Weiss, Matthias

Abstract Background Reference sets are needed to evaluate performance of multi-cancer detection (MCD) assays. The National Cancer Institute funded the Alliance reference set study to assess MCDs for use in future trials. Methods Individuals with cancer and controls were recruited; blood specimens were collected prior to cancer treatment. A performance evaluation study was designed utilizing reference set samples. Companies (n = 6) were selected to participate based on review of performance data and ability to utilize the blood collection tube. Companies received samples from cancer types their assay was designed to detect (“targeted”), plus additional “non-targeted” and control samples. Companies reported positive/negative calls, risk scores, and tissue-of-origin (TOO) predictions. Sensitivity was computed for early (I-II) and late (III-IV) stage cases, based on positive/negative calls (SEPN) and at fixed 98% specificity (SE98). Specificity and TOO accuracy were computed. Results Five hundred and forty nine cases (encompassing 13 cancer types) and 413 controls from the reference set were included in the study. Companies assessed samples from median 6 (range 5-9) targeted cancer types and median 8 (range: 7-11) overall cancer types. Median (range) specificity was 92.3% (76.5%-98.5%). Median (range) SEPN was 32% (25%-42%) for early stage and 73% (48%-89%) for late stage; while median (range) SE98 was 19% (8%-35%) for early stage and 66% (13%-79%) for late stage. Median sensitivity for non-targeted types was 40% (early stage) and 52% (late stage). Median (range) TOO accuracy (primary predicted site) was 75% (64%-78%). Conclusions Sensitivity and specificity varied widely across assays with early-stage sensitivity substantially lower than late-stage sensitivity. Clinical Trial Registration Number ClinicalTrials.gov identifier NCT05334069.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. In 2003, the Eastern Cooperative Oncology Group initiated a randomized phase III clinical trial (E4402) comparing two different rituximab dosing strategies for patients with previously untreated low–tumor burden follicular lymphoma. Rituximab-responsive patients (n = 299) were randomly assigned to either a retreatment rituximab (RR) strategy or a maintenance rituximab (MR) strategy. Each dosing strategy was continued until treatment failure. The primary end point of the study was time to treatment failure (TTF). In the original report, there was no difference in TTF between the two dosing strategies. Here, we report on the long-term outcomes for secondary end points of time to first cytotoxic therapy, duration of response, and overall survival (OS). At 7 years, 83% of MR patients had not required first chemotherapy compared with 63% of RR patients (hazard ratio, 2.37 [95% CI, 1.5 to 3.76]). At 7 years, 71% of MR remained in their first remission compared with 37% of RR patients. Despite the improved first remission length with MR, there was no difference in OS at 10 years (83% v 84%). With mature long-term data, we confirm that prolonged maintenance rituximab does not confer an OS advantage in low–tumor burden follicular lymphoma.