A phase 2 study of ibrutinib maintenance following first-line high-dose methotrexate-based chemotherapy for elderly patients with primary central nervous system lymphoma

BACKGROUND

Elderly patients account for nearly 70% of all primary central nervous system lymphoma (PCNSL) cases. They cannot tolerate aggressive treatment and have poor prognosis with a median overall survival (OS) of less than 2 years and progression-free survival (PFS) of 6-16 months. Ibrutinib penetrates the blood-brain barrier and has shown activity in PCNSL.

METHODS

This prospective study investigated whether ibrutinib maintenance is feasible, and whether it can benefit elderly PCNSL patients in terms of expected 2-year PFS. It is an open label, phase 2 study in newly diagnosed PCNSL patients 60-85 years old who responded to first-line high-dose methotrexate (HDMTX)-based treatment with partial or complete response. Ibrutinib maintenance (560 mg/d) was continued until disease progression or intolerable toxicity.

RESULTS

Twenty patients were enrolled, with a median age of 72 years (range, 61-80). Median time on ibrutinib maintenance was 12.5 (range, 2-46) months. Twelve patients stopped treatment: five due to central nervous system relapse and seven due to adverse events that were mainly grade 2. Five patients died (25%) all due to relapse. The 1- and 2-year PFS are 90% and 72.6%, respectively, and the 2-year OS is 89%.

CONCLUSIONS

The study reached its primary end points and also showed that ibrutinib maintenance is tolerated reasonably well by the elderly. Therefore, this study supports the concept that ibrutinib maintenance should be further evaluated as an optional consolidation measure in the elderly.

Infectious complications and long-term outcomes in patients with diffuse large B-Cell lymphoma and diabetes mellitus

Febrile neutropenia (FN) is a major complication in patients with diffuse large B-Cell lymphoma (DLBCL). Diabetes mellitus (DM) has deleterious effects on the immune system resulting in an increased risk of infections. We evaluated patients with DLBCL who started frontline treatment with R-CHOP, and compared outcomes according to presence of DM comorbidity. Between 2013 and 2018, 218 patients with DLBCL were included. 46 patients (21%) had DM. Rate of admissions for FN was higher for patients with DM (0.7 vs. 0.46 admissions/patient, p = .016), also after age and gender-matched subgroup analysis (p = .004). Improved glycemic control during FN hospitalizations was associated with shorter hospitalizations. Metformin was associated with improved median overall survival in diabetic patients (89 vs. 64 months, p = .018). In conclusion, Patients with DLBCL and DM had higher rates of FN hospitalizations. Improved glycemic control during FN hospitalization was associated with shorter length of stay.

Effect of steroid treatment on the diagnostic yield of baseline 18f-fluorodeoxyglucose positron emission tomography in aggressive B cell lymphoma

Aggressive B cell lymphoma often requires prompt steroid treatment, even before baseline ¹⁸f-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and definitive treatment, to alleviate symptoms or prevent organ damage. Since lymphoma is a steroid-sensitive malignancy, there are concerns that steroids might affect the results of FDG PET/CT and decrease its diagnostic yield. The aim of the current study was to evaluate the effect of steroids administered before baseline PET/CT on the maximum standardized uptake value (SUVmax) and additional PET/CT parameters. Retrospective review of the database in a tertiary medical center yielded 178 patients newly diagnosed with aggressive B cell lymphoma between January 2017 and May 2020 who had an available baseline FDG PET/CT scan. The cohort was divided into patients who received steroids before PET/CT (n = 47) and those who did not (n = 131), and the groups were compared for SUVmax and additional PET/CT parameters. The steroid-treated group had a higher disease stage and lactate dehydrogenase level compared to the steroid-naïve group, with a trend toward a higher international prognostic index. There was no significant between-group difference in SUVmax (P = 0.61). This finding remained consistent across steroid treatment durations and dosage regimens. Further evaluation revealed a significantly larger mean tumor volume and a trend toward a higher tumor metabolic burden in the steroid-treated group, yet no between-group difference in SUV mean or other PET/CT parameters. In this retrospective analysis of patients with aggressive B cell lymphoma, steroid prophase prior to baseline PET/CT did not decrease the diagnostic yield of the scan. However, further studies are required to fully appreciate the impact of steroids on PET CT parameters.

