Abexinostat is Fast Tracked for FL

The FDA has given Abexinostat a Fast Track designation for fourth-line treatment of Follicular Lymphoma.

Let's break that all down.

Abexinostat is an HDAC Inhibitor. Like all inhibitors, it works on cancer cells by stopping (or inhibiting) some process that's necessary for the cancer cell to grow and survive.

In this case, it inhibits HDAC, or Histone Deacatylase enzymes. These enzmyes are important for cell growth because they help arrange which parts of the cell control its growth. One of HDAC's jobs is to control the genes that allow cells to keep growing. By inhibiting HDAC, Abexinostat can help control cells that are otherwise out of control (and become cancer cells). There are other HDAC inhibitors being tested, but Abexinostat is different because it is given more frequently than others, and so can work on cancer cells continuously.

The trial that led to the designation is a phase 2 trial of 87 patients with a few different types of Lymphoma. The Overall response rate for the group was 28%, but for the smaller group of Follicular Lymphoma patients, the Response rate was 56%. Side effects were common, with 80% of patients in the trial having thrombocytopenia (low platelet counts), along with other nerve and blood count issues that often come with Lymphoma treatments.

The designation will be for fourth-line patients, which means, if it is approved, patients will need to have received three other treatments already.

The Fast Track designation by the FDA means the treatment will be handled a little differently than a regular FDA approval, like more frequent meetings with the FDA. It doesn't mean that the treatment will be approved faster, though the extra help from the FDA may move that along. Fast rack status is given to treatments that meet an unmet need, and that work on diseases that can become fatal without proper treatment.

I have to say, I'm not really excited about this one -- not yet, anyway. Fast Track status sounds like it should be really exciting, but it also signals that it's still pretty early in the process. The results we see are from a phase 2 study, which is always pretty small. But this is also a small group within a small study -- only 18 FL patients. And 56% percent is good, but it's also for Overall Responses, not Complete responses. And those side effects are not much of improvement over other treatments.

But it got FDA Fast track, so there must be some promise in it, right?

It's early. I try to keep my enthusiasm down for early studies. And if this goes to a larger phase 3 study, and there are even better results, then I'll start to break out a Happy Dance.

For now, we'll go with cautious optimism, and keeping an eye on this to see how it goes.