Report on the ISBTC mini-symposium on biologic effects of targeted therapeutics

Correlation of pretransplant and early post-transplant response assessment with outcomes after reduced-intensity allogeneic hematopoietic stem cell transplantation for non-Hodgkin's lymphoma

BACKGROUND

Chemotherapy sensitivity, defined simply as at least a partial response to chemotherapy, is an important outcome predictor for non-Hodgkin lymphoma (NHL) patients undergoing reduced-intensity allogeneic hematopoietic stem cell transplantation (allo-HCT). The authors hypothesized that further differentiation of chemotherapy sensitivity by specific response, complete remission (CR) versus partial remission (PR) versus stable disease (SD) versus progression of disease (PD), correlates with post-transplant outcomes.

METHODS

The impact of pretransplant and early (28 days) post-transplant disease response on transplant outcomes was analyzed in 63 NHL patients treated with reduced-intensity allo-HCT.

RESULTS

The 3-year event-free survival (EFS) and overall survival (OS) (median potential follow-up after reduced-intensity allo-HCT = 58 months) for all patients was 37% and 47%, respectively. The 3-year EFS based on pretransplant response was: CR = 50%; PR = 66%; SD = 18%; no patient with PD pretransplant reached 3-year follow-up. The 3-year OS based on pretransplant response was: CR = 63%; PR = 69%; SD = 45%. The 3-year EFS based on post-transplant response was: CR = 57%; PR = 32%; SD = 33%; no patient with PD post-transplant reached 3-year follow-up. The 3-year OS based on post-transplant response was: CR = 65%; PR = 43%; SD = 50%. In multivariate analyses, pretransplant response was the best predictor of EFS (P < .0001). Pretransplant response (P < .0001) and age (P = .0035) were jointly associated with OS.

CONCLUSIONS

These data suggest that NHL patients with pretransplant SD, generally considered inappropriate candidates, may benefit from reduced-intensity allo-HCT, and patients with pretransplant PD should only receive this therapy in clinical trials.

Identification of immunologic biomarkers associated with clinical response after immune-based therapy for cancer

The identification of immunologic biomarkers associated with clinical response after immune intervention for cancer is an area of intensive investigation. The field would benefit from a more systemic and directed approach for biomarker identification and evaluation. Lessons can be learned from other fields, such as cancer diagnostics, as to how to develop response-associated biomarkers. Studies in both human in vitro models as well as murine models of cancer can significantly inform and streamline the choice of candidates. Adoptive T-cell therapy is an interesting model for exploring potential immunologic surrogates that may predict clinical response. Most likely the clinical effectiveