Outcomes of therapeutic plasma exchange for the treatment of patients with multiple myeloma cast nephropathy.

Current treatment guidelines of myeloma cast nephropathy (MCN) recommend the institution of plasma cell-directed therapy and consideration of therapeutic plasma exchange (TPE), with the goal of rapid reduction of the serum free light chain (sFLC). However, the role of TPE continues to remain a subject of debate. The goal of this retrospective bi-institutional study was to evaluate the clinical outcomes of TPE in combination with systemic therapy. Eighty patients were included in this analysis, of whom 72.5% had ≥50% drop in their initial involved sFLC. At 3 months from TPE initiation, the overall hematologic response rate (ORR) was 67.5% with a very good partial response or better (≥VGPR) rate of 40%. At 6 months, ORR was 57.5%, with ≥VGPR rate of 49%. The renal response rate at 3 and 6 months was 47.5% and 43.75%, respectively; the overall renal response rate was 48.75%. On multivariable analysis, every one unit increase in baseline creatinine (odds ratio [OR] 0.76, p = 0.006), and achievement of ≥VGPR (OR 21.7 p < 0.0001) were significantly associated with renal response. Also, a ≥50% drop in sFLC was favorably associated with renal response (OR 3.39, p = 0.09). With a median follow-up of 36.4 months, the median overall survival (OS) was 11 months. On multivariable analysis, achievement of renal response (hazard ratio [HR] 0.3, p < 0.0001) and newly diagnosed disease (NDMM; HR 0.43, p = 0.0055) were associated with improved OS. Among NDMM patients, those treated with daratumumab-based regimens had a trend for better OS (p = 0.15), compared to other regimens, but the difference was not significant. At the end of follow-up, an estimated 40.4% of patients who were on dialysis were able to become dialysis independent. In conclusion, our study highlights the poor survival of patients with MCN. Achievement of early renal response is crucial for prolonged OS, with daratumumab-based therapies showing promise.

Apheresis practice variation during the COVID-19 pandemic: Results of a survey.

BACKGROUND: The COVID-19 pandemic affected healthcare delivery across all specialties including apheresis. To describe the changes in apheresis service practices that occurred during the pandemic, the American Society for Apheresis (ASFA) Apheresis Medicine Attending Physician Subcommittee conducted a survey study. STUDY DESIGN AND METHODS: A 32-question survey was designed and distributed to 400 ASFA physician members on September 7, 2022. Attending physicians responded to questions about whether and how apheresis service practices changed during the COVID-19 pandemic compared with the time period prior to the pandemic in terms of: (1) procedure types and volumes, (2) patient consultation workflow, and (3) the use of telemedicine. Descriptive analyses were reported as number and frequency of responses. RESULTS: The survey response rate was 13.8% (55/400). Of these respondents, 96.4% (53/55) were attending physicians. The majority of respondents (42/53, 79.2%) indicated that the types of procedures performed during COVID-19 compared to pre-pandemic did not change. Most frequently for apheresis procedure volume, respondents reported: no change in their monthly inpatient volume (21/47, 44.7%) and a decrease in their monthly outpatient volume (28/46, 60.9%). Prior to COVID-19, 75.0% (30/40) of respondents performed consultations at bedside for inpatients and 67.4% (29/43) performed consultations at bedside for outpatients. Bedside consultations decreased in both settings during the pandemic but were still most frequently performed by attending physicians. At the same time, the use of telemedicine increased for 15.4% of survey respondents during COVID-19. CONCLUSION: Some, but not all, respondents observed or made changes to their apheresis service during the COVID-19 pandemic. A subset of changes, such as increased utilization of telemedicine, may persist.

Use of an in-house trypsin-based method to resolve the interference of daratumumab.

BACKGROUND: Daratumumab (DARA) is a monoclonal antibody for treatment of plasma cell myeloma targeting CD38, a surface molecule expressed on plasma cells and red blood cells (RBCs). This complicates blood bank testing, requiring dithiothreitol (DTT) to remove DARA interference. A simple in-house method of removing DARA interference without use of DTT, a potentially hazardous chemical, is desirable. We demonstrate a trypsin-based method to remove interference in antibody testing at a medical center (MC), with parallel testing at an immunohematology reference laboratory (IRL). STUDY DESIGN AND METHODS: Pre-DARA type and screen (T&S) samples were obtained from 61 patients for antibody testing and RBC phenotyping using untreated reagent RBCs. Subsequent post-DARA T&S testing was performed with untreated reagent RBCs to demonstrate interference and repeated after trypsin treatment. Positive trypsin-treated antibody screens were reflexed to antibody identification using trypsin-treated panel cells. Parallel testing was performed on the same post-DARA samples at IRL. RESULTS: DARA interference was detected in 61/61 (100%) samples by MC and IRL. After trypsin treatment, DARA interference was eliminated in 60/61 (98.4%) antibody screens by both institutions with an overall percent agreement of 96.7% (95% confidence interval [CI] 88.7%-99.6%). Identification of known alloantibodies was confirmed in 3/3 patients with 100% concordant results between MC and IRL. There were no false-negative results demonstrated by IRL's functionally CD38-negative controls. CONCLUSION: Our in-house trypsin-based method enables pretransfusion testing of patients receiving DARA in an accurate and cost-effective manner without missing clinically significant alloantibodies. This presents an additional testing option where DTT use is undesirable.

Comparison of SARS-CoV-2 detection from nasopharyngeal swab samples by the Roche cobas 6800 SARS-CoV-2 test and a laboratory-developed real-time RT-PCR test.

The urgent need to implement and rapidly expand testing for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has led to the development of multiple assays. How these tests perform relative to one another is poorly understood. We evaluated the concordance between the Roche Diagnostics cobas 6800 SARS-CoV-2 test and a laboratory-developed test (LDT) real-time reverse transcription-polymerase chain reaction based on a modified Centers for Disease Control and Prevention protocol, for the detection of SARS-CoV-2 in samples submitted to the Clinical Laboratories of the Mount Sinai Health System. A total of 1006 nasopharyngeal swabs in universal transport medium from persons under investigation were tested for SARS-CoV-2 as part of routine clinical care using the cobas SARS-CoV-2 test with subsequent evaluation by the LDT. Cycle threshold values were analyzed and interpreted as either positive ("detected" or "presumptive positive"), negative (not detected), inconclusive, or invalid. Statistical analysis was performed using GraphPad Prism 8. The cobas SARS-CoV-2 test reported 706 positive and 300 negative results. The LDT reported 640 positive, 323 negative, 34 inconclusive, and 9 invalid results. When excluding inconclusive and invalid results, the overall percent agreement between the two platforms was 95.8%. Cohen's κ coefficient was 0.904 (95% confidence interval, 0.875-0.933), suggesting almost perfect agreement between both platforms. An overall discordance rate of 4.2% between the two systems may reflect differences in primer sequences, assay limit of detection, or other factors, highlighting the importance of comparing the performance of different testing platforms.