Consolidation Therapy in Newly Diagnosed PCNSL Remains Undefined

The following article features coverage from the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting. Click here to read more of MPR‘s conference coverage.

Compared with non-myeloablative consolidation chemotherapy, myeloablative consolidation after induction therapy does not appear to improve progression-free survival (PFS) among patients with newly diagnosed primary central nervous system lymphoma (PCNSL), according to research presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.

Among patients with PCNSL, the best consolidative therapy is not known. The 2 frequently used options are myeloablative chemotherapy with stem cell transplantation and non-myeloablative chemotherapy. For this randomized phase 2 National Clinical Trials Network study (ClinicalTrials.gov Identifier: NCT01511562), researchers evaluated the comparative safety and efficacy of these 2 consolidative regimens among newly diagnosed patients with PCNSL.

The study consisted of 2 arms. All patients received induction methotrexate (8g/m²; days 1 and 15), temozolomide (150-200mg/m²; days 7-11), and rituximab (cycle 1 days 3, 10, 17, and 24 and cycle 2 days 3 and 10) in 4 28-day cycles; this was followed by 1 cytarabine cycle (2g/m² twice daily on days 1 and 2). After induction therapy, patients in arm A (myeloablative) received consolidation with thiotepa (5mg/kg), carmustine (400 mg/m²), and stem cell transplantation. Patients in arm B received 1 cycle of cytarabine (2g/m² twice daily) with etoposide (40mg/kg infusion).

Overall, 108 evaluable patients were randomly assigned 1:1 to arm A (54 patients) and arm B (54 patients); the median age was 61 years (range, 33-75). A total of 70 patients (36 in arm A and 34 in arm B) completed consolidation.

The median follow-up was 3.8 years. The median PFS in arms A vs B was 6 years vs 2.4 years, respectively (P =.02); 2-year PFS was 73% vs 51%. More patients randomly assigned to arm B discontinued treatment prior to consolidation therapy because of disease progression or death (28% vs 11% in arm A; P =.05).

From start of consolidation, arm A did not show a significant PFS improvement over arm B (2-year PFS estimates: 86% vs 70%, respectively; hazard ratio, 0.58; P =.21).

The 3-year overall survival rate estimates in arms A and B were 87% and 78%, respectively (P =.19). Toxicities were similar between the 2 groups, and no treatment-related mortalities were noted during the consolidation phase.

Disclosure: The study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

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Reference

Batchelor T, Giri S, Ruppert AS, et al. Myeloablative versus non-myeloablative consolidative chemotherapy for newly diagnosed primary central nervous system lymphoma: results of CALGB 51101 (Alliance). J Clin Oncol. 2021;39:(suppl 15; abstr 7506). doi:10.1200/JCO.2021.39.15_suppl.7506

This article originally appeared on Hematology Advisor