CAR-T Cell Therapy: Management of irAEs Guideline (Part 2)

An interview with Dr. Bianca Santomasso from Memorial Sloan Kettering Cancer Center and Dr. Monalisa Ghosh from the University of Michigan Health System, authors on "Management of Immune-Related Adverse Events in Patients Treated With Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline." They discuss recommendations for management of irAEs in patients treated with CAR T-Cell Therapy in Part 2 of this 13-part series. For more information visit www.asco.org/supportive-care-guidelines

TRANSCRIPT

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SPEAKER: The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions. Guests on this podcast express their own opinions, experience, and conclusions. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.

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BRITTANY HARVEY: Hello, and welcome to the ASCO Guidelines podcast series brought to you by the ASCO Podcast Network. A collection of nine programs covering a range of educational and scientific content, and offering enriching insight into the world of cancer care. You can find all the shows, including this one, at asco.org/podcasts.

My name is Brittany Harvey, and today we're continuing our series on the management of immune-related adverse events. ASCO has developed two guidelines for the management of immune-related adverse events-- one for patients treated with immune checkpoint inhibitor therapy and a second for patients treated with CAR T-cell therapy.

In our last episode, you heard an overview of the Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update. Today, we'll be focusing on the Management of Immune-Related Adverse Events in Patients Treated with Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline, and we'll have authors join us for future episodes to discuss the key recommendations for organ-specific management for patients treated with immune checkpoint inhibitor therapy.

Today, I am joined by Dr. Monalisa Ghosh, from the University of Michigan Health System in Ann Arbor, Michigan and Dr. Bianca Santomasso from Memorial Sloan Kettering Cancer Center in New York, New York, authors on both Management of Immune-Related Adverse Events in Patients Treated with Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline and Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update.

Thank you both for being here, Dr. Ghosh and Dr. Santomasso. In addition, I'd like to note that ASCO takes great care in the development of its guidelines and ensuring that the ASCO Conflict of Interest policy is followed for each guideline.

The full Conflict of Interest information for this guideline panel is available online with the publication of the guidelines in the Journal of Clinical Oncology. Dr. Ghosh, do you have any relevant disclosures that are directly related to this guideline?

MONALISA GHOSH: No. I do not have any relevant disclosures.

BRITTANY HARVEY: Thank you. And, Dr. Santomasso, do you have any relevant disclosures that are directly related to this guideline?

BIANCA SANTOMASSO: Yes. I'd like to disclose that I've served as a paid consultant for Celgene, Janssen Pharmaceutical, and Legend Biotech for advising them on the topics of CAR T-cell therapy side effects.

BRITTANY HARVEY: Thank you. Then, getting into these immune-related adverse events-- first, Dr. Ghosh, can you give us an overview of the scope and purpose of this guideline?

MONALISA GHOSH: Sure. The purpose of this guideline is to offer expert guidance and recommendations on the management of immune-related adverse events in patients treated with chimeric antigen receptor or CAR T-cell therapy.

This guideline offers guidance on the diagnosis, evaluation, and management of the most common toxicities of CAR T-cell therapy, which includes Cytokine Release Syndrome-- or CRS-- and immune effector associated neurologic syndrome-- or ICANS.

As well as other potential, but less common toxicities, such as Hemophagocytic Lymphohistiocytosis-- or HLH-- B-cell aplasia, prolonged and recurrent cytopenias, Disseminated Intravascular Coagulation-- or DIC-- and infections.

BRITTANY HARVEY: Great. Thank you. Then, Dr. Santomasso-- looking at this guideline, there's a few overarching recommendations. So, what are those general recommendations for the management of immune-related adverse events in patients receiving CAR T-cell therapy?

BIANCA SANTOMASSO: Yes. The overarching recommendations are, really, first to recognize that these side effects exist. And that, as such, it's important to recognize that patients who develop these toxicities or side effects after CAR T-cell therapy need to be evaluated, or managed in, or transferred to a specialty center that has experience with the management of these toxicities.

They're new toxicities. This is a new therapy. And patients are increasingly going to be managed in, or treated in, the outpatient setting, and, as such, they need to remain within a short distance of the treating center for about four to eight weeks post-therapy, and they should then return to their treating center upon experiencing any toxicities.

Finally, as its flu season and infection season, it is recommended that inactivated influenza and COVID-19 vaccination be performed on patients and also family members as well. And any patient who does have an active infection, the CAR T-cell infusion should be delayed until that infection has been successfully treated or controlled.

I often make a final point, which is that the immunogenicity of and efficacy of COVID-19 vaccines is uncertain in these patients with these agents, but the potential benefits outweigh the risks and uncertainties for most patients.

BRITTANY HARVEY: Thank you. Those are important points for patients and treating clinicians. So then, Dr. Ghosh-- as you mentioned, this guideline addresses the seven most common CAR-T-related toxicities, and I'd like to review the key recommendations for each of those.

So let's start with, what are the key recommendations for identification, evaluation, and management of cytokine-release syndrome?

MONALISA GHOSH: Well, Cytokine Release Syndrome is one of the two major toxicities that occur immediately or within a short time period after infusion of CAR T-cells. We have defined Cytokine Release Syndrome, or CRS, as an immune-mediated phenomenon that's characterized by various symptoms that are indicative of immune activation and inflammation.

And patients may experience signs and symptoms that could include fever, hypotension, hypoxia, tachycardia, shortness of breath, rash, nausea, headache, and various other symptoms that are a little less common. These symptoms are caused primarily by the release of cytokines.

Cytokines are the messengers of the immune system, and most of them are released by bystander immune and non-immune cells. We know that the onset of Cytokine Release Syndrome is variable depending on the CAR T-cell product that's used, as well as the patient population that's treated.

But it generally occurs anywhere from two to seven days after infusion of CAR T-cells, and in some rare cases can occur even a little bit later. A standard grading system has been developed and grade CRS, or Cytokine Release Syndrome, based on three parameters-- fever, hypotension, or low blood pressure; and hypoxia or low oxygen levels.

CRS is primarily managed with IL-6 antagonists because IL-6 is an inflammatory cytokine that has been shown to mediate a lot of the systemic effects that we see from Cytokine Release Syndrome. And one of the treatments is the monoclonal antibody tocilizumab, which acts against-- or blocks-- the IL-6 receptor.

CRS that is refractory to tocilizumab is generally treated with steroids. Then there's limited experience with additional therapies, especially in the setting of CRS, that does not respond to tocilizumab or steroids. There are other anti IL-6 therapies available. For example, siltuximab, which binds to IL-6 itself rather than the IL-6 receptor. However, there have been no direct comparative studies of these agents. Anakinra, which is also an IL-1 receptor antagonist has also been shown to mitigate CRS in some CAR T-cell recipients that have high grade CRS.

BRITTANY HARVEY: OK. Thank you for reviewing those management strategies. So, following that-- Dr. Santomasso, what are key recommendations for identification, evaluation, and management of immune effector cell-associated neurotoxicity syndrome?

BIANCA SANTOMASSO: Sure. Immune Effector Cell-associated Neurotoxicity Syndrome-- also known as ICANS-- is the second most frequent severe toxicity that can be seen after CAR T-cell therapy. So, what is ICANS? These are transient neurological symptoms that occur in the days after infusion, most commonly with CD19 CAR T-cell therapy.

And the clinical manifestations of ICANS include encephalopathy, which is confusion, behavioral changes, expressive aphasia, or other language disturbance, change in handwriting or other fine motor impairment or weakness, and tremor and headache can also be seen.

In more severe cases, patients can become obtunded with a depressed level of consciousness or even develop seizures, and they may require a higher level of ICU care, such as intubation for airway protection. And in very rare cases, malignant cerebral edema may develop, which may be fatal.

ICANS can occur at the same time as Cytokine Release Syndrome, or can also occur several days after or shortly after CRS resolves, so it's important to have a high index of suspicion even after Cytokine Release Syndrome has resolved, but typically the side effects are self-limited and occur within the one month after infusion.

Most symptoms lasts between 5 and 17 days, and the time of onset duration and severity of ICANS may really vary depending on the CAR T-cell product used or the disease state of the patient. So, what do I mean by that? Patients with high disease burden seem to be at increased risk for severe ICANS, so kind of knowing the disease that the patient has and the burden of disease is important.

And then also there may be product-specific differences as well, so reviewing the product label is important as well because each may have its own risk evaluation and mitigation strategies that inform both the duration and the frequency of monitoring for ICANS after infusion.

For evaluation of ICANS, we recommend, again, the ASTCT ICANS grading system. These allow for monitoring of several different aspects of neurologic function in these patients. Mental status changes are really what define the onset of ICANS.

So for CRS, it's fever; for ICANS, it's mental status changes. And the severity of the mental status change can be determined by a standardized score known as the ICE score, which stands for Immune Effector Cell-associated Encephalopathy score.

This is a simple 10-point scoring metric where points are assigned for orientation to year, month, city, hospital, ability to name three objects, ability to follow simple commands, write a standard sentence, and count backwards from 100 by tens.

And for children younger than age 12 or those with developmental delay, The Cornell Assessment of Pediatric Delirium, also known as the CAPD, can be used in placement of the ICE assessment. Prior to CAR infusion, patients should be evaluated, including with an ICE score, for their baseline neurologic status.

And what's nice is that this ICE assessment can be used as a daily screen after CAR infusion for the onset of ICANS during at-risk period. Then, other than the ICE score, there are four other neurologic domains that contribute to ICANS grading, and that's level of consciousness, seizures, severe motor weakness, and signs and symptoms of elevated intracranial pressure or cerebral edema, and patients are graded according to the most severe symptom in any of the five domains.

So for patients who develop ICANS, it's recommended that they have workup, including blood work, CRP, CBC, comprehensive metabolic panel, fibrinogen, and coagulation tests. Neuroimaging with a non-contrast CT of the brain should be done and considering MRI of the brain in patients who are stable enough.

In addition, electroencephalogram and lumbar puncture should be considered. And the electroencephalogram is really to rule out subclinical seizures, and the lumbar puncture is to assess the opening pressure-- or the pressure within the central nervous system-- and also to send studies to rule out infection. And again, these all have to be considered on an individual case by case basis, but are things to keep in mind.

So for treatment of ICANS, the mainstay of treatment is, really, supportive care and corticosteroids. Tocilizumab, while it seems to rapidly resolve Cytokine Release Syndrome and most symptoms, actually does not resolve ICANS and may worsen it, so steroids are really typically used.

The typical steroid is dexamethasone at a dose of 10 milligrams, and the interval really depends on the grade of the ICANS. Because of the possibility that tocilizumab may worsen neurotoxicity, ICANS really takes precedence over low grade CRS when the two occur simultaneously.

And patients who don't show improvement within 24 hours after starting steroids or other supportive measures should have CSF evaluation and neuroimaging. Often treatment of seizures-- many patients are put on Keppra and levetiracetam or other anti-seizure medicine if they develop ICANS, and patients with grade 3 or greater ICANS may need an ICU level of care and escalation of steroid doses.

The steroids are continued until ICANS improves to grade 1 and then tapered as clinically appropriate. And the most important thing to remember is that ICANS just needs to be monitored very closely as patients may worsen as some steroids are tapered. They also may improve rapidly after steroids are started, so steroids should be tapered quickly as patients improve.

And, again, as with CRS, there's limited experience with other agents, such as Anakinra and siltuximab, but those could be considered in severe or refractory cases.

BRITTANY HARVEY: Understood. I appreciate you going through when and how clinicians should screen for ICANS and those key management points. So, in addition to that-- Dr. Ghosh, what are the key recommendations regarding cytopenias?

MONALISA GHOSH: So cytopenias can occur post-CAR T-cell infusion, and they can occur either in the early phase or in the later phase after CAR T-cell infusion. Meaning that they can occur early within the first few days to weeks post-CAR T-cell therapy or could even occur months to years later.

