Phase 2 Study of Daratumumab in Relapsed/Refractory Mantle-Cell Lymphoma, Diffuse Large B-Cell Lymphoma, and Follicular Lymphoma.

BACKGROUND: Daratumumab is a CD38 monoclonal antibody approved for treating relapsed/refractory and newly diagnosed multiple myeloma. Preclinical daratumumab studies demonstrated cytotoxic activity and reduced tumor growth in B-cell non-Hodgkin lymphoma (NHL) subtypes, including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle-cell lymphoma (MCL). PATIENTS AND METHODS: This was a phase 2, open-label, multicenter, 2-stage trial. Patients with relapsed/refractory DLBCL, FL, or MCL with ≥ 50% CD38 expression were eligible for stage 1. Daratumumab (16 mg/kg; 28-day cycles) was administered intravenously weekly for 2 cycles, every 2 weeks for 4 cycles, and every 4 weeks thereafter. Overall response rate was the primary end point. Pharmacokinetic and safety were also evaluated. Stage 2 was planned to further assess daratumumab in larger populations of NHL subtypes if futility criteria were not met. The study was registered with ClinicalTrials.gov (NCT02413489). RESULTS: The trial screened 138 patients resulting in accrual of 15 patients with DLBCL, 16 with FL, and 5 with MCL. Median CD38 expression across treated patients was 70%. Overall response rate was 6.7%, 12.5%, and not evaluable in DLBCL, FL, and MCL cohorts, respectively. The most common grade 3/4 treatment-emergent adverse event was thrombocytopenia (11.1%), and 4 (11.1%) patients discontinued treatment because of treatment-emergent adverse events. Infusion-related reactions occurred in 72.2% of patients (3 patients with grade 3; no grade 4). CONCLUSION: In NHL, the safety and pharmacokinetics of daratumumab were consistent with myeloma studies. Screen-fail rates were high, prespecified futility thresholds were met in 2 cohorts, and the study was terminated. Studies in other hematologic malignancies and amyloidosis are ongoing.

Development of standard estrogen and progesterone receptor immunohistochemical assays for selection of patients for antihormonal therapy.

Estrogen receptor (ER) and progesterone receptor (PR) status in breast carcinomas are considered validated predictive factors for selecting patients for antihormonal therapy. Published surveys have shown a significant rate of disagreement and lack of reproducibility of immunohistochemistry (IHC) results from laboratories around the world. To address these limitations IHC assays for ER and PR were developed using characterized reagents, after careful calibration of the sensitivity and specificity to match established assays previously validated in large clinical studies. The ER assay uses a cocktail of 2 mouse monoclonal antibodies (1D5 and ER-2-123) and the PR assay uses 1 mouse monoclonal antibody (PgR 1294); both are followed by a polymer-peroxidase-based detection system. All antibodies were tested for specificity by epitope mapping. The sensitivity of the new assays was calibrated to be equivalent to previously validated IHC assays followed by a comparison with the validated assays in a concordance study involving over 200 specimens. All slides were scored with the "Allred Score," also used for scoring of the original validated assays. The overall concordance between the new and the established IHC assays was nearly perfect (99%). The concordance study demonstrated greater than 98% positive agreement and 100% negative agreement of the new IHC assays with the previously validated IHC assays. This equivalence establishes the clinical validation of the assays and, as they are based on newer generation reagents and are produced and tested under stringent quality control conditions to ensure their consistency, they add additional advantages to the user and patients.