A meta-analysis on existing data on the use of autologous stem cell transplant (ASCT) in older patients with newly diagnosed multiple myeloma confirmed the need for randomized controlled trials looking into the role of transplant in this patient population.
A review of six observational studies and two randomized controlled trials showed that ASCT may improve overall survival and complete response rates in patients age 65 years or older with newly diagnosed disease, but the quality of available evidence is low.
“This systematic review represents an important step in highlighting the knowledge and evidence gaps in the role of ASCT in this cohort,” wrote study researcher Hira Mian, MD, of McMaster University in Hamilton, Canada, and colleagues, in the Journal of Geriatric Oncology. “We believe that larger well-conducted studies that directly compare ASCT vs non-ASCT approaches will help improve our understanding of the role of ASCT in older adults with myeloma.”
According to the study, the role of ASCT in patients age 65 and older is controversial. Observational studies have shown comparable outcomes for older patients undergoing transplant as those seen in younger patients, but randomized clinical trials in older patients have had conflicting results.
“Nevertheless, the numbers of ASCT being conducted in older patients is steadily increasing in both North America and Europe based upon retrospective registry data, which show similar progression-free survival and toxicity risk as in younger patients,” Mian and colleagues wrote.
In this analysis, they reviewed observational studies (642 patients undergoing transplant) and randomized controlled trials (170 patients undergoing transplant), the majority of which were conducted from 2000 to 2010, to assess efficacy and toxicity of ASCT in older patients with myeloma.
Pooled overall survival and progression-free survival data from the two randomized trials did not favor the ASCT or non-ASCT approach over the other. There were insufficient data reporting in the randomized trials to pool outcomes on complete response rate.
Pooled data from the observational studies did show an advantage to ASCT (hazard ratio, 0.44; 95% CI, 0.34–0.58; P < .001) in terms of overall survival, but conclusions could not be drawn about progression-free survival. There was also an improvement in response rate for ASCT seen in the pooled data from observational trials (odds ratio, 5.06; 95% CI, 2.60–9.88; P < .001).
Toxicity data were insufficient for pooled analyses.
“The overall evidence from observational studies for both improvement in overall survival and complete response rate with ASCT was of very low quality,” the researchers wrote. “Risk of bias mainly due to confounding factors present in observational studies is one important source for this low quality of evidence. Overall, as expected, there were younger and more ‘fit’ patients in the ASCT arm, which may have contributed to the improved overall survival and complete response rates seen in this cohort.”