Future directions
In the 10 years since Olson received CAR T-cell therapy, an entire industry has sprung up. Over 100 companies worldwide are now developing CAR T-cell therapies targeting various antigens. These therapies are directed at about 60 different tumor types, including solid tumors. Nearly 200 clinical trials are underway, though most are still in early stages: as of September 2019, only 5% had reached phase 3.
Clinical data show promising results for CAR T-cell therapy directed against CD22 (overexpressed on ALL cells), and BCMA (found on almost all multiple myeloma cells). Yet questions remain as to whether CAR T cells will be as effective if they target antigens other than CD19 or cells other than B lymphocytes. One of the biggest research questions is whether they will be effective against solid tumors.
One research avenue being watched with great interest is the development of universal CAR T cells. So far, such products are at very early stages of development (phase 1 trials), but they are attractive because of the potential advantages they offer over bespoke CAR T cells. Automating the process holds the promise of immediate availability, standardizing production, expanding access, and lowering costs. And because the T cells for this universal product come from healthy donors, they may function better than T cells that have been battered and bruised by past cancer treatments, or even the cancer itself.
However, precisely because they are developed from healthy donor T cells, universal CAR T cells may pose increased risk for GVHD. Scientists are trying to get around this problem by engineering universal CAR T cells that lack the T-cell receptor involved in GVHD.
There are also other concerns. Nature has a penchant for mutation. Engineering CAR T cells without T-cell receptors means the body may no longer detect or reject a universal CAR T cell if it goes rogue. Also, gene insertion in universal CAR-T therapy is targeted rather than random (as in bespoke CAR T cells), which could create off-target effects. Both issues create a theoretical risk of such products inducing an untreatable CAR T-cell therapy–associated cancer.
“The theoretic risk with universal cells is that their safety profile may not be as good for long term,” June commented.
Hope for the future
From that first trial in which June and Porter used CAR T cells, two of three patients they treated are still alive 10 years later.
Olson is one of these two, and he still undergoes monitoring every 3 months to check for relapse. So far, none of his tests have shown signs of his cancer returning.
After going into remission, Doug spent the next 6 to 9 months regaining his health and strength.
“I figured if I had this amazing treatment that saved my life, I had an obligation to stay alive,” he said. “I’d better not die of something like a heart attack!”
He took up long distance running and has completed six half marathons. He became involved in the Leukemia and Lymphoma Society, participating in fund-raising and helping newly diagnosed patients. Over the years, he has also given talks for researchers, people with cancer, and healthcare providers.
Doug is now 73. Today, he marvels at how rapidly the CAR-T field has progressed.
“Twenty years ago, if you had cancer, your prospects weren’t nearly as good as these days. In 2010, people still didn’t believe in CAR T-cell therapy,” he said. “My goal always in telling my story is a message of hope.”
This article first appeared on Medscape.com.