These cytopenias include anemia, thrombocytopenia, leukopenia, neutropenia. Many patients may present with fatigue, weakness, shortness of breath, lightheadedness, frequent infections, fevers, bruising, and bleeding, and the symptoms usually are consistent with how they would present otherwise with anemia, thrombocytopenia, or neutropenia.

Acute cytopenias within three months of CAR T-cell therapy are more common. This is due to usually the lymphodepleting chemotherapy that is administered prior to CAR T-cell therapy. Most patients receive a combination of fludarabine and cyclophosphamide prior to CAR T-cell infusion, or they may receive another agent, such as bendamustine. Most patients also come into CAR T-cell therapy with low lymphocyte counts from previous therapies.

Early cytopenias, as I mentioned, are generally due to lymphodepleting chemotherapy or other recent therapies. There also could be an immune-mediated process due to the CAR T-cells. Usually prolonged cytopenias which occur beyond three months post-CAR T-cell infusion can be seen in a small number of patients.

And the mechanism of prolonged cytopenias is really unclear at this time, but likely multifactorial. Most recipients of CAR T-cells who have prolonged cytopenias beyond three months post-CAR T-cell infusion should have a standard workup to rule out other common causes, such as vitamin or nutritional deficiencies.

They should also have testing such as bone marrow biopsy and scans to rule out relapse disease-- relapse lymphoma or leukemia, for instance, that could be causing these cytopenias. Other examples would be myelodysplastic syndrome or other bone marrow failure syndromes. So cytopenias are generally managed with supportive care including growth factor and transfusion support. This applies to both cytopenias in the early period post-CAR T-cell therapy or more delayed prolonged cytopenias.

In patients who have prolonged cytopenias of unclear cause that could be immune-mediated, other interventions such as high dose IVIG or even steroids could be considered depending on the situation. For those that have cytopenias in the first few months post-CAR T-cell therapy, generally they are monitored and treated with supportive care, and these cytopenias eventually resolve in the majority of patients.

BRITTANY HARVEY: Great. Those are important considerations. Then, Dr. Santomasso, what are the key recommendations regarding Hemophagocytic Lymphohistiocytosis?

BIANCA SANTOMASSO: The major recommendations for the identification, evaluation, and management of Hemophagocytic Lymphohistiocytosis, or HLH-- this is also known as macrophage activation syndrome. First, let's just start by saying that this is a dysfunctional immune response, and it's basically characterized by macrophages which are revved up and hyperactive and also possibly lymphocytes as well.

There are high levels of pro-inflammatory cytokines during this state and tissue infiltration, and hemophagocytosis, and organ damage. This can occur outside of the context of CAR T-cell therapy, either as a primary HLH or secondary HLH that can be either triggered by infections, or autoimmune disease, or cancer-- especially hematological malignancies, but HLH has also been observed as a rare complication of CAR T-cell therapy. And outside of the setting of CAR T-cell therapy, HLH is defined by fever, cytopenias, hyperferritinemia-- or high ferritin level-- as well as bone marrow hemophagocytosis.

And what's interesting is that this is very similar to what's seen during Cytokine Release Syndrome, and that can make it difficult for patients who have moderate to severe CRS to distinguish that from HLH. The laboratory results may be very similar. So the key to recognizing HLH is really to have it on your differential even though it occurs rarely after CAR T-cell therapy. It may occur with slightly different timing and may require more aggressive treatment.

The lab alterations can include, again, as I mentioned, these elevated levels of several cytokines, such as interferon gamma. We can't normally send those in the hospital or the clinic, but sometimes soluble IL-2 receptor alpha can be sent and serum ferritin can be sent, and that's an especially useful marker.

There have been diagnostic criteria for CAR T-cell-induced HLH that have been proposed, and these conclude very high ferritin levels-- over 10,000-- and at least two organ toxicities that are at least grade 3, such as transaminitis, increased bilirubin, renal insufficiency or oliguria, or a pulmonary edema, or evidence of hemophagocytosis in bone marrow or organs.

