ABSENCE OF GPI-NEGATIVE CELLS AT DIAGNOSIS AND LOW NEUTROPHIL COUNT 2 MONTHS AFTER ATGAM BASED TREATMENT ARE ASSOCIATED WITH LOWER 6-MONTH RESPONSE RATE IN ADULTS WITH (VERY) SEVERE APLASTIC ANEMIA
Author(s): ,
Jennifer Tjon
Affiliations:
Hematology,Leiden University Medical Center,Leiden,Netherlands
,
Lisette Bogers
Affiliations:
Hematology,Leiden University Medical Center,Leiden,Netherlands
,
Liesbeth de Wreede
Affiliations:
Medical Statistics,Leiden University Medical Center,Leiden,Netherlands
,
Marco de Groot
Affiliations:
Hematology,University Medical Center Groningen,Groningen,Netherlands
,
Saskia Langemeijer
Affiliations:
Hematology,Radboud University Medical Center,Nijmegen,Netherlands
,
Harry Koene
Affiliations:
Hematology,Antonius Ziekenhuis,Nieuwegein,Netherlands
,
Ellen Meijer
Affiliations:
Hematology,Amsterdam University Medical Center,Amsterdam,Netherlands
,
Erfan Nur
Affiliations:
Hematology,Amsterdam University Medical Center,Amsterdam,Netherlands
,
Marc Raaijmakers
Affiliations:
Hematology,Erasmus Medical Center,Rotterdam,Netherlands
,
Reinier Raymakers
Affiliations:
Hematology,University Medical Center Utrecht,Utrecht,Netherlands
,
Tjeerd Snijders
Affiliations:
Hematology,Medisch Spectrum Twente,Enschede,Netherlands
Stijn Halkes
Affiliations:
Hematology,Leiden University Medical Center,Leiden,Netherlands
EHA Library. Tjon J. Jun 15, 2019; 266738; PS1121
Prof. Jennifer Tjon
Prof. Jennifer Tjon
Contributions
Abstract

Abstract: PS1121

Type: Poster Presentation

Presentation during EHA24: On Saturday, June 15, 2019 from 17:30 - 19:00

Location: Poster area

Background
In aplastic anemia (AA),  allogeneic stem cell transplantation (AlloSCT) is proposed as first line treatment for young patients with a sibling donor.  For all other patients, ATGAM-based immunosuppressive therapy (IST) is the treatment of choice.  After IST, recovery of blood counts can take up to 6 months. Patients with (very) severe AA ((V)SAA), with a neutrophil count  < 0.2 or < 0.5 x 109/L respectively,  remain at risk for infectious complications until blood count recovery. Timely identification of  patients less likely to respond to IST could lead to earlier selection for second line treatment (either alloSCT or second line IST)  in order to prevent prolonged neutropenia. In AA, the presence of glycophosphatidylinositol (GPI) negative cell clones at diagnosis is associated with a better response to IST in some studies. We hypothesized that the absence of GPI negative cells (< 0.1%) before IST and low neutrophil count 2 months after start of treatment are associated with a lower response rate 6 months after IST in (V)SAA patients.

Aims
To Determine whether the presence of GPI negative cell clones before IST and a neutrophil count < 0.2 x 109/L  2 months after IST can predict for treatment refractoriness  at 6 months in adult (V)SAA patients.

Methods
The Dutch registry of adults with acquired aplastic anemia receiving ATGAM (40mg/kg for 4 days intravenously) and ciclosporin as first-line treatment contains data on all consecutive patients treated in 8 major hospitals (LUMC, A-UMC, UMCG, R-UMC, UMCN, EMC, MST and AZN) including baseline and monthly follow-up data. Response at 6 months was defined as transfusion independency and neutrophil count >0.5 x 109/L. Overall survival (OS) was evaluated with the Kaplan-Meier method.

Results
Between 2012 and February 2019, 73 patients, 47 with SAA and 26 with VSAA were registered. Median age at start of IST was 58 years (18-79) and the median follow up time was 21 months. The 6-month OS probability was 96% for SAA and VSAA combined (88% for VSAA and 100% for SAA). 62 patients were evaluable for response 6 months after start of IST. Response was seen in 35 patients (56% (CI 44-68%)). At diagnosis, 36 patients had a detectable GPI negative cell clone. In 25 patients, GPI-negative cells were not detected and in 12 patients the presence of GPI-negative cells was not tested. The response rate 6 months after start of IST for patients with a GPI-negative clone at diagnosis was 63% (CI 47-80%) versus 40% (CI 20-60%) for patients without a GPI-negative clone. Median neutrophil count 2 months after start of IST was available for 57 patients. The majority of the patients (53)  had a neutrophil count ≥ 0.2 x 109/L and in this group the response rate at 6 months was 58% (CI 45-71%). In contrast, of the 4 patients with neutrophil counts <0.2 x 109/L at 2 months after IST, 1 died 3 months after IST and the remaining 3 patients were alive but non-responding to IST at 6 months.

Conclusion
Our analysis of a relatively old (V)SAA patient cohort treated with ATGAM based IST suggests that presence of GPI negative cells at diagnosis and the neutrophil count at 2 months could be used to predict response to first line IST. This knowledge could aid in the decision to start second line treatment (alloSCT or second-line IST)  in this vulnerable patient group.

Session topic: 12. Bone marrow failure syndromes incl. PNH - Clinical

Keyword(s): Allogeneic hematopoietic stem cell transplant, Antithymocyte globulin, Aplastic anemia, Immunosuppressive therapy

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