May 31 (Reuters) - Gilead Sciences' ( GILD ) Trodelvy

improved survival by 1.3 months more than chemotherapy in

previously treated patients with advanced lung cancer in a

late-stage trial, a difference that was not statistically

significant, the company said on Friday.

Patients given Trodelvy lived for a median of 11.1 months,

while those on chemotherapy lived for 9.8 months, Gilead said.

The company in January said that the non-small cell lung cancer

(NSCLC) trial had failed to meet its main goal of proving

Trodelvy could extend survival over chemotherapy.

The full results, presented at the annual American Society

of Clinical Oncology meeting in Chicago and published in the

Journal of Clinical Oncology, show that Trodelvy reduced the

risk of death by 16%, with similar improvement for

harder-to-treat squamous and non-squamous types of NSCLC.

Trodelvy, which belongs to a class of treatments known as

antibody drug conjugates, is currently approved in the U.S. for

patients with two specific types of advanced breast cancer and

bladder cancers.

Gilead said the 603-patient lung cancer trial showed a

survival improvement of 3.5 months for patients given Trodelvy

whose tumors had not responded to a last round of immunotherapy.

For patients whose lung cancer had responded to their last

immunotherapy, overall survival was a month longer for the

chemotherapy group.

"We think Trodelvy is a very active drug in lung cancer and

also quite tolerable," Bilal Piperdi, Gilead's vice president of

clinical oncology, said in an interview.

Serious side effects were reported by 67% of Trodelvy

patients and 76% of chemotherapy patients. The most common side

effects for Trodelvy were fatigue, diarrhea and hair loss.

Gilead is also studying Trodelvy in combination with Merck's ( MRK )

immunotherapy Keytruda as an initial treatment for NSCLC

patients.

Results for a small subset of patients in one of those

ongoing studies has shown they lived a median of 13.1 months

before their cancer worsened. That is an improvement over the

seven- to eight-month progression-free survival seen in

Keytruda trials, Piperdi said.