Childhood B-Cell Acute Lymphoblastic Leukemia Following SARS CoV-2 Infection: A Potential Second "Hit" in Leukemogenesis.

The Coronavirus Disease 2019 (COVID-19) pandemic has become the worst pandemic in modern history. The lack of prior immunity to the virus has resulted in a high mortality rate, though children have fared better than adults, overall. We present a case of a child who developed B-cell acute lymphoblastic leukemia 1 week following a symptomatic COVID-19 infection. It is possible that this viral infection provided the "second hit" posited to occur in pediatric leukemogenesis as proposed by Dr Greaves, with his initial viral exposure occurring several weeks earlier.

CD14/16 monocyte profiling in juvenile myelomonocytic leukemia.

Monocyte subset analysis by flow cytometry has been shown to be a useful diagnostic tool in chronic myelomonocytic leukemia in adults. An increase in the classical monocyte fraction (CD14++/CD16-) greater than 94.0% of total monocytes is considered highly sensitive and specific in distinguishing chronic myelomonocytic leukemia from other myeloproliferative disorders. In a pilot study of juvenile myelomonocytic leukemia cases, we noted that CD14++/CD16- monocyte fraction was >95% in de novo juvenile myelomonocytic leukemia (JMML) with somatic PTPN11 mutations but normal in those with monosomy 7 or Noonan syndrome. Monocyte subgroup profiling by itself is not diagnostic of JMML but may distinguish molecular subgroups within JMML.

Intravenous Ferric Carboxymaltose in Children with Iron Deficiency Anemia Who Respond Poorly to Oral Iron.

OBJECTIVE: To assess the benefits and risks of intravenous (IV) ferric carboxymaltose (FCM) in children with iron deficiency anemia (IDA). STUDY DESIGN: In a retrospective cohort study of patients seen at our center, we identified all FCM infusions in children with IDA over a 12-month period through a query of pharmacy records. Clinical data, including hematologic response and adverse effects, were extracted from the electronic medical record. RESULTS: A total of 116 IV FCM infusions were administered to 72 patients with IDA refractory to oral iron treatment (median age, 13.7 years; range, 9 months to 18 years). Median preinfusion and postinfusion hemoglobin values were 9.1 g/dL and 12.3 g/dL, respectively (at 4-12 weeks after the initial infusion; n = 53). Sixty-five patients (84%) experienced no adverse effects. Minor transient complications were encountered during or immediately after 7 infusions. CONCLUSION: FCM administered as a short IV infusion without a test dose proved to be safe and highly effective in a small yet diverse population of infants, children, and adolescents with IDA refractory to oral iron therapy.

Real-world outcomes on platinum-containing chemotherapy for EGFR-mutated advanced nonsquamous NSCLC with prior exposure to EGFR tyrosine kinase inhibitors.

Background: Front-line therapy with an EGFR tyrosine kinase inhibitor (TKI) is the standard of care for treating patients with advanced nonsquamous NSCLC with the common sensitizing EGFR exon 19 deletion and exon 21 L858R point mutations. However, EGFR TKI resistance inevitably develops. The optimal subsequent therapy remains to be identified, although platinum-containing chemotherapy regimens are often administered. Our objectives were to describe baseline characteristics, survival, and subsequent treatment patterns for patients with advanced nonsquamous NSCLC with EGFR exon 19 deletion or L858R mutation who received a platinum-based combination regimen after front-line EGFR TKI therapy. Methods: This retrospective study used a nationwide electronic health record-derived deidentified database to select adult patients with advanced nonsquamous NSCLC, evidence of EGFR exon 19 deletion or L858R mutation, and ECOG performance status of 0-2 who initiated platinum-containing chemotherapy, with or without concomitant immunotherapy, from 1-January-2011 to 30-June-2020 following receipt of any EGFR TKI as first-line therapy or, alternatively, a first- or second-generation EGFR TKI (erlotinib, afatinib, gefitinib, dacomitinib) as first-line therapy followed by the third-generation EGFR TKI osimertinib as second-line therapy. Data cut-off was 30-June-2022. The Kaplan-Meier method was used to estimate overall survival (OS) after initiation of pemetrexed-platinum (n=119) or any platinum-based combination regimen (platinum cohort; n=311). Results: The two cohorts included two-thirds women (65%-66%) and 57%-58% nonsmokers; median ages were 66 and 65 years in pemetrexed-platinum and platinum cohorts, respectively. Median OS was 10.3 months (95% CI, 8.1-13.9) from pemetrexed-platinum initiation and 12.4 months (95% CI, 10.2-15.2) from platinum initiation; 12-month survival rates were 48% and 51%, respectively; 260 patients (84%) had died by the end of the study. Conclusion: The suboptimal survival outcomes recorded in this study demonstrate the unmet need to identify more effective subsequent treatment regimens for patients with EGFR-mutated advanced nonsquamous NSCLC after EGFR TKI resistance develops.

Pembrolizumab Plus Chemotherapy for Metastatic NSCLC With Programmed Cell Death Ligand 1 Tumor Proportion Score Less Than 1%: Pooled Analysis of Outcomes After Five Years of Follow-Up.

