Virtually every day there is a news headline touting another advancement in the treatment of cancer. It is often difficult to gauge which articles are reporting on small gains or minor variations on already common treatments, and which headlines mark the sort major milestones that mark future revolutions in cancer care.
Last week, the headlines reported on a major advance that, as an oncologist, got me truly excited.
We have previously known of examples in which the immune system can be altered to recognize a patient’s cancer as foreign and attack it, with remarkable results. For example, patients with melanoma or kidney cancer may be treated with a toxic hormone called IL-2 which activates their own immune cells in hopes that some might then turn against cancer cells. Other patients may receive a bone marrow transplant from another person in order to gain a whole new immune system in hopes of creating a “graft-versus-tumor” effect. When these therapies work, they can lead to dramatic and complete responses, even in patients with chemotherapy-resistant cancers. But these immune treatments are very non-specific, either rarely leading to immune cells that effectively fight cancer, or leading to major side effects from non-cancer fighting immune cells that damage the patient’s normal cells.
A new method for creating smarter immune cells was in the headlines last week. A patient’s own T-cells are removed, engineered to be active only against certain molecules that are on the surface of cancer cells, and re-infused to the patient. This approach has, in early studies, been shown to be safe and highly effective in the sorts of slow moving cancers (like chronic lymphocytic leukemia) for which the previous generation of immune therapies were also often successful.
The headline last week reported on the use of these new, targeted immune cells against a very aggressive and fast moving cancer, acute lymphoblastic leukemia. The treatment was very well tolerated, and the benefits were impressive, with five out of five patients with resistant leukemia having a rapid and complete remission.
New cancer therapies that are smart enough to attack cancer cells but also to spare non-cancer cells from damage are in many ways the “Holy Grail” of oncology. We have seen a revolution start with the addition of monoclonal antibodies, molecularly targeted drugs, and now new ways to engineer targeted T-cells. These are the headlines that someday may be tagged with “Nobel Prize…”