A Single Center Review Evaluating Daratumumab Outcomes in Multiple Myeloma Patients at Monter Cancer Center/Northwell Health Cancer Institute
Authors: Chen Chung H , Lee Chung-Shien , Ahmad Samrah , Hartley-Brown Monique 
Published: November 2020

Multiple myeloma (MM) is a malignant neoplasm of plasma cells in bone marrow. Daratumumab (Dara) is a CD38-directed antibody which is Food and Drug Administration (FDA) approved for treatment of patients with MM. Dara is recommended by the National Comprehensive Cancer Network (NCCN) guidelines, which many community oncologist use as the standard of care guidelines. Therefore, we consider it important to analyze Dara use and effects in the real-world community Oncology clinic setting. We evaluated the survival outcomes, both progression-free survival (PFS) and overall survival (OS), as well as the time to progression (TTP) of MM and common adverse events (ADEs) seen in patients at a single site, Monter Cancer Center in the Northwell Health (NH) system.
This is a single group study evaluating outcomes of patients with MM who received Dara at NH. Primary objectives include evaluating OS, defined as time from initiating Dara therapy to time of death from any cause. Secondary objectives include PFS, time from initiation of Dara therapy to documented disease progression. We also plan to evaluate time to next treatment (TTNT), TTP and rate of ADEs within 30 days of initiating Dara.
This is a retrospective study of patients with MM who received Dara at Monter Cancer Center, Northwell Health Cancer Institute. Basic demographics; gender, age at diagnosis, body mass index (BMI), and ethnicity, were collected. Treatment information collected included, previous number of therapies, dose of Dara in total and per body weight in kg, number of doses of Dara received. Data was collected using electronic medical records from January 2015 through December 2019. Patient charts were reviewed, collecting data from the time of diagnosis and initiation of Dara to date of last known follow-up, or death. Progression of disease information and initiation of new therapy was collected during this time frame. Standard methods of survival analysis were used to analyze the primary objectives. Kaplan-Meier estimate was used to analyze PFS and OS at 6, 12, 24, and 36 months. TTNT was defined as length of time from the date of initiation of Dara to the date the patient was started on a new therapeutic regimen. TTP was defined as the date the patient started Dara therapy to the date of documentation of disease progression or relapse. Cumulative incidence rates were calculated to determine the rates of incidence of next treatment in the presence of competing risk of death, and rate of ADEs in patients during this time frame. Rate of ADEs were reported with corresponding 95% confidence intervals using a binomial confidence interval.
A total of 50 patients were included in the analysis. Baseline demographics are in line with published data, mean age was 68.8 years, with a non-Caucasian predominance of 68% to 32% Caucasian. The gender profile was 42% male. Prior mean number of therapies was 2.9, with a median of 2. Dose of Dara used was in line with the recommended dosing with mean 16.3mg/kg dosing. The mean number of doses received were 17. Similar to prior published data the predominant heavy chain MM phenotype was IgG at 48%.
The OS, at 36 months was 54%, where 23 patients (46%) had documented date of death during the 5-year time span reviewed. Thirty-one patients (62%) experienced disease progression (TTP), ranging from 28 to 1047 days from start of Dara treatment, with a median TTP of 317 days. The median PFS was 436 days (95% CI: 334-676 days). There were 46% patients that continued on another line of therapy post Dara , with the TTNT ranging from 25 to 541 days, median 175 days from initial Dara therapy. Among patients who had at least one adverse event, the most frequently occurring pattern was fatigue, pyrexia, and chills at 22%, followed by infusion related reactions at 20%.
Dara has shown strong clinical efficacy clinical trials. The patients in clinical trials are often not reflective of real-world clinical patients. This study evaluates patients at a single cancer center in the NH system. The data reinforces the efficacy and tolerability of Dara in the real-world setting. It also depicts the difference in OS, PFS, TTP, TTNT and ADEs in the real-world setting. The data suggests Dara outcomes in community-based oncology centers vary from clinical trial data. However, it does indicate similar improved benefits in OS, PFS and TTNT compared with other retrospective studies at other centers. Further prospective studies would be beneficial in evaluating this real-world impact.

Disclosures
No relevant conflicts of interest to declare.