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Transcript:

Katherine Banwell:

Well, let’s talk about side effects of CAR T-cell therapy. What advances are being made in managing them?  

Dr. Rahul Banerjee:

Excellent question. So, I break the toxicities into short-term and long-term toxicity of CAR T therapy.  

And this is actually fairly similar for both, regardless of the underlying disease, whereas lymphoma, leukemia, or myeloma, very similar. Just so everyone, just to reorient the audience, short-term toxicities, people often talk about the big two. I’m going to say the big three, actually. The first one is cytokine release syndrome, or CRS, which is inflammation, typically causing fever, sometimes low blood pressure. 

The second is neurotoxicity, or ICANS. For reasons that aren’t entirely understood, sometimes all those chemicals from inflammation can cause people to feel a bit off mentally or cognitively. Sometimes people might not be able to talk, or might not talk correctly, or sometimes have issues along those lines. 

And the third, I would say, is low blood counts or infections. Both the lymphoma, leukemia CAR Ts and the myeloma CAR Ts very rapidly deplete the good plasma cells or the good lymphocytes, the good cells in the bone marrow, and so immediately you see patients at risk of infections. 

And for a complicated number of reasons, one of which being cytokine release syndrome, CRS inflammation within the bone marrow, where all these cancer cells are hiding, the stem cells in the bone marrow hide away, right? They kind of go into a bunker to stay away from all of this. And so patients often have low blood counts for significant amounts of time after CAR T therapy, something called hematotoxicity. 

Those are short-term toxicities. Long-term, very briefly, that risk of infection and low blood counts is still there, I would say, for up to a year after CAR T therapy, sometimes longer for some patients. There is a risk, obviously, of the original cancer coming back, in this case the myeloma, particularly myeloma. 

And three, there are rare delayed toxicities to be on the lookout for. So, one of them, for example, with cilta-cel or Carvykti, the numbers are hard to see what the rate is prospectively because it’s been going down with time.  

But rarely, I would truly in my heart say 1 percent of the time, if not less, patients can get Parkinsonism, where they’re not able to move as rapidly, they’re not able to, they’re kind of shuffling gait, having tremors, et cetera. Not the same as normal Parkinson’s disease, because the normal meds don’t work, just time is often the only thing that really makes a big difference. 

Technically, there’s a box warning on all CAR T therapies now about a risk of second cancers. That risk is not new to anyone who’s ever received any treatment for myeloma because from the very beginning, we tell people that these drugs have been linked to a potential risk of second cancers in the future.  

In terms of strides that are being made to improve that, I think we’re making a lot of improvement. So, I think the biggest thing that we’ve learned, and I remember when I was a trainee, for example, when I was in my medical training, the early days of CAR T therapy – actually out in Philadelphia, I trained at Penn – and there, we were scared about trying to tone down the inflammation.  

When these side effects happen in the short term, the goal is if the patient’s obviously having side effects, and the question is, “Can we not kill the T cells? Can we just dial that down?” Say, “Look, I’m happy the T cells are angry. I’m happy they’re killing the cancer, the myeloma in this case. But can you just dial it down a little bit with a medication called tocilizumab (Actemra), or corticosteroids like dex?” 

We used to be very nervous about doing that because we said, look, the patient’s put all this blood, soil, sweat, and tears right into this CAR T therapy, and we don’t want to do anything that can hinder the T cells from working.  

Now we know that that level of inflammation is not doing anyone any favors at all, and so we’re able to really start these medications to just dial down the immune system faster. As soon as someone has a fever, for example, at many centers, we do consider, within an hour or two, giving one of those medications. Don’t wait till they’re in the ICU, give it then.  So, I think just tweaking our algorithms has made probably the biggest difference, in my mind, to make CAR T safer.  

Other things that have helped, I think, are better understanding of why patients have these other toxicities and strategies to prevent it. And so, for example, the neurotoxicity risk, some of it is part of disease burden. We think that patients who have a lot of disease going into CAR T therapy may have more toxicities. So, giving better treatments as, quote-unquote, “bridging treatment” before CAR T therapy that we have better, newer treatments now, have sometimes helped to really debulk the disease before going to CAR T.  

That’s helped a lot with side effect management. In terms of long-term risk, the third thing that I really encourage all my patients and all my oncologist partners in the community to really push for is the infection risk and how do we prevent it? So, I think probably the biggest thing that we’ve recognized is intravenous immunoglobulin, which is IVIg, which is basically an antibody transfusion.  

When people donate blood, they also donate plasma, often, and the plasma contains antibodies against whatever they themselves have fought off circulating in the area – viruses, colds, et cetera. 

You can take all those antibodies, put them all together into a sterile bag, and give it to the patient who’s gotten CAR T therapy. Because the patient’s gotten CAR T therapy, assuming it’s working, which it normally does for several months, right, to knock out all cells, good and bad immune cells, that patient is not making any antibodies at all. They’re a sitting duck for infections. And so I would say IVIg, using that routinely now is not just the exception once they’re having infections, but even in the absence of infections, just giving it.  

Insurance companies are not happy with me when I suggest that because it’s expensive, but that’s the right thing to do for patients, and I think that has helped a lot, in my experience, for all of these immunotherapies, both CAR T and bispecific antibodies, to lower the risk of infections.