Patients with multiple myeloma who were obese or overweight had a trend toward slightly improved progression-free survival and overall survival outcomes compared to patients who had a normal weight, according to data from an exploratory analysis.
Patients with multiple myeloma who were obese or overweight had a trend toward slightly improved progression-free survival and overall survival outcomes compared to patients who had a normal weight, according to data from an exploratory analysis presented at the 2020 ASCO Virtual Scientific Program.
“Obesity has been implicated as a risk factor for the development of certain types of cancers, including multiple myeloma,” Dr. Rachel Ershler, a medical officer at the Food and Drug Administration (FDA), said during a presentation of the data. “Previous studies in other tumor types suggest that overweight subjects may have better outcomes. However, in relapsed refractory multiple myeloma, it is unknown whether body weight affects outcomes to therapy.”
Ershler and colleagues conducted a retrospective analysis of 13 clinical trials, comprising 5,898 patients (with a median age of 65 years) with relapsed or refractory multiple myeloma, that were submitted to the FDA between 2012 and 2018. The researchers then divided the patients into four different groups based on their body mass index (BMI): underweight (BMI <18.5 kg/m2), normal weight (BMI 18.5 - <25 kg/m2), overweight (BMI 25 - <30 kg/m2) and obese (BMI >30 kg/m2).
Measuring progression-free survival (PFS), or the time from the start of treatment until disease worsened, and overall survival (OS) were the main goals of multivariate analysis.
Thirty-eight percent of the patients in the analysis were overweight, 31% had a normal weight, 23% were obese, 7% did not have available data and 1.5% were underweight. More of the patients who were overweight (63%) and obese (55%) were male, whereas more patients who were underweight (75%) were female.
Patients who were underweight or had a normal weight had a median PFS of 13 months compared to 15 months in patients who were overweight or obese. The median overall survival varied slightly between patients who were obese (44 months), overweight (42 months) and had a normal weight (41 months). However, patients who were underweight had a significantly shorter median overall survival of 34 months.
Ershler noted that the results of this analysis are similar to previous studies in other malignancies.
“In this exploratory analysis of patients with relapsed/refractory multiple myeloma, patients who were overweight and obese had a trend towards slightly improved PFS and OS when compared to normal weight patients,” she said. “Similar trends were observed in the analyses of overall response rate and BMI.”
Ershler concluded by acknowledging that there were some limitations to the analysis, including the relatively small sample of patients in the underweight category and the heterogeneity in treatment regimens used among the clinical trials that were a part of the analysis.
“Future studies are needed to evaluate safety and the impact of treatment regimens on efficacy outcome measures based on body weight in this relapsed refractory patient population,” she said.
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