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PET-CT Status After First Line Immunochemotherapy Prognostic for Survival in FL
Achieving a positron emission tomography-computed tomography (PET-CT) complete metabolic response (CMR) after first line immunochemotherapy is strongly associated with improved survival outcomes in follicular lymphoma (FL), according to 6-year follow-up data from the GALLIUM study, presented at the virtual 2020 EHA Annual Congress.
“The prognostic value of 18F-fluorodeoxyglucose (FDG)… [PET-CT] response assessment following first-line immunochemotherapy for advanced-stage symptomatic… [FL] was previously demonstrated for patients enrolled in the phase 3 GALLIUM study,” wrote Prof Judith Trotman, MBChB, FRACP, FRCPA, Concord Repatriation General Hospital, University of Sydney, Australia, and colleagues.
This long-term follow-up analysis aimed to evaluate the association between PET-CT CMR with survival in previously untreated FL.
The GALLIUM study randomized 1202 patients to induction therapy with obinutuzumab (1000 mg on days 1, 8, and 15 of cycle 1 and then on day 1 each cycle thereafter) or rituximab (375 mg/m2 on day 1 of each cycle) in combination with chemotherapy.
PET-CT scans were mandatory at baseline and end-of-induction for the first 170 patients enrolled in the trial and optional thereafter. Lugano 2014 criteria were applied by an independent review committee (IRC) for this response analysis.
Dr Trotman and colleagues evaluated the association between end-of-induction PET CMR status and progression-free survival (PFS) and overall survival (OS). Patients who had progressive disease before or at end-of-induction were excluded from the PFS analysis and patients who died before end-of-induction were excluded from both the PFS and OS analyses.
Overall 609 patients had a baseline PET scan, 595 (98%) with detectable lesions. Of these patients, 519 had an end-of-induction PET evaluable by Lugano 2014 criteria.
A total of 450 (76%) patients had achieved CMR at end-of-induction per IRC assessment. After a median follow-up of 76.5 months, end-of-induction PET CMR was highly prognostic for both PFS and OS. The 6-year investigator-assessed PFS from end-of-induction was 62.6% (95% CI: 57.0–67.6) for patients who achieved CMR compared with 23.4% (95% CI: 12.2–36.7) for those who did not. OS was 91.3% (95% CI: 88.1–93.6) versus 79.6% (95% CI: 68.0–87.4), respectively.
“With more than 6 years of follow-up, this analysis confirms that after first-line chemoimmunotherapy for FL, achieving CMR on PET-CT is an early and strong predictor of increased PFS and OS,” Dr Trotman and colleagues concluded.—Janelle Bradley
Trotman J, Barrington SF, Meignan M, et al. First-Line Immunochemotherapy for Follicular Lymphoma in the GALLIUM Study: Prognostic Value of PET-CT Status After Long-Term Follow-Up. Presented at: the Virtual 2020 EHA Annual Congress; June 11-21, 2020. Abstract EP1158.