Unlike other forms of HLH that occur outside of the context of CAR T-cell therapy, the patients may not have hepatosplenomegaly, lymphadenopathy, or overt evidence of hemophagocytosis. So just because a patient may not show those yet doesn't mean that HLH shouldn't be considered.

If we see patients that have a persistent fever without an identified infection source or worsening fever, we basically should be considering HLH and doing the appropriate workup and treatment. Patients with HLH often have low fibrinogen, high triglycerides, and also cytopenias as well.

The treatment-- just as there's an overlap kind of in the signs and symptoms, the treatment and the clinical management overlaps as well with CRS, so tocilizumab is typically administered. But corticosteroids should really be added for these patients, especially if there's clinical worsening or grade 3 or greater organ toxicity.

And if there's insufficient response after 48 hours of corticosteroid therapy plus tocilizumab, many centers consider adding another medication such as Anakinra. I'll finally make a comment that, outside of the context of CAR T-cell therapy, HLH is sometimes treated with cytotoxic chemotherapy, such as etoposide.

This approach generally is not used as a first line for patients undergoing CAR T-cell therapy due to etopiside's documented toxicity to T lymphocytes. And generally, the corticosteroids, plus the anti IL-6 agent, plus Anakinra is considered the first line of management.

BRITTANY HARVEY: Got it. That's an important note on the management of HLH, and a great note on distinguishing CRS and HLH. So in addition, Dr. Ghosh-- what are the recommendations for management of B-cell aplasia?

MONALISA GHOSH: B-cell aplasia, it's a disorder that's caused by low numbers or absent B-cells. And this is particularly relevant to CD19 directed CAR T-cell therapy, which is what most of the CAR T-cell therapies that are available right now target. They target CD19, and CD19 is present on normal as well as malignant B-cells.

So most patients who receive anti-CD19 CAR T-cell therapy will develop B-cell aplasia at some point, and B-cell aplasia may be temporary or prolonged. It usually does, on one hand, indicate ongoing activity of the CD19 CAR T-cells and can be used as a surrogate marker.

And increase in CD19 CAR T-cells could, in some patients, signal impending relapse, or dysfunction, or absence of activity of CD19 CAR T-cells. B-cell aplasia in CAR T-cell recipients is really due to, as I mentioned, an on-target, off-tumor effect. It can be prolonged and there is variability in rates of prolonged B-cell aplasia.

The most significant consequence of B-cell aplasia is that it can lead to low immunoglobulin production. And immunoglobulin production is a very important part of the immune response by providing antibody-mediated immunity, so patients may present with frequent infections and low immunoglobulin levels.

For most CAR T-cell recipients, this can be managed with infusions of Intravenous Immunoglobulins-- IVIG. However, the presence of B-cell aplasia can also present other challenges-- especially during this current pandemic, as Dr. Santomasso alluded to earlier, that it is unclear if patients will be able to mount a sufficient enough antibody response to the COVID-19 vaccines available since they cannot produce significant amounts of antibodies. This is an active area of research. However, we do advise that all CAR T-cell recipients do get the COVID vaccine and also other seasonal vaccines, such as the influenza vaccine.

So it remains to be seen. We need some more long-term follow-up studies on how many people who receive CD19-directed CAR T-cell therapy will have prolonged B-cell aplasia and what the consequences will be. At this time, it is suggested that patients have their IgG levels monitored and-- if possible-- their actual B-cell numbers monitored.

And if their IgG levels drop below a certain number, then they may receive IVIG infusions intermittently. We recommend in this guideline using 400 as a possible cutoff for IgG levels prior to administering IVIG. However, if patients have higher IgG levels and they have recurrent or life threatening infections, infusion of IVIG is recommended as a consideration to help boost the antibody response.

BRITTANY HARVEY: OK. As you mentioned, those challenges are particularly relevant now. So then, Dr. Santomasso, what are the key recommendations regarding Disseminated Intravascular Coagulation?

BIANCA SANTOMASSO: Disseminated Intravascular Coagulation is a disorder that's characterized by systemic pathological activation of blood clotting mechanisms, which results in both clot formation throughout the body and also bleeding. There's an increased risk of hemorrhage as the body is depleted of platelets and other coagulation factors.

