Idelalisib

The medical journal Blood published three articles recently on Idelalisib, formerly known as CAL 101 and as GS-1101. One dealt with the remarkable success that Idelalisib has shown on CLL; another on the somewhat less successful attempts to treat MCL; and a third that was moderately successful in treating indolent NHL, including Follicular Lymphoma. The results come from a phase I clinical trial.

Idelalisib is a kinase inhibitor (as you know if you've been paying attention to these things). It specifically targets the P13 enzyme, which B cells need to survive. So inhibiting or blocking it will kill off the cancer cells.

The indolent NHL group involved 64 patients, all of whom had already had at least one previous treatment (and some as many as 10). Because this was a phase 1 trial, it could be considered a big experiment, with researchers asking first, will it work?, and second, is it safe? As such, patients were given 8 different variations on how many (it is taken as a pill) and how much of the treatment taken.

The results were decent: 47% had a response, with one achieving a complete response. The median duration of response was a little more than 18 months, and side effects were for the most part mild to moderate.

While 47% doesn't seem all that astounding, it's important to remember that this is a phase 1 study, and that's good enough to justify a phase 2, which will be more refined than the general phase 1 study. It will likely involve a specific number and strength for the dose, based on what worked best. In addition, according to the lead researcher, given the number of previous treatments that the patients had, the results were pretty remarkable.

So we have further evidence that Idelalisib might be a keeper.We're going to hear a lot more about this treatment over the next year, I think.