Early use of FDG-PET imaging after CAR-T therapy in patients with large B-cell lymphoma may predict the risk of treatment failure and could be used to guide management decisions, a UK study has concluded.
Analysis of 171 patients treated with CAR-T found that use of the five-point Deauville score (DS) was significantly associated with “durability of response”.
Writing in Blood Advances, the researchers who looked at imaging one and three months after CAR-T said while patients with early DS1-2 remission showed excellent long-term outcomes, patients with DS3-4 response had a 31% risk of early relapse and those with DS4 had 46% risk of early relapse when excluding cases with activity related to radiotherapy.
The DS5 response was associated with “dismal outcomes” and should be regarded as treatment failure, they concluded.
All patients with DS5 by one month progressed by month three, the analysis showed.
“Classifying these patients as ‘responders’ raises unrealistic expectations and treatment decisions should not be deferred until formal confirmation of progressive disease, particularly if the disease is amenable to radiotherapy,” they said.
Future trials could look at whether additional treatment can be guided by early signs on the five-point score – for example DS1-2 patients being spared the toxicity of more treatment but DS3-4 patients who have a 30-45% risk of early CAR-T failure might benefit from combination treatment with immunomodulatory agents, they suggested.
“Our results indicate that early FDG PET response using Deauville criteria may be used to predict the risk of CAR-T failure and to guide post-CAR-T management in large B-cell lymphoma,” they concluded.
Dr Graham Collins, Consultant Haematologist and Lymphoma Lead at Oxford University Hospitals NHS Foundation Trust said CAR-T was now the standard of care in the UK in relapsed refractory B cell lymphoma and “probably a third of patients are cured”.
“But probably 50-60% still relapse and this is very aggressive so they relapse quickly,” he added noting that further treatment at that point could be challenging because of how ill they are.
“The nice thing about the Deauville score is that it’s very reproducible. What this does now is helps with follow up so if someone has a DS4 you would be more likely to see them more frequently in clinic and it could possibly lead you to change their treatment.
“What this might do eventually – and we’re not there yet – is by identifying that high risk group that might lead you to some other intervention but ultimately that would be in the context of a clinical trial.”