The Blood Cancer Journal recently published the results of a phase I clinical study on Ixazomib, a proteasome inhibitor. It showed some promise for use on Follicular Lymphoma.
The article compares Ixazomib to Bortezomib (also known as Velcade), which was the first proteasome inhibitor to get approval. (It was approved for Mantle Cell Lymphoma, though some clinical trials for Follicular Lymphoma have looked good.) Bortezomib/Velcade works by blocking proteasomes, which help keeps cells healthy by getting rid of older and messed-up proteins. Protease inhibitors block that process in cancer cells, so all of those messed up proteins pile up in the cell and cause it to die.
Ixazomib will work in a similar way, though it has a different structure than Bortezomib/Velcade, which the developers hope will result in greater effectiveness and fewer side effects.
The phase I trial was meant to test whether or not it would work on certain types of lymphomas, to measure side effects, and to determine what the ideal dose would be. Of the 26 patients who went through the trial, 11 had Follicular Lymphoma, and 4 of them had a response. This is good enough to move on to a phase II trial.
The usual warnings apply here:
Phase I is very early. There will be a lot of time between now and when (and if) this gets approval, and clinical trial volunteers will be needed. It will also face the hurdle of needing to show it is better than what we have now, with Velcade. A response from 4 out of 11 FL patients is good, though not overwhelmingly good. We've seen a few monoclonal antibodies try to outperform Rituxan, and so far no one has hit on the magic formula that will do that. Will the same thing happen with some of these attempts to improve various inhibitors?
We shall see.