the majority of which were mild and transient in nature, the company said.

KarXT is expected to drive sales through late-2020s and into the next decade, at a time when two of Bristol Myers' top drugs, blood cancer treatment Revlimid and blood thinner Eliquis face generic competition. (Reporting by Sneha S K in Bengaluru; Editing by Shilpi Majumdar)