BACKGROUND: We report long-term outcomes from a pooled analysis of patients with previously untreated metastatic NSCLC with programmed cell death ligand 1 (PD-L1) tumor proportion score (TPS) less than 1% enrolled in phase III studies of pembrolizumab plus chemotherapy versus placebo plus chemotherapy. METHODS: This exploratory pooled analysis included individual patient data from the KEYNOTE-189 global (NCT02578680) and Japan extension (NCT03950674) studies of metastatic nonsquamous NSCLC without EGFR or ALK alterations and the KEYNOTE-407 global (NCT02775435) and People's Republic of China extension (NCT03875092) studies of metastatic squamous NSCLC. Patients received pembrolizumab or placebo plus pemetrexed and cisplatin or carboplatin in KEYNOTE-189 and pembrolizumab or placebo plus carboplatin and paclitaxel or nab-paclitaxel in KEYNOTE-407. PD-L1 TPS was centrally assessed using PD-L1 IHC 22C3 pharmDx (Agilent Technologies, Carpinteria, CA). RESULTS: Overall, 442 patients were included in this analysis (pembrolizumab plus chemotherapy, n = 255; chemotherapy, n = 187). The median follow-up was 60.7 (range, 49.9‒72.0) months. Pembrolizumab plus chemotherapy improved overall survival (hazard ratio, 0.64; 95% confidence interval [CI]: 0.51‒0.79) and progression-free survival (hazard ratio, 0.66; 95% CI: 0.54‒0.81) versus chemotherapy. The 5-year overall survival rates (95% CI) were 12.5% (8.6%‒17.3%) versus 9.3% (5.6%‒14.1%). Grades 3 to 5 treatment-related adverse events occurred in 59.1% of patients for pembrolizumab plus chemotherapy and 61.3% for chemotherapy. CONCLUSION: With approximately 5 years of follow-up, pembrolizumab plus chemotherapy provided clinically meaningful and durable improvements in survival outcomes versus chemotherapy alone in patients with previously untreated metastatic NSCLC with PD-L1 TPS less than 1%. These results continue to support pembrolizumab plus chemotherapy as a standard of care in this patient population. CLINICALTRIALS: gov, NCT02578680 (KEYNOTE-189 global), NCT03950674 (KEYNOTE-189 Japan extension), NCT02775435 (KEYNOTE-407 global), NCT03875092 (KEYNOTE-407 People's Republic of China extension).

Characterizing bulk rigidity of rigid red blood cell populations in sickle-cell disease patients.

In this work, we utilized a parameterization model of ektacytometry to quantify the bulk rigidity of the rigid red blood cell (RBC) population in sickle cell disease (SCD) patients. Current ektacytometry techniques implement laser diffraction viscometry to estimate the RBC deformability in a whole blood sample. However, the diffraction measurement is an average of all cells present in the measured sample. By coupling an existing parameterization model of ektacytometry to an artificially rigid RBC model, we formulated an innovative system for estimating the average rigidity of the rigid RBC population in SCD blood. We demonstrated that this method could more accurately determine the bulk stiffness of the rigid RBC populations. This information could potentially help develop the ektacytometry technique as a tool for assessing disease severity in SCD patients, offering novel insights into the disease pathology and treatment.

Oxidation of the natural amino acids by a ferryl complex: kinetic and mechanistic studies with peptide model compounds.

Kinetic and mechanistic studies detailing the oxidation of substrates derived from the 20 natural amino acids by the ferryl complex [Fe(IV)(O)(N4Py)](2+) are described. Substrates of the general formula Ac-AA-NHtBu were treated with the ferryl complex under identical conditions ([Ac-AA-NHtBu] = 10 mM, [Fe] = 1 mM, 1:1 H(2)O/CH(3)CN), and pseudo-first-order rate constants were obtained. Relative rate constants calculated from these data illustrated the five most reactive substrates; in order of decreasing reactivity were those derived from Cys, Tyr, Trp, Met, and Gly. Second-order rate constants were determined for these substrates by varying substrate concentration under pseudo-first-order conditions. Substrates derived from the other natural amino acids did not display significant reactivity, accelerating decomposition of the ferryl complex at a rate less than 10 times that of the control reaction with no substrate added. Ferryl decomposition rates changed in D(2)O/CD(3)CN for the Cys, Tyr, and Trp substrates, giving deuterium kinetic isotope effects of 4.3, 29, and 5.2, respectively, consistent with electron-transfer, proton-transfer (Cys and Trp), or hydrogen atom abstraction (Tyr) mechanisms. Decomposition rates for [Fe(IV)(O)(N4Py)](2+) in the presence of the Met and Gly substrates were identical in H(2)O/CH(3)CN versus D(2)O/CD(3)CN solvents. A deuterium kinetic isotope effect of 4.8 was observed with the labeled substrate 2,2-d(2)-Ac-Gly-NHtBu, consistent with [Fe(IV)(O)(N4Py)](2+) abstracting an alpha-hydrogen atom from Ac-Gly-NHtBu and generating a glycyl radical. Abstraction of alpha-hydrogen atoms from amino acid substrates other than Gly and oxidation of side chains contained in the amino acids other than Cys, Tyr, Trp, and Met were slow by comparison.