Dr David Porter Compares Use of CAR T-Cells for B-Cell and Solid Tumors

Chimeric antigen receptor (CAR) T-cells have been dramatically effective in treating B-cell cancers, according to David L. Porter, MD, of the University of Pennsylvania Health System. He also identified the use of CAR T-cells for treating solid tumors as a research area that will see more development in the coming years.

Transcript (slightly modified)

What cancer types have CAR-T cells been successfully used in? And are they being evaluated in solid tumors?

CAR T-cells have been most effective, and I would say in fact dramatically effective, in B-cell malignancies. The initial, really successful trials have targeted CD19. CD19 is a molecule that, while on normal B-cells, is on just about every B-cell malignancy. When you’re targeting something on cancer cells, part of the issue is to target something that is either specifically on cancer cells and not on normal tissue, or if it’s on normal tissue it should be on tissue that people can live without, in fact. And that is B-cells.

CAR T-cells, again CD19, have had unprecedented activity in B-cell ALL [acute lymphocytic leukemia], for instance. The initial trials are treating patients with multiply relapsed and refractory disease. Ninety percent of these patients go into remission, it really has been astounding. But they’ve also been effective for patients with B-cell CLL [chronic lymphocytic leukemia], with non-Hodgkin’s lymphoma. There’s emerging data now that they may be effective in multiple myeloma, which is another B-cell malignancy.

So this really has been the proof of concept, the proof of principle, and the best example that they can be effective in cancer therapy. Now that we know they can be effective, part of the issue is to try and expand this to treat other types of cancers. Other types of blood cancers like AML [acute myeloid leukemia] for instance, and there are clinical trials ongoing in that setting. And there have been a number of trials starting to use CAR T-cells in solid tumors.

We haven’t yet seen the same dramatic results in solid tumors that we have in B-cell malignancies, probably for a number of reasons. One issue is the ability to identify a target that is specifically on the cancer cell, but not on normal tissue, and that’s been much more difficult in some of these solid tumors than it is in B-cell malignancies.

But there’s a lot of energy and a lot of work going into try and identify unique targets to the cancer cell, so that you could target it without damaging normal tissue, and to test newer, more improved CAR T-cells for a number of solid malignancies. There are trials that have been done or are ongoing in certain kinds of lung cancer like mesothelioma. There are trials that have been done in ovarian cancer, and pancreatic cancer. And I think over the next few years, we’re going to start seeing much more development of CAR T-cells for these solid tumors.