Abstract 3849: Exosomes in polycythemia vera: "mini platelets" with oncogenic and thrombogenic potential

Polycythemia vera (PV) is a classical "myeloproliferative neoplasm" characterized by clonal proliferation of myeloid progenitor cells caused by their acquisition of a mutation in the JAK2 gene. Its common complications are thrombosis and second primary malignancies. Secreted from virtually all cell types, exosomes are extracellular vesicles that carry bioactive cargo derived from their cells of origin. When engulfed, their cargo may alter the phenotype of the recipient cells. For example, neoplastic exosomes modulate the cellular makeup of bystander cells. Therefore, since mutated JAK2 is present in virtually all PV-patients, we hypothesize that PV-derived exosomes (hereafter PV-exo) carry the mutated JAK2 oncogene and are taken up by non-clonal cells, thus contributing to the thrombotic manifestations and oncogenic potential of patients with PV. We isolated and characterized exosomes from PV-patients and from the Human erythroleukemia (HEL) cell line (hereafter HEL-exo). We exposed normal cells implicated in thrombosis and skin cells to these exosomes and examined the cells' phenotypic changes and activation after exposure. Using Sanger sequencing we discovered that both PV-exo and HEL-exo, like their parental cells, carry the mutated JAK2 transcripts, allowing clonal cells to export oncogenes to distant, non-clonal sites. Our preliminary findings suggest that these exosomes promote pro-coagulant and malignant phenotypes in multiple ways. Thrombin generation assay pointed to a significantly higher generation of thrombin in the presence of PV-exo than those derived from healthy donors. Similarly, flow cytometry analysis revealed that PV-exo increased the expression of platelet activation markers. Moreover, Trans Endothelial Electrical Resistance (TEER) assay results suggest that HEL-exo induces endothelial dysfunction. Furthermore, using the Sulforhodamine B assay, we found that exposure to HEL-exo increased the proliferation of normal keratinocytes. In summary, we developed the concept of exosomes as “mini metastasis” that might promote disease manifestations either directly or indirectly. Since unlike solid tumors, hematological malignancies do not metastasize, exosomes derived from neoplastic hematological cells may fulfill this function. Such exosomes may spread oncogenes (e.g., mutated JAK2), damage non-clonal tissues (e.g., endothelial dysfunction) or act as a miniature reflection of their cells of origin (e.g., exosomes as mini platelets) in a parallel way to "real" metastasis; this concept may affect treatment related decisions. For example, by reducing clonal burden, early treatment even in “low risk” patients may prevent exosomal spread and exosomal-dependent damage to distant tissues. The results of our study highlight PV-exo as promoters of PV-complications, thrombosis and malignant transformation.

Citation Format: Orit Uziel, Adi Shacham-Abulafia, Galia Spectre, Ester Ziv, Karyn Revital Geiger, Zinab Sarsor, Neria Ron, Einat Beery, Pia Raanani, Shoshana Revel-Vilk, Mira Naamad, Uri Rozovski. Exosomes in polycythemia vera: "mini platelets" with oncogenic and thrombogenic potential [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3849.

Hemophagocytic lymphohistiocytosis as a harbinger of aggressive lymphoma: a case series

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory syndrome, which can manifest either secondary to a variety of underlying causes, or due to a primary genetic defect. Malignancy is the most common underlying disease in adults with HLH, with lymphomas being the most common malignancy. Lymphoma-associated hemophagocytic syndrome (LAHS) typically follows a rapidly progressive clinical course and is associated with poor prognosis. We herein present four patients with HLH associated with aggressive lymphoma. At initial presentation, the underlying etiology of the HLH was unclear. Two patients were eventually diagnosed with anaplastic large cell lymphoma, while the other two had diffuse large B cell lymphoma. Two of the patients experienced rapid clinical deterioration, one at diagnosis and the other at relapse, and both died prior to diagnosis of lymphoma despite HLH-directed therapy. These cases highlight the need for intensive management in adults with HLH without a clear etiology, especially in cases when lymphoma-associated HLH is suspected. We describe the current pitfalls in diagnosis and treatment of LAHS and discuss possible ways to improve patient management.

Necrosis of the skin over the metacarpal as a result of functional fracture-bracing. A report of three cases

Use of a functional brace for the treatment of a fracture of a metacarpal caused necrosis of the skin under the dorsal pad in three patients. In order to evaluate the mechanism of the necrosis, we made in vivo and in vitro measurements of pressures that are typically found under the pad. We found that the pressures easily exceeded 260 millimeters of mercury. Pressures of this magnitude have been shown to cause necrosis of the skin. Orthopaedic surgeons should be aware of this problem when using the brace, and perhaps a wider pad should be used to distribute the force.

Nitrogen-13-labeled nitrite and nitrate: distribution and metabolism after intratracheal administration

Radioactive nitrogen-13 from nitrite (NO2-) or nitrate (NO3-) administered intratracheally or intravenously without added carrier to mice or rabbits was distributed evenly throughout most organs and tissues regardless of the entry route or the anion administered. Nitrogen-13 from both anions was distributed uniformly between plasma and blood cells. We found rapid in vivo oxidation of NO2- to NO3- at concentrations of 2 to 3 nanomoles per liter in blood. Over 50 percent oxidation within 10 minutes accounted for the similar nitrogen-13 distributions from both parent ions. The oxidation rates were animal species-dependent. No reduction of 13NO3- to 13NO2- was observed. A mechanistic hypothesis invoking oxidation of 13NO2- by a catalase-hydrogen peroxide complex accounts for the results. These results imply a concentration dependence for the in vivo fate of NO2- or nitrogen dioxide.