(Adds comment by regulator, analyst forecast, background, stock prices)
Feb 12 (Reuters) - U.S. health regulators on Wednesday approved the Johnson & Johnson and Pharmacyclics Inc cancer drug Imbruvica to treat chronic lymphocytic leukemia, a slowly progressing form of blood cancer.
The Food and Drug Administration decision marks the second approval recently for the oral medicine, known chemically as ibrutinib. In November, the drug won U.S. approval to treat a rare and aggressive form of non-Hodgkin lymphoma called mantle cell lymphoma in patients who have received prior treatment with at least one other therapy.
The latest approval is also for so-called second line therapy after at least one prior treatment fails or stops working, the FDA said.
"Today's approval provides an important new treatment option for CLL patients whose cancer has progressed despite having undergone previous therapy," Richard Pazdur, head of the FDA's Office of Hematology and Oncology Products, said in a statement.
"The FDA completed its review of Imbruvica's new indication under the agency's accelerated approval process, which played a vital role in rapidly making this new therapy available to those who need it most," Pazdur said.
About 15,680 Americans were diagnosed with CLL and 4,580 died from the disease in 2013, according to the National Cancer Institute.
There had been some disappointment in the market when the original approval of the drug did not include both types of cancer. The second approval provided a jolt for Pharmacyclics shares, which were up 6.7 percent at $141.75 on the Nasdaq on Wednesday afternoon.
RBC Capital Markets analyst Michael Yee has been forecasting long-term annual worldwide sales of $5 billion for Imbruvica.
According to long-term follow-up data from a midstage clinical trial presented at a major medical meeting in December, the drug maintained its effectiveness in keeping the disease at bay for most patients.
With a median follow-up of more than 27 months of treatment, nearly all of the previously untreated patients and almost three-quarters of the relapsed patients in the study had no evidence of their CLL progressing.
"Patients receiving ibrutinib are doing much better than historically what we're used to seeing with CLL," Dr John Byrd, a co-leader of that study, told Reuters at the time.
While Pharmacyclics shares were up sharply, shares of the far larger J&J were off 0.5 percent at $92.51 on the New York Stock Exchange (Reporting by Bill Berkrot in New York; editing by Andre Grenon and Matthew Lewis)
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