Idelalisib for Indolent/Follicular Lymphoma

Back in September, Gilead applied for FDA approval for Idelalisib for indolent lymphomas (including Follicular Lymphoma) that had stopped responding to Rituxan and to alkylating chemotherapy (including CHOP and Bendamustine). They based the application on phase 2 clinical trial results (which is early).

A couple of weeks ago, the FDA granted Idelalisib "Breakthrough Therapy" designation, meaning it has the potential to be a major advance over anything that is currently available. This ain't no fourth-generation Rituxan wannabe. This is Pulp Fiction at the Cannes Film Festival -- something very new.

The results from that phase 2 trial were published in The New England Journal of Medicine a week ago. That's important, because it means they have been peer-reviewed, with experts in the field looking over the data and the methods for collecting it, and giving their approval.

The Background section of the article is pretty interesting (and more informative than other things I've read about Idelalisib:

Idelalisib  targets something called Pl3K, a lipid kinase that helps to regulate growth and death in cells. Pl3K comes in four different types, and is present in most cells. The fourth type, known as delta, is especially present in  blood cells. Idelalisibwas created to target this particular form of Pl3K, so it is ideal for use with indolent lymphomas. It's a kinase inhibitor, which means it stops Pl3K from doing its evil job of keeping cancer cells alive when they would otherwise die.

The study was fairly small -- 125 patients -- but pretty successful.  I'm not going to get too much into methods and results (you can read on your own, all you people with two healthy shoulders), but basically, 90% of the patients had their lymph nodes shrink. the overall response rate was 57%, including 6% who had a complete response. (Not sure what the difference is between that 90% with shrunken nodes and the smaller number who were classified as "responding.") For what it's worth, the 72 Follicular Lymphoma patients in the study had a 54% response rate, which wasn't the bast, but which was decent. Maybe more important was that "responses were rapid and durable" as patients kept taking the Idelalisib. Side effects were common, though they seem manageable, and doesn't overlap with other treatments, so some combinations might be in the future.

Overall, a bunch of good news in the last month for indolent lymphoma patients. The FDA review will take place later this year; let's hope it's fast and positive, and we have another arrow in the quiver soon.