Session: 653. Myeloma and Plasma Cell Dyscrasias: Clinical-Prospective Therapeutic Trials: Poster II
Hematology Disease Topics & Pathways:
Clinical Trials, Clinical Research, Plasma Cell Disorders, Diseases, Lymphoid Malignancies
Methods: EMN22 is a phase 2, open-label, multicenter study planning to enroll 40 newly diagnosed patients with stage 3B AL amyloidosis from 5 sites in Greece, the Netherlands, Italy and France. Eligible patients should have high-sensitivity troponin T (hsTnT) >54 pg/mL and NT-proBNP ≥8500 pg/mL. Primary treatment consists of daratumumab monotherapy, initially administered intravenously at 16 mg/mL, and since February 2020 administered subcutaneously at a fixed dose of 1800 mg; weekly during Cycles 1-2, every 2 weeks for Cycles 3-6 and every 4 weeks thereafter. Patients who do not achieve a hematologic VGPR or better by Cycle 4 may also receive at investigator’s discretion weekly bortezomib and low dose dexamethasone. Treatment continues until disease progression according to major organ deterioration progression-free survival criteria, start of new therapy, or for a maximum of 2 years. The current analysis includes patients who started treatment at least 3 months prior to the cut-off date (16 June 2021).
Results: Among 17 patients included in this analysis, 9 (53%) are still on treatment and 8 (47%) have discontinued, either due to an adverse event (n=5, 29%), or due to disease progression (n=3, 18%). Most patients were males (n=12, 71%) and median age was 65 years (range 45-84). Eastern Cooperative Oncology Group performance status was 1 for 5 (29%), 2 for 11 patients (65%), and 3 for one patient (6%). Eight (47%) patients had New York Heart Association (NYHA) class II symptoms, and 9 (53%) NYHA class IIIA. At screening, median NT-proBNP was 13,994 pg/mL (range 8,816-40,428), median hsTnT 119.1 pg/mL (range 59.8-692) and median difference of involved to uninvolved free light chains (dFLC) was 553 mg/L (range 49-2823). Apart from the heart, the median number of other organs involved was 1 (range 0-5), with nervous system (n=8, 47%) and kidneys (n=7, 41%) most commonly affected.
The median number of daratumumab infusions was 13 and the median duration of therapy with daratumumab therapy was 3.7 months. Overall, 5 patients (29%) started additional treatment with bortezomib after completion of 3 cycles of daratumumab monotherapy. All 17 patients had at least one treatment-emergent adverse event. Eleven patients (65%) had a serious adverse event (SAE); 9 (53%) had at least one cardiac-related serious adverse event, and one SAE (fatigue) was related to bortezomib. Six patients (35%) suffered a fatal SAE: sepsis (n=1), sudden death (n=3), and cardiac failure (n=2). Most common grade 3 or 4 non-serious AEs were peripheral edema (n=4, 24%), dyspnea (n=3, 18%), and atrial fibrillation (n=2, 12%), and only one non-serious neutropenia grade 3 was related to daratumumab.
The overall response rate was 71%, with 3 patients (18%) achieving CR, 6 (35%) VGPR, and 3 (18%) a PR, with a combined CR+VGPR rate of 53% (9/17). One-, two-, and three-month overall response rates were 65% (n=11), 71% (n=12), and 71% (n=12), and the median time to first response was 7 days while the median time to at least VGPR was 14 days. The 6-month and 12-month OS rate were 70% and 53% respectively (median OS has not been reached).
Conclusions: In this prospective phase 2 study, in patients with high-risk AL amyloidosis (stage 3B), daratumumab monotherapy shows a favorable safety profile and induced very rapid and deep hematologic responses with a median time to first response of 7 days, with 53% of the patients achieving VGPR or better and a 6-month OS of 70%.
Disclosures: Kastritis: Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria. Minnema: Alnylam: Consultancy; BMS: Consultancy; Janssen: Consultancy, Honoraria; Celgene: Other: Travel expenses; Kite/Gilead: Consultancy. Dimopoulos: Amgen: Honoraria; Beigene: Honoraria; BMS: Honoraria; Takeda: Honoraria; Janssen: Honoraria. Huart: Janssen: Honoraria. Leonidakis: Health Data Specialists: Current Employment. Manousou: Health Data Specialists: Current Employment. Sonneveld: Amgen: Consultancy, Honoraria, Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; SkylineDx: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Palladini: Pfizer: Honoraria; Siemens: Honoraria; Janssen Global Services: Honoraria, Other: advisory board fees.
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