Preliminary results
This research is ongoing, so it’s too early to announce any discoveries, but the study is moving along as planned.
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“The preliminary data we have so far are demonstrating the validity of the study,” Dr. Cole said. “Things are going well. We’re able to do the cognitive testing and collect the samples that we need and ship them without losing the integrity of the samples.”
Dr. Sands noted that enrollment has been encouraging. As this is a substudy of DFCI-16-001, the researchers must obtain consent separately from the main study. Dr. Sands said about 89% of parents involved in the main study have agreed to enroll their children in the substudy.
Dr. Sands also said that early results from Cogstate testing have revealed patients who are experiencing cognitive decline during treatment. The researchers still have to determine if these results correlate with any biomarkers or gene variants.
Potential interventions
If the researchers can pinpoint patients at risk for cognitive deficits, the next step will be to investigate pharmacologic and behavioral interventions.
Dr. Cole said he is particularly interested in treatments that reduce oxidative stress, such as dextromethorphan and memantine. Dextromethorphan has been shown to resolve symptoms of methotrexate-induced neurotoxicity in patients (Pediatr Hematol Oncol. 2002 Jul-Aug;19[5]:319-27), and memantine reduced memory deficits in animals treated with methotrexate (Clin Cancer Res. 2013 Aug 15;19[16]:4446-54).
“Memantine hasn’t been used in kids with leukemia yet, but it’s something that I’d like to see brought to a clinical trial,” Dr. Cole said.
Dr. Sands pointed to other potential pharmacologic interventions, including the stimulants methylphenidate and modafinil. Both drugs have been shown to improve cognitive deficits in cancer survivors (J Clin Oncol. 2001 Mar 15;19[6]:1802-8; Cancer. 2009 Jun 15; 115[12]: 2605-16).
Computer-based cognitive training tools may be another option. One such tool, Lumosity, improved executive functions in a study of breast cancer survivors (Clin Breast Cancer. 2013 Aug;13[4]:299-306). Another tool, CogMed, improved working memory in survivors of brain tumors and ALL (Psychooncology. 2013 Aug; 22[8]: 1856-65).
Other behavioral interventions might include sleep hygiene and exercise. Sleep hygiene has been shown to improve cognitive function in childhood cancer survivors (Cancer. 2011 Jun 1;117[11]:2559-68), and a recent study revealed an association between exercise intolerance and negative neurocognitive outcomes in ALL survivors (Cancer. 2019 Oct 21. doi: 10.1002/cncr.32510).
“What we need to figure out is which children will respond to which interventions,” Dr. Sands said, adding that interventions will likely need to be combined.
“It’s not going to be one thing that will work for everybody,” he said. “It’s going to be: What packages of things will work for different people?”
Dr. Sands and Dr. Cole reported having no relevant financial disclosures.