March 13 (Reuters) - The U.S. Food and Drug

Administration's staff reviewers on Wednesday raised safety

concerns over the use of Johnson & Johnson's ( JNJ ) and Bristol

Myers Squibb's ( BMY ) cancer therapies as earlier treatments

for blood cancer patients.

Staff reviewers said that the pattern of early deaths

observed in patients treated with both the therapies in their

respective trials raised uncertainty about the treatments'

overall survival benefit in patients.

The therapies - J&J's Carvykti and Bristol Myers' Abecma -

are approved by the FDA to treat patients with multiple myeloma

who have received at least four prior lines of treatment.

The FDA staff said that data for J&J's Carvykti was unclear

to establish a favorable benefit-risk profile of the treatment.

Data analysis provided by Bristol Myers did not provide

"convincing evidence" that treatment with Abecma helps patients

extend the time they live after receiving treatment or a benefit

of overall survival.

The comments were made in briefing documents prepared ahead

of a meeting of the FDA's independent advisers on Friday, which

is being closely watched by investors to understand the

regulator's view on CAR-T therapies after recent scrutiny into

the treatments.