Hematologic Toxicities: Management of irAEs Guideline (Part 10)

An interview with Dr. Loretta Nastoupil from MD Anderson Cancer Center, author on "Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update." She discusses the identification, evaluation, and management of hematologic toxicities in patients receiving ICPis, including hemolytic anemia among others in Part 10 of this 13-part series. For more information visit www.asco.org/supportive-care-guidelines

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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.

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.

I am joined by Dr. Loretta Nastoupil from the University of Texas M.D. Anderson Cancer Center in Houston, Texas, author on Management of Immune-Related Adverse Events in Patients Treated with Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update, and Management of Immune-Related Adverse Events in Patients Treated with Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline. And today, we're focusing on hematologic toxicities in patients treated with immune-checkpoint inhibitor therapy. Thank you for being here, Dr. Nastoupil.

LORETTA NASTOUPIL: Thanks, Brittany. I'm happy to be here.

BRITTANY HARVEY: Great. Then first 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. Nastoupil, do you have any relevant disclosures that are related to these guidelines?

LORETTA NASTOUPIL: Yes, Brittany. So I have received honorarium for participation in advisory boards from the following companies, including BMS/Celgene, Genentech, Janssen, Novartis, Merck, MorphoSys TG Therapeutics, and Takeda. And I've also received research funding support from BMS/Celgene, Gilead Kite, Genentech, Janssen, Novartis and Takeda.

BRITTANY HARVEY: Thank you for those disclosures. Then let's get into what we're here today to talk about. So what are the immune-related hematologic toxicities addressed in this guideline?

LORETTA NASTOUPIL: So it's important to recognize that hematologic toxicities that are immune-related as a result of immune therapy are infrequent occurrences. So it's important to recognize when they do occur and some of the unique workups given that they are so infrequent. So probably one of the most common is hemolytic anemia.

It's important to recognize that these are cancer patients. And they may have multiple reasons for the development of acute or new onset anemia, but recognizing if they're on either checkpoint inhibitors or immune therapies, it's important to recognize that it might be spurred on as a result of immune-mediated anemia. We advise in terms of history and workup to consider whether or not they've been exposed to new drugs, whether or not they've had a recent insect or snakebite exposure.

The recommended workup includes a CBC with also a peripheral blood smear to look for evidence of hemolysis or macrocytosis. In addition, other hemolytic anemia workup includes evaluation for LDH, haptoglobin, reticulocyte count, bilirubin, and free hemoglobin. Other potential diagnoses on the differential include DIC, so a panel, including coags, PT, INR, and PTT, exploring autoimmune serologies, PNH screening, evaluation for infection such as viral or bacterial causes of hemolysis, and also consideration for bone marrow failure syndrome, including evaluation for potentially reversible causes, such as B12, folate, copper, parvovirus, iron, thyroid, infection, et cetera.

G6PD level is helpful in the evaluation, as well as exploration as I mentioned of potentially new drugs that might be linked, including ribavirin, rifampin, dapsone, interferon, some of the antibiotics, such as cephalosporins, penicillins, NSAIDs, ciprofloxacin, for instance, et cetera. So as part of the workup, if we have excluded alternative causes and we think that the immune-checkpoint inhibitor might be the underlying cause of the autoimmune hemolytic anemia, then generally we will continue unless they have grade 2 or higher toxicity, which is generally a hemoglobin less than 10. In which case, we would recommend to hold the immune-checkpoint inhibitor, again, with significant anemia.

So those with grade 2 or higher, you might consider initiating corticosteroids, including 1.5 to 1 milligram per kilogram per day until improvement. For grade 3 or higher-- so this is more severe anemia, so hemoglobin is less than 8. Generally, we're recommending permanent discontinuation of the checkpoint inhibitor and potentially higher doses, including up to 2 milligrams per kilogram per day of prednisone or corticosteroid equivalent to speed up the recovery.

In regards to transfusion requirements or consideration, we are suggesting you evaluate or consider your local or regional guidelines. We generally do not transfuse for a target hemoglobin greater than seven to eight. And we also recommend supplementation with folic acid.

BRITTANY HARVEY: Great. And then beyond those recommendations for hemolytic anemia, what are the key recommendations for identification, evaluation, and management of acquired thrombotic thrombocytopenia purpura?

LORETTA NASTOUPIL: Sure. So fortunately, TTP is quite rare, but, again, something that is worth exploring. Some of the challenges are in the clinical syndrome. And that it can mimic some of the other toxicities that are covered in other sections, particularly the neurotoxicity section.

