FRANKFURT, Sept 11 (Reuters) - Roche said on

Wednesday the promising results of an early-stage trial of its

experimental weight-loss pill that bolstered its shares in July

were based on just six patients, underscoring the uncertainty of

the development project.

The Swiss drugmaker said in July that the once-daily pill

CT-996 resulted in a placebo-adjusted average weight loss of

6.1% within four weeks in obese patients without diabetes in a

Phase I trial.

Presentation slides published on Wednesday showed that while

the trial involved 25 participants overall - six of which were

given an ineffective placebo for comparison - the result summary

was taken from the best-performing of the three other subgroups

on the experimental treatment.

The second-best-performing subgroup, which had seven

volunteers, reached an average placebo-adjusted weight loss of

4.6%, the data showed.

The company reiterated that larger trials in the second of

three development stages would start next year.