Grading toxicity
In contrast, Dr. Nastoupil said that a consensus has been reached for grading acute toxicity. Of note, fever is now considered an essential element of cytokine release syndrome.
“The first thing we see [with cytokine release syndrome] is fever, generally speaking,” Dr. Nastoupil said. “That will prompt a workup for infection because these patients are going to be neutropenic. And we initiate broad spectrum antimicrobials.”
She said that some patients treated with CAR T-cell therapy have had disseminated fungal infections, so clinicians need to be on the lookout for septic shock.
To assess neurotoxicity, the team at MD Anderson uses an objective scoring system, called “CARTOX.” This helps maintain consistency when facing broadly different neurological presentations.
“There’s such a wide ranging spectrum of patients that are undergoing neurotoxicity you can’t expect someone, even myself, to be consistent when you are trying to tease out how serious it is,” Dr. Nastoupil said.
With CARTOX, nurses can easily score patients and call clinicians with results. Still, this doesn’t eliminate difficulties inherent to managing neurotoxicity, particularly when it is severe.
“I’d say one of the areas that is still very challenging is when [patients with neurotoxicity] are no longer responding,” Dr. Nastoupil said. “You have to be very mindful of seizure activity. We’ve had a couple of patients with status [epilepticus]. You don’t see seizure activity physically, but when you do an EEG, you pick it up.”
Dr. Nastoupil added that most centers are now giving patients prophylactic levetiracetam (Keppra) to lower seizure risk.
Choosing therapy
When selecting between the two therapies currently approved by the Food and Drug Administration – tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (Yescarta) – based on safety, Dr. Nastoupil said that rates of cytokine release syndrome appear similar, but neurotoxicity rates may differ.
“Cytokine release syndrome in my opinion is probably more similar than different in terms of grade 3 or higher because tocilizumab and steroids work quite well in aborting those toxicities,” Dr. Nastoupil said. “But neurotoxicity still sticks out in my mind as the most striking difference, where with axicabtagene you see more grade 3 or higher neurotoxicity, though very, very few deaths as a result of this. But it’s very challenging in terms of management.”
According to Dr. Nastoupil, comparisons between CAR T-cell therapies have been complicated by differences in clinical trial methodologies. However, she offered a general conclusion regarding efficacy.
“[W]hat I’ll tell you, at the end of the day, is [that existing CAR T-cell therapies] all seem to sort of settle out around 30%-40% in terms of durable responses,” Dr. Nastoupil said.
Dr. Nastoupil concluded her presentation with an overview and look to the future.
“I do think [CAR T-cell therapy] is transformative, particularly for our chemo refractory patients,” she said. “There is nothing else like it. The problem right now is that it is only durable in 40% of patients. So can we be better at selecting out patients that are more likely to respond? Does introducing this in earlier lines of therapy increase that fraction of patients that are potentially cured?”
Considering these questions, she said: “We need more patients. We need more data. We need longer follow-up to understand the nuances of this therapy.”
Dr. Nastoupil previously reported financial relationships with Celgene, Genentech, Gilead, Merck, Novartis, Spectrum, and TG Therapeutics.