But essentially, for patients who have pretty dramatic change in platelet count, again, they may have additional clinical sequelae such as neurologic toxicity or adverse events. It's important to recognize that TTP might be an underlying cause, again, for patients who are on immune-checkpoint inhibitors. This is where a hematology consult early in the clinical course would be particularly of importance to recognize it and potentially to minimize offending agents.

Drug exposure is always important, because many of these patients might have other drugs, in addition to their immune-checkpoint inhibitors, such as chemotherapy, sirolimus, tacrolimus, antibiotics et cetera. And so exploring offending agents is important. An ADAMTS13 level, an inhibitor titer, would be important to send if you're considering TTP, in addition to evaluating the peripheral smear, and the hemolytic anemia workup, as I just mentioned, including LDH, haptoglobin and reticulocyte count.

Exploring infectious etiology, including CMV titers or serology, would be particularly helpful, an additional clinical evaluation, such as brain imaging with CT or MRI, echocardiogram, and EKG would be of help. For all grades of TTP, again, even with a clinical suspicion for the diagnosis, in addition to hematology consult, we recommend stabilizing the patient. That might require care in an acute care setting, making sure that they have adequate organ function and that this is stabilized. For grade 1 or higher, we recommend holding the immune-checkpoint inhibitor.

And you might consider, again, initiation of corticosteroids with 0.5 to 1 milligram per kilogram per day of prednisone or an equivalent. For grade 3 or higher, we would, again, in addition to holding the checkpoint inhibitor and in conjunction with your hematology colleagues, you might initiate a therapeutic plasma exchange. Again, in accordance with existing guidelines, you may consider higher doses of steroids, including methylprednisolone 1 gram IV daily for three days. You could consider some additional supportive agents, such as rituximab or pembrolizumab if the ADAMTS13 level is less than 10 or less than 10% of normal and an inhibitor or elevated ADAMTS13 IgG has been detected.

BRITTANY HARVEY: I appreciate you going through the details for TTP. So then, additionally, this guideline addresses aplastic anemia. So what are the key recommendations for identification, evaluation, and management of aplastic anemia?

LORETTA NASTOUPIL: Yeah. So, fortunately, again, these are quite rare situations. So with aplastic anemia, similar to what we've discussed in terms of workup of anemia, globally, it's important to explore potentially causes of, again, bone marrow failure syndrome. And aplastic anemia is one of those such causes. Exploration of a bone marrow biopsy in conjunction, again, with your hematology consult would be critically important, and exploring potentially reversible causes, again, such as deficiencies and important nutrients, viral etiologies, in addition to parvovirus, CMV, HHV-6 is important to consider and rule out.

But I think the end of the day, a bone marrow biopsy and aspirate is going to be the most helpful assessment to ensure that aplastic anemia has been considered and worked up. In regards to management of aplastic anemia, we're going to hold the immune-checkpoint inhibitor. You may need to provide additional support such as growth factors. And close follow-up, I think is the most critical aspect of this. Sometimes we initiate patients on corticosteroids. We hold the checkpoint inhibitor. And then we may monitor them less frequently. Oftentimes, these patients with high malignancies are going to need to be followed very closely, sometimes weekly or multiple times a week. So in regards to management of aplastic anemia that might be immune-mediated as a result of immune-checkpoint inhibitors and in conjunction with your hematology and colleagues, consideration of management might include administration of horse ATG and cyclosporine, but again transfusion support, growth factor support, even consideration for HLA typing and evaluation first. Stem cell transplantation might be appropriate, particularly for a young patient with minimal comorbidities.

For grade 3 or higher, in addition to these considerations, we're going to hold the checkpoint inhibitor and monitor weekly for improvement. If no response, you might consider repeating immune suppression with Rabbit ATG plus cyclosporine or cyclophosphamide. And for refractory patients, consider eltrombopag plus best supportive care.

BRITTANY HARVEY: Great. Thank you. Those are important notes on the management of aplastic anemia. So then, additionally, what are the key recommendations for the identification, evaluation, and management of lymphopenia?

LORETTA NASTOUPIL: Yeah. I think one of the challenges with lymphopenia, it's common for patients who've had cancer-directed therapy, particularly things like chemotherapy. And so understanding whether or not this is a new onset after exposure to checkpoint inhibitors is one of the critical aspects, in addition to considering alternative causes.

