Aug 8 (Reuters) - The U.S. health regulator has approved

Citius Pharmaceuticals' ( CTXR ) blood cancer therapy, Lymphir,

for relapsed patients who have received at least one prior

treatment and asked for the addition of a boxed warning about

the risk of a rare blood condition, the company said on

Thursday.

Shares of the company fell 1.7% to 89 cents in premarket

trading.

The Food and Drug Administration had declined to approve the

therapy last year, seeking additional product testing data.

The prescribing information for Lymphir carries the

health regulator's serious "boxed warning", flagging a

life-threatening risk of a rare blood condition called capillary

leak syndrome.

Capillary leak syndrome causes blood plasma to escape

through tiny blood vessels and leads to a rapid drop in blood

pressure.

Lymphir, Citius' first approved treatment, is expected

to be launched within the next five months and is approved for

certain adult patients with relapsed cutaneous T-cell lymphoma,

a group of rare blood cancers that affects the skin.

The cancer has an incidence rate of 8.55 in 1 million people

in the United States, according to government data.

The FDA's approval is based on data from a late-stage trial,

which showed that 36.2% of patients treated with Lymphir showed

partial or complete response to the treatment while reducing

skin disease in 84% of patients in the study.

Citius acquired the licensing rights to Lymphir from India's

Dr. Reddy's Labs for an upfront payment of $40

million. Dr. Reddy's is also entitled to an additional $40

million in milestone payments related to U.S. approval of the

therapy.