Real world outcomes with the use of Inotuzumab Ozogamicin in relapsed/refractory B-cell acute lymphoblastic leukemia

Sep 28, 2026

Uploaded by Damian

Relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL) carries poor long-term outcomes, and Inotuzumab Ozogamicin (InO) has shown meaningful activity in trials. A retrospective single-center study (Jan 2020–Dec 2024) analyzed 49 treated patients receiving InO using either fixed or body-surface-area–based dosing. Overall response was 57.14%, with many responders achieving MRD negativity. Febrile neutropenia and post-treatment hepatic sinusoidal obstruction syndrome (SOS) were key toxicities, including cases after transplant. One-year survival and event-free survival were reported, with additional comparisons and literature context on SOS risk and dosing strategies.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

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Background and study rationale

Patient cohort and InO dosing approaches

Treatment responses and MRD outcomes

Toxicities: febrile neutropenia and SOS

Survival outcomes and follow-up

Context from CIBMTR and prior studies

Blood Cancer [Journal](Journal www.nature.com/bcj)[ www.nature.com/bcj](Journal www.nature.com/bcj) CORRESPONDENCE OPEN Real world outcomes with the use of Inotuzumab Ozogamicinin relapsed/refractory B cell acute lymphoblastic leukemia © The Author(s) 2025 Blood Cancer Journal (2025)15:216; [https://doi.org/](https://doi.org/)[ ](https://doi.org/)[10.1038/s41408-025-01448-w](10.1038/s41408-025-01448-w) Relapsed/refractory B-cell acute lymphoblastic leukemia (R/R BALL) is associated with dismal clinical outcomes, with long-term cure rates of 10% with conventional therapies [1] . Inotuzumab Ozogamicin (InO) is a humanized anti-CD22 monoclonal antibodydrug conjugate that has shown signiﬁcant activity in adult patients with R/R B-ALL as demonstrated in the phase III INOVATE trial [2] . There is limited real-world data on the use of InO for R/R B-ALL with reports mainly from the global north [3–5] . There is reasonable consensus even in a low-middle income country setting for the use of InO [6] but limited data on clinical outcomes [7], especially in the setting of dose modiﬁcations due to ﬁnancial constraints. Following Institutional Review Board Approval, a retrospective study was conducted to analyze the data of patients with R/RB-ALL at our center from January 2020 to December 2024 . During the study period, 127 patients had R/R B-ALL at our center. Amongst these, 83 patients were treated at our center. Of these, 49 (median age 24 years, range 6–68) received InO for refractory (n = 9) or relapsed (n = 40) B-ALL. The details of these patients are shown in Table 1. Cytogenetics was available for 46 patients and of these, 6 patients had Philadelphia chromosome positive (Ph + ) B-ALL. Due to cost considerations, some patients received ﬁxed doses of 1 mg vial of InO on either days 1, 8, and 15 (n = 25) or days 1 and 15 (n = 2) . The remainder of the patients received the dose as per body surface area (n = 22) . The median dose of InO was 1 . 72 (range 1 .23–2. 1) mg/m2/cycle amongst the responders versus 1 . 54 (range 0 .61–1. 82) mg/m2/ cycle amongst the non-responders (p value 0.42) . Among the 44 patients for whom the CD22 data was available, the median CD22 expression was 98.3 (16.9–99.9)% among the respondersand 94.92 (1.13–99.8)% among the non-responders (p value 0 .46) . Twenty-eight (57.14%) patients had a response (deﬁned as CR/ CRi as per ELN 2024 guidelines [8]), amongst whom 20 (71.4%) were MRD negative. Among the responders, 19 (67.8%) underwent a subsequent transplant or cellular therapy (18 patients underwent an allogeneic stem cell transplant (conditioning details are mentioned in Supplementary Table 1) and 1 patient underwent CAR-T cell therapy) . In our cohort, 15 (30.6%) patients developed febrile neutropenia, 10 of the 49 patients who received InO (20.4%) experienced hepatic sinusoidal obstruction syndrome (SOS) (see Supplementary Table 2), of which 9 (i.e., 50% of the transplant cohort) occurred post-transplant despite the use of prophylactic ursodiol in all patients in the peri-transplant period. The median time from last InO to transplant was 45 (30–120) days. The median dose of InO amongst those who had severe SOS (n = 8) was 1.79 (range 1.51–2) mg/m2/cycle when compared to 1 .61 (range = 0.75–2. 1) mg/m2/cycle amongst patients who did not. There was no statistically signiﬁcant correlation between the occurrence of SOS and the number of doses of InO (p value 0.42), cumulative dose of InO (p value 0.42) or time interval between last dose of InO and transplant (p value 0.47) . Of the 10 who developed SOS (see Supplementary Table 2), 8 had severe/very severe SOS (as deﬁned by the EBMT criteria [9]) . Five had resolution of SOS, and the median OS after recovery from SOS was 14 months (range, 2–27 months) . The 1-year overall survival for the entire cohort was 51.7% ± 8.1%, with the 1-year event-free survival (event deﬁned as death or relapse) being 32.4% ± 8% . The 1-year overall survival for

FAQs

What was the study design and patient timeframe?

A retrospective study was conducted after Institutional Review Board approval, analyzing patients with R/R B-ALL treated at a single center from January 2020 to December 2024.

How were Inotuzumab Ozogamicin doses administered, and what responses were observed?

Patients received either fixed 1 mg vial dosing on specified days or dosing by body surface area. The response rate was 57.14%, and most responders were MRD negative.

What hepatic toxicity was reported, and how frequently did it occur?

Hepatic sinusoidal obstruction syndrome (SOS) occurred in 20.4% of patients who received InO, with some cases developing after transplant despite prophylactic ursodiol.

What were the key survival outcomes for the cohort?

For the entire cohort, the 1-year overall survival was 51.7% and 1-year event-free survival was 32.4%. Patients undergoing transplant/CAR T had higher 1-year overall survival than those not undergoing transplant/CAR T.

Sep 28, 2026

Uploaded by Damian