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CNBC's Huckman: FDA Warning on Rituxan

The deaths of two people from a rare brain infection has prompted the U.S. Food and Drug Administration to issue a warning on the drug Rituxan. CNBC's Mike Huckman was on "Squawk Box" with the details. Huckman said the deaths were caused by a rare brain infection (called PML) to patients with lupus--who were taking the drug to combat their disease.

Huckman said Rituxan is NOT approved for treating lupus but sometimes it's prescribed for the disease (lupus is a chronic autoimmune disease in which the immune system--and for unknown reasons--becomes hyperactive and attacks normal tissue). The drug is made by the pharma companies Ginentech and Biogen and has been on the market since 1997. It's primarily used to fight lymphoma and rheumatoid arthritis.

Huckman said Genentech issued a statement saying the company still plans to test Rituxan for treatment of lupus. The statement also said "While the contribution of Rituxan to the development of PML is unknown--it cannot be ruled out."

Huckman also related that two different biotech analysts--disagreed on whether Rituxan is safe to use. One analyst did say this warning could hurt Rituxan sales for fighting arthritis--and hurt Genentech's profits.