But for patients in which we do think the lymphopenia is a result of the immune-checkpoint inhibitor, we're not generally advising discontinuation or holding of the immune-checkpoint inhibitor, but it is important to consider best supportive measures, including whether or not patients might benefit from monitoring for reactivation of certain viral etiologies, including CMV and HHV-6, for instance, in addition to potential consideration for prophylactic strategies, such as PJP prophylaxis. Also, zoster reactivation might be something that these patients might indeed be at risk for. So as opposed to holding your checkpoint inhibitor and initiating things like corticosteroids, if we have excluded alternative causes and think lymphopenia is a result of the immune-checkpoint inhibitor or as immune-mediated, ensuring that they are receiving best supportive care to mitigate some of their toxicity that may result as the result of the lymphopenia.

BRITTANY HARVEY: Understood. And it's important to note for clinicians that management is different from a lot of the management of the other hematologic toxicities. So then the last hematologic toxicity that was addressed in this guideline was acquired hemophilia A. So what are those key recommendations?

LORETTA NASTOUPIL: Acquired hemophilia A, again, fortunately is very rare and uncommon, but this is one situation where engagement of a hematologist, who is an expert in management of hemophilia, will be critical. So that would potentially be step one. In terms of laboratory assessment, that would be helpful, in addition to your CBC, where you're assessing things like platelet count, coagulation workup, including fibrinogen, PT, PTT, INR, that would be informative.

Patients with acquired hemophilia A will likely have a prolonged activated PTT with a normal PT. So that might be one of the clues. Imaging would be helpful to ensure the patients don't have any signs of spontaneous bleeding or hematosis, such as MRI, CT, or ultrasound, if particularly they have any localizing symptoms. Medication review to look for alternative causes would always be helpful. And determination of the Bethesda unit level of inhibitor would be critical.

In regards to management, we would hold the checkpoint inhibitor, initiate corticosteroids, transfusion support as indicated, and you want to treat the underlying acquired hemophilia with conjunction of a hematologist. For grade 2 or higher, this may require factor replacement. And the choice is usually based on the Bethesda unit of the titer.

Administration of prednisone, in addition to rituximab 375 milligrams per meter squared weekly for four weeks or cyclophosphamide dosed at 1 to 2 milligrams per kilogram per day may be patient-specific. And, again, that decision should be made in conjunction with your hematology consult. Prednisone, rituximab, and cyclophosphamide should be given for a minimum of five weeks.

And factors should be prescribed to increase the level, particularly during bleeding episodes. And, again, the choice of the factor is based on the presence or absence of an inhibitor. For grade 3 or higher, we advise to permanently discontinue the immune-checkpoint inhibitor.

These patients generally will be admitted for stabilization. They do require factor replacement. Bypassing agents may also be required, including factor VII. Caution should be taken in elderly patients and those with coronary artery disease. Corticosteroids, rituximab, and cyclophosphamide should also be considered, transfusion support, if they're having active bleeding.

And if worsening or no improvement, you could consider adding cyclosporine or immune suppression to try and stabilize these patients. Again, acquired hemophilia A requires special clinical and laboratory expertise. This would require consult and potentially even transfer to a specialized center, and consultation with a hemophilia center should be initiated as soon as this is considered or confirmed.

BRITTANY HARVEY: That's a great summary of these recommendations. The expert panel and you clearly put in a lot of work into these recommendations. So then in your view, how will these recommendations for the management of hematologic toxicities impact both clinicians and patients?

LORETTA NASTOUPIL: I think the most important thing are disseminating this information. I think ASCO plays a critical role in helping clinicians first recognize some of the toxicities that are different from what we have traditionally seen with chemotherapy and may have different management strategies. So guidelines, such as this, are critically helpful. Podcasts, such as this, are incredibly helpful to get the information out, recognizing that all of us authors are more than willing to provide additional guidance and are willing to be contacted in this situation where someone's facing one of these unique and rare toxicities and would like some additional guidance in terms of further management.

Hematologic toxicities are sometimes hard to distinguish or maybe potentially hard to recognize, given many of these patients may have been on prior chemotherapy agents, and anemia or thrombocytopenia may not be unusual, but recognizing if it's new or more severe than what has been seen previously and that, at least, consideration of an immune-mediated hematologic toxicity, be considered, because the management might be unique. And so I hope that we've outlined today some of the hematologic toxicities that are rare that may be seen with immune therapy and some of the strategies to work up alternative diagnoses and management if it is indeed immune-mediated toxicity.

BRITTANY HARVEY: Definitely. And I really appreciate you going through these rare but very important toxicities. So thank you for your work on these guidelines and for taking the time to speak with me today, Dr. Nastoupil.

LORETTA NASTOUPIL: Thanks, Brittany.

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. To read the full guideline, 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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