So it's basically important for clinicians to be aware that DIC-- or Disseminated Intravascular Coagulation-- can occur after CAR T-cell therapy, and it can occur either with or without concurrent Cytokine Release Syndrome. The treatment is primarily supportive care and replacing the factors, such as fibrinogen-- based on the levels-- and also replacing factors based on partial thromboplastin time and bleeding occurrences.

But corticosteroids and IL-6 antagonist therapy can be used if there is concurrent CRS or in the setting of severe bleeding complications. There is limited evidence for other interventions.

BRITTANY HARVEY: Great. Appreciate you reviewing those. So then, the last category of toxicity addressed in this guideline-- Dr. Ghosh, what are the key recommendations for identification, evaluation, and management of infections?

MONALISA GHOSH: So a variety of infections can be seen after CAR T-cell therapy. And there are many factors that can lead to infection after CAR T-cell therapy including the presence of cytokines, such as neutropenia or leukopenia and B-cell aplasia that we earlier discussed-- leading to low immunoglobulin production and protection.

As well as the increased risk of infection due to use of high-dose steroids to treat CAR T-cell-related toxicities, such as ICANS or CRS. Early after the infusion of CAR T-cell therapy-- that is, within three months-- patients often develop neutropenia due to lymphodepleting chemotherapy and/or the CAR T-cells themselves.

And these patients are particularly susceptible to infection, so most of the infections that occur early on tend to be bacterial infections, and a few fungal infections have been observed as well. Patients who receive high-dose steroids for high grade CRS or ICANS have been shown to have increased serious infectious complications including bacterial infections, fungal infections, as well as viral reactivations.

Infectious complications that occur later are often due to hypogammaglobulinemia due to B-cell aplasia and reduced production of immunoglobulins. And treatment is typically directed at the infectious source, as it would be even if these patients did not have CAR T-cell therapy.

There are some prophylactic antimicrobials that are recommended for CAR T-cell recipients who have prolonged cytopenias. Especially those with prolonged neutropenia should be on some sort of bacterial and/or fungal prophylactic antimicrobials.

Patients should also be monitored for hypogammaglobulinemia long term and should receive intravenous immunoglobulins as needed. As we have mentioned a couple of times already, being very aware that these patients are also more susceptible to seasonal infection, such as influenza, is important, and so vaccinations are very important for this patient population. Vaccinating against influenza and vaccinating against COVID-19.

BRITTANY HARVEY: Thank you both for reviewing those key points for the most common CAR T-related toxicities. So, just to wrap us up-- Dr. Santomasso-- in your view, how will this guideline impact both clinicians and patients?

BIANCA SANTOMASSO: Well, I think we've seen now that cell therapy is really one of the major advances in cancer treatment in the past decade. And I think it's reasonable to expect more of these cell therapies to be developed, and we'll hopefully see their use extend beyond very specialized centers.

But CAR T-cell therapy side effects are manageable if they're recognized, so I think this guideline helps that, and they're reversible with proper supportive care. They can be serious and they require close vigilance and prompt treatment. But, again, we believe this guideline and recommendations will help members of clinical teams with both the recognition and management of all of these toxicities, and that will help patients by increasing their safety.

BRITTANY HARVEY: Great. That's important to note that these toxicities can be severe, but are also manageable. So I want to thank you both for your work on these guidelines and for taking the time to speak with me today, Dr. Santomasso and Dr. Ghosh.

BIANCA SANTOMASSO: Our pleasure.

MONALISA GHOSH: Absolutely. It was my pleasure.

BRITTANY HARVEY: And thank you to all of our listeners for tuning in to the ASCO Guidelines podcast series. Stay tuned for additional episodes on the management of immune-related adverse events in patients treated with immune checkpoint inhibitors. To read the full guidelines, go to www.asco.org/supportive care guidelines.

You can also find many of our guidelines and interactive resources in the free ASCO Guidelines app available in iTunes or the Google Play store. If you have enjoyed what you've heard today, please rate and review the podcast, and be sure to subscribe so you never miss an episode.

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