The Food and Drug Administration (FDA) is on the verge of approving the first-ever gene therapy treatment for use in the United States.
If it goes through as expected, the therapy will be used to treat children and young adults with advanced acute lymphoblastic leukemia (ALL).
The FDA's Oncologic Drugs Advisory Committee earlier this month recommended that the agency approve Novartis’ experimental chimeric antigen receptor (CAR-T) therapy, CTL019 (tisagenlecleucel).
It’s an individualized therapy in which a person’s T cells are removed from their blood and reengineered to fight cancer. Then they’re infused back into the patient.
That’s why it’s called a “living drug.”
In a recent clinical trial, 83 percent of patients experienced complete remission or complete remission with incomplete blood count recovery within three months.
The FDA is expected to make a decision in September. The agency usually follows its committee’s recommendations.
A new era in cancer treatment
Experts are optimistic about the potential of CAR-T.
Dr. Santosh Kesari is a neuro-oncologist and chair of the Department of Translational Neuro-oncology and Neurotherapeutics at the John Wayne Cancer Institute at Providence Saint John's Health Center in California.
Kesari told Healthline that if approved, the therapy will be a revolutionary breakthrough in cancer treatment.
“It will be the first application of this type — combining gene therapy and immune therapy to modify a patient’s own cells to go attack cancer cells,” he said.
Kesari explained that this application could work in other cancers where there’s a specific target.
He pointed to a City of Hope case study involving a 50-year-old man with recurrent multifocal glioblastoma, a type of brain cancer.
The treatment was part of a phase I clinical trial to test the safety of CAR-T therapy when delivered directly to brain tumors. A successful response was sustained for more than seven months, longer than would usually be expected.
“So, there is potential for application in solid tumors if we identify the right marker, making sure we manage side effects,” said Kesari.
In an email interview with Healthline, Dr. Swati Sikaria, medical oncologist from Torrance Memorial Medical Center in California, explained that the goal is to choose a target as unique to the cancer as possible while avoiding damage to the noncancerous cells of the body.
“This initial success paves the way for creating CAR-T cells with targets for other malignancies,” she explained.
“Whether the success in ALL can be replicated in other types of cancers, I’m cautiously optimistic. We’ll have to see what ongoing and future clinical trials show. The most notable progress has been in multiple myeloma as well as glioblastoma, the type of tumor Senator [John] McCain was recently diagnosed with,” said Sikaria.
In a review article published last year, Sikaria wrote that adult B-acute lymphoblastic leukemia (B-ALL) doesn’t share the favorable prognosis seen in pediatric patients with the same disease.
“Less than 50 percent of patients experience long-term survival, and for those adults over age 60, long-term survival is only 10 percent. At time of relapse, five-year prognosis is a dismal 7 percent. Novel and less toxic agents are urgently needed,” she continued.
Sikaria called CAR-T cells a highly promising new agent, even in patients who are heavily pretreated.
Dr. Samantha Jaglowski is a hematologist at The Ohio State University Comprehensive Cancer Center. She specializes in stem cell transplants for patients with lymphoma and chronic lymphocytic leukemia.
While she hopes this truly is a breakthrough, she told Healthline she’s hesitant to declare victory too soon.
“It certainly appears promising. I sincerely hope it meets the expectations being put forth,” said Jaglowski.
“It’s an exciting thing to be involved with. There are already many studies in the pipeline for many other kinds of cancers,” she said.
Concerns about CAR-T
There are two main concerns about CAR-T.
The first is the potential for serious side effects.
One of these is a life-threatening reaction called cytokine release syndrome (CRS).
Sikaria said this reaction is common and can occur within hours of the CAR-T cell infusion. But it can be effectively treated.
“The drug also commonly causes reversible neurologic symptoms and a drop in blood counts, which can lead to infection. We have to remember that patients receiving CAR-T cells are battling a disease almost certain to be fatal otherwise, so I do think the risks are outweighed by benefits,” she explained.
Jaglowski agreed that CRS is usually manageable. She noted that there haven’t been enough patients yet to evaluate long-term effects.
“This will not be a first-line therapy until there’s more data behind it. Patients will have had to have a couple of lines of therapy before becoming eligible for this. I’m a lymphoma physician. In lymphoma trials, they require failure of previous lines of therapy. It’s for people who are further on in the disease course and who have fewer options,” said Jaglowski.
The second major concern is the potential cost. Novartis hasn’t put a price tag on it, but industry analysts project that it could hit $500,000 per infusion.
“Hopefully, we’ll see competition in the market from other companies’ CAR-T cells, as a number are in development. Some help from Washington is also needed to bring the cost down,” said Sikaria.
Kesari compared the therapy with other treatments.
“Some drugs we [already] use, especially biologics, cost anywhere from $5,000 to $20,000 a month and involve repeated treatments in a year. Some cost several hundred thousand dollars a year. This is a one-time or few-time treatment. It’s not like you’re getting treatment for years. It puts all the costs upfront. If you get cured, who’s to argue that it’s not worth it?” he said.
Waiting on approval
Sikaria said that unless there’s any new information concerning treatment-related deaths between now and October, the FDA should approve it.
“CAR-T cells are exciting and have high response rates, but we need to see how long-lasting these results are as we continue to shoot for a cure. For now, bone marrow transplant is still an important part of the management of a patient with ALL,” said Sikaria.
Kesari believes the FDA will approve CAR-T due to an unmet need and lack of options for a disease where patients uniformly end up dying.
“This technology of how to modify genes started in the 80s and 90s. Building on that, we learned about the immune system and how to modify it to kill cancers. It’s taken so long to prove value out to the point where we’re getting a drug approval. But it’s been going on for decades,” he continued.
“I commend the people that did this — and to make it work in humans — that’s amazing,” said Kesari.