Glucocorticoids are universally used in the treatment of acute lymphoblastic leukemia (ALL), and leukemia cell resistant to glucocorticoids confers a poor prognosis. To elucidate mechanisms of glucocorticoid resistance, we determined the sensitivity to prednisolone of primary leukemia cells from 444 newly diagnosed ALL patients, revealing significantly higher expression of caspase 1 (CASP1) and its activator NLRP3 in glucocorticoid resistant leukemia cells, due to significantly lower somatic methylation of CASP1 and NLRP3 promoters. Over-expression of CASP1 resulted in cleavage of the glucocorticoid receptor, diminished glucocorticoid-induced transcriptional response and increased glucocorticoid resistance. Knockdown or inhibition of CASP1 significantly increased glucocorticoid receptor levels and mitigated glucocorticoid resistance in CASP1 overexpressing ALL. Our findings establish a new mechanism by which the NLRP3/CASP1 inflammasome modulates cellular levels of the glucocorticoid receptor and diminishes cell sensitivity to glucocorticoids. The broad impact on glucocorticoid transcriptional response suggests this mechanism could also modify glucocorticoid effects in other diseases.

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Key Points Comprehensive study of glucocorticoid-induced osteonecrosis identifies glutamate receptor gene variants as risk factors.

PURPOSE Pegaspargase (PEG-ASP) has largely replaced native Escherichia coli asparaginase (L-ASP) in the treatment of acute lymphoblastic leukemia because of its longer half-life and lower immunogenicity. Risk factors for allergic reactions to PEG-ASP remain unclear. Here, we identify risk factors for reactions in a front-line acute lymphoblastic leukemia trial and assess the usefulness of serum antibodies for diagnosing allergy and predicting rechallenge outcome. PATIENTS AND METHODS PEG-ASP was administered to 598 patients in St Jude’s Total XVI study. Results were compared with Total XV study ( ClinicalTrials.gov identifiers: NCT00549848 and NCT00137111 ), which used native L-ASP. Serum samples (n = 5,369) were analyzed for anti–PEG-ASP immunoglobulin G by enzyme-linked immunosorbent assay. Positive samples were tested for anti–polyethylene glycol (PEG) and anti–L-ASP. We analyzed potential risk factors for reactions and associations between antibodies and reactions, rechallenge outcomes, and PEG-ASP pharmacokinetics. RESULTS Grade 2 to 4 reactions were less common in the Total XVI study with PEG-ASP (81 [13.5%] of 598) than in the Total XV study with L-ASP (169 [41.2%] of 410; P = 1.4 × 10−23). For Total XVI, anti-PEG, not anti–L-ASP, was the predominant component of anti–PEG-ASP antibodies (96%). In a multivariable analysis, more intrathecal therapy (IT) predicted fewer reactions ( P = 2.4 × 10−5), which is consistent with an immunosuppressant contribution of IT. Anti–PEG-ASP was associated with accelerated drug clearance ( P = 5.0 × 10−6). Failure of rechallenge after initial reactions was associated with anti–PEG-ASP ( P = .0078) and was predicted by the occurrence of angioedema with first reaction ( P = .01). CONCLUSION Less IT therapy was the only independent clinical risk factor for reactions to PEG-ASP. PEG, and not L-ASP, is the major antigen that causes allergic reactions. Anti–PEG-ASP has utility in predicting and confirming clinical reactions to PEG-ASP as well as in identifying patients who are most likely to experience failure with rechallenge.

Background Glucocorticoids and asparaginase, used to treat acute lymphoblastic leukemia (ALL), can cause hypertriglyceridemia. We compared triglyceride levels, risk factors, and associated toxicities in two ALL trials at St. Jude Children's Research Hospital with identical glucocorticoid regimens, but different asparaginase formulations. In Total XV (TXV), native Escherichia coli l‐asparaginase was front‐line therapy versus the pegylated formulation (PEG‐asparaginase) in Total XVI (TXVI). Procedure Patients enrolled on TXV (n = 498) and TXVI (n = 598) were assigned to low‐risk (LR) or standard/high‐risk (SHR) treatment arms (ClinicalTrials.gov identifiers: NCT00137111 and NCT00549848). Triglycerides were measured four times and were evaluable in 925 patients (TXV: n = 362; TXVI: n = 563). The genetic contribution was assessed using a triglyceride polygenic risk score (triglyceride‐PRS). Osteonecrosis, thrombosis, and pancreatitis were prospectively graded. Results The largest increase in triglycerides occurred in TXVI SHR patients treated with dexamethasone and PEG‐asparaginase (4.5‐fold increase; P <1 × 10−15). SHR patients treated with PEG‐asparaginase (TXVI) had more severe hypertriglyceridemia (>1000 mg/dL) compared to native l‐asparaginase (TXV): 10.5% versus 5.5%, respectively (P = .007). At week 7, triglycerides did not increase with dexamethasone treatment alone (LR patients) but did increase with dexamethasone plus asparaginase (SHR patients). The variability in triglycerides explained by the triglyceride‐PRS was highest at baseline and declined with therapy. Hypertriglyceridemia was associated with osteonecrosis (P = .0006) and thrombosis (P = .005), but not pancreatitis (P = .4). Conclusion Triglycerides were affected more by PEG‐asparaginase than native l‐asparaginase, by asparaginase more than dexamethasone, and by drug effects more than genetics. It is not clear whether triglycerides contribute to thrombosis and osteonecrosis or are biomarkers of the toxicities.

Key Points The rs6021191 variant in NFATC2 is associated with an increased risk of asparaginase hypersensitivity and is an expression quantitative trait locus associated with expression of NFATC2. Exome interrogation confirms the importance of the HLA-DRB1*07:01 allele in asparaginase hypersensitivity.

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Remission induction therapy for acute lymphoblastic leukemia (ALL) includes medications that may cause hepatotoxicity, including asparaginase. We used a genome-wide association study (GWAS) to identify loci associated with elevated alanine transaminase (ALT) levels after induction therapy in children with ALL enrolled on St. Jude Children’s Research Hospital (SJCRH) protocols. Germline DNA was genotyped using arrays and exome sequencing. Adjusting for age, body mass index, ancestry, asparaginase preparation and dosage, the PNPLA3 rs738409 (C>G) I148M variant, previously associated with fatty liver disease risk, had the strongest genetic association with ALT (P = 2.5×10−8). The PNPLA3 rs738409 variant explained 3.8% of the variability in ALT, and partly explained race-related differences in ALT. The PNPLA3 rs738409 association was replicated in an independent cohort of 2,285 patients treated on Children’s Oncology Group protocol AALL0232 (P = 0.024). This is an example of a pharmacogenetic variant overlapping with a disease risk variant.