Cerebral sinovenous thrombosis and asparaginase re‐exposure in patients aged 1–45 years with acute lymphoblastic leukaemia: A NOPHO ALL2008 study

Cerebral sinovenous thrombosis (CSVT) is a serious complication during asparaginase therapy in patients with acute lymphoblastic leukaemia (ALL). We identified 46 patients with CSVT among 2651 patients (1‒45 years) treated according to the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol between 2008 and 2018. CSVT cases were prospectively registered in the NOPHO database with retrospective updates. We examined the frequency of asparaginase re‐exposure after CSVT, potential factors associated with asparaginase truncation, and sequelae after CSVT. This work was supported by the Danish Cancer Society and the Danish Childhood Cancer Foundation. The 2.5‐year cumulative incidence of CSVT was 1.9% (95% confidence interval 1.4%–2.5%). The majority of patients (74%, n = 31) were re‐exposed to asparaginase (with low‐molecular‐weight heparin coverage), one of whom had a second CSVT, without neurological sequelae. Patients re‐exposed to asparaginase were earlier in ALL treatment and lacked more asparaginase doses than non‐re‐exposed patients at CSVT diagnosis (median 50 vs. 81 days, p = 0.03; mean 11.2 vs. 8.4 asparaginase doses, p = 0.04). No other examined factors had an impact on asparaginase re‐exposure. At the last follow‐up (median 4.5 years after CSVT), 61% of patients had normal neurological status, and 57% had complete recanalisation of CSVT, with no significant difference between patients re‐exposed and non‐re‐exposed to asparaginase. Our results indicate that re‐exposure to asparaginase is safe after CSVT during anticoagulation.

Low incidence of ABL-class and JAK-STAT signaling pathway alterations in uniformly treated pediatric and adult B-cell acute lymphoblastic leukemia patients using MRD risk-directed approach - a population-based study

Background

ABL-class and JAK-STAT signaling pathway activating alterations have been associated with both a poor post-induction minimal residual disease (MRD) response and an inferior outcome in B-cell acute lymphoblastic leukemia (B-ALL). However, in most of the studies patients received non-uniform treatment.

Methods

We performed a population-based analysis of 160 (122 pediatric and 38 adult) Lithuanian BCR-ABL1-negative B-ALL patients who had been uniformly treated according to MRD-directed NOPHO ALL-2008 protocol. Targeted RNA sequencing and FISH analysis were performed in cases without canonical B-ALL genomic alterations (high hyperdiploids and low hypodiploids included).

Results

We identified ABL-class fusions in 3/160 (1.9%) B-ALL patients, and exclusively in adults (p = 0.003). JAK-STAT pathway fusions were present in 4/160 (2.5%) cases. Of note, P2RY8-CRLF2 fusion was absent in both pediatric and adult B-ALL cases. Patients with ABL-class or JAK-STAT pathway fusions had a poor MRD response and were assigned to the higher risk groups, and had an inferior event-free survival (EFS) / overall survival (OS) compared to patients without these fusions. In a multivariate analysis, positivity for ABL-class and JAK-STAT fusions was a risk factor for worse EFS (p = 0.046) but not for OS (p = 0.278) in adults.

Conclusions

We report a low overall frequency of ABL-class and JAK-STAT fusions and the absence of P2RY8-CRLF2 gene fusion in the Lithuanian BCR-ABL1 negative B-ALL cohort. Future (larger) studies are warranted to confirm an inferior event-free survival of ABL-class/JAK-STAT fusion-positive adult patients in MRD-directed protocols.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07781-6.