Roche's Rituxan successor first up in market scramble for first-line treatment of CLL

A number of drugmakers have been looking to get drugs across the finish line for approval of first-line use in the treatment of chronic lymphocytic leukemia (CLL), and Roche's ($RHHBY) Genentech and Biogen Idec ($BIIB) have gotten there first. The FDA today approved their drug Gazyva, a successor to Roche's Rituxan that it hopes will offset some of massive sales that drug generates when it finally succumbs to biosimilar competition.

Gazyva was approved for use in combination with chlorambucil for untreated CLL and is the first drug that the FDA has approved under its "Breakthrough Therapy" designation. CLL is the most common form of leukemia in adults, and the National Cancer Institute estimates there will be more than 15,680 new cases and more than 4,580 deaths in the U.S. this year, meaning it is a serious problem and a significant market. But competition may be coming up right behind. The FDA granted GlaxoSmithKline ($GSK) breakthrough designation for its drug Arzerra, which the company also hopes to get approved for first-line CLL use.

Arzerra, the leukemia drug that GSK shares with Genmab, provides a good idea of why a first-line treatment is so important to drugmakers. GSK picked up the drug in a $2.1 billion licensing deal with Genmab three years ago. It was approved in 2009 as a second-line treatment for CLL, but with that limited market, it was only able to eke out less than $100 million in revenue last year. GSK is also seeking first-line approval in the EU.

There have been other contenders. Celgene ($CELG) was conducting a study for the first-line use in CLL of its blockbuster Revlimid but called it off in July because there had been almost twice as many deaths in Revlimid patients as in control patients.

Of course, one of the drugs Roche's Gazyva will compete against is its own superdrug Rituxan. The Swiss drugmaker has mounted an effort to make Gazyva even better than Rituxan, a drug that is used for a wide variety of diseases, including leukemias, and which brought in $7 billion last year. The drugmaker this summer released data showing Gazyva outperforming Rituxan in the treatment of CLL.

- here's the FDA release
- see the Genentech release

Special Reports: 10 top drugs in biopharma's late-stage pipeline - Obinutuzumab/GA101, Roche and Biogen Idec | Top 10 experimental cancer drugs - 2013