Interpreting Safety and Efficacy Data for Tagraxofusp in BPDCN

Uma Borate, MBBS

Associate Professor – Clinical

The James – The Ohio State University Comprehensive Cancer Center

Columbus, OH

DISCUSSION QUESTIONS:

• What are your impressions of the data from the phase 1/2 study (NCT02113982) of tagraxofusp-erzs (Elzonris) for blastic plasmacytoid dendritic cell neoplasm (BPDCN)?​

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• How likely are you to consider this drug if you had a patient with a BPDCN diagnosis?​

UMA BORATE, MD: I wanted to get your thoughts on the data from this phase 1/2 study, the adverse event profile of the drug, and how comfortable you feel considering this as a therapy option if you diagnose your patient with BPDCN.

BOB BLOOM, MD: If we had a patient who had this diagnosis, I think this is the appropriate therapy. It’s a bit cumbersome, but it's no more or less than a lot of the other [therapies] we use.

BORATE: Would you admit your patient [to a hospital] for the first cycle?

BLOOM: There would be a problem not admitting your patient because it says on the package insert that it needs to be given as an inpatient [with observation for at least 24 hours after the last infusion].¹ God forbid you have a fluke situation, you [would be in trouble].

BORATE: Absolutely, I agree with that.

MALEK SAFA, MD: Have you tried albumin infusion during the treatment if the [serum] albumin level goes down and you want to continue, or does that not help?

BORATE: I have not had to do that. Luckily, all of my patients have been very well nourished, and so I haven't. I know of several [physicians] who have had to do that, especially after that first cycle; by the time the second cycle came around, the albumin was still between 3.0 g/dL and 3.5 g/dL, where they have given the patient albumin prior to dosing to avoid significant CLS [capillary leak syndrome]. That's not uncommon.

PALLAVI JASTI, MD: This is my first time hearing about the drug. There are not a lot of other treatments for this disease. It's a targeted therapy and some of the AEs we are familiar with treating other cancers. If I had a potential patient, I think I would be comfortable recommending this treatment.

BORATE: I will say…sometimes when you start your first insurance pre-approval process, it can take a few more days than you would normally expect with other diseases because it's rare. But I have not had a problem once the insurance company has reviewed the records, and they've confirmed that this is the diagnosis, because [tagraxofusp has] such a straight frontline indication.

SHEELA TEJWANI, MD: Do you do the CNS [central nervous system] imaging only if they have symptoms? A second [question] is, are the hematopathologists comfortable making this diagnosis in big institutions or even smaller institutions?

BORATE: We do CNS diagnostics and LP [lumbar puncture] for everybody because there's a high rate of CNS involvement, just like with AML [acute myeloid leukemia] that presents with sinus involvement or testicular involvement. You always do an LP with intrathecal [chemotherapy] to make sure there's no CNS involvement. We always do that before starting tagraxofusp.

I think the hematopathology question is a mixed bag. If you have a senior hematopathologist who has seen this several times, has diagnosed this, keeps it on their radar, and has that culture in your institution, there's more comfort [about diagnosing BPDCN]. But I don't think it's that well known that everybody is comfortable with it or thinks about it. They might need more clinical context or prompting, depending on who you have in your practice.

BAIDEHI MAITI, MD: Other than the low albumin, are there any other predictors of CLS in these patients?

BORATE: I think the other [predictor—although] I don't know if it's necessarily a predictor vs patients who don't do well if they even have mild CLS—is patients with compromised heart function. If they have coronary artery disease, or they have history of CHF [congestive heart failure], it doesn't take a lot of CLS for them to tip over into CHF. Those are the patients [whom] you want to watch for. It is not uncommon in older patients.

SAFA: If the patient responds well, [but] they don't go to allogeneic stem cell transplant, do they continue forever? If they go into complete remission, how many cycles [should they receive]?

BORATE: Technically you can continue [indefinitely], until you see intolerable AEs or progression.¹ Most patients end up dose reducing [or] extending the time between cycles, all the usual modifications we end up doing for our patients who are on treatment for a long time. A lot of patients will unfortunately progress.

SAFA: Do you use any prophylactic antibiotics, antivirals, [and] antifungals, or do you not need to?

BORATE: Not routinely. If my patients are neutropenic I do what I do for my patients with AML, but if they're not, then I don't do it proactively.

_Reference:

_{1. Elzonris. Prescribing information. Stemline Therapeutics, Inc; 2023. Accessed November 13, 2023. https://tinyurl.com/mr3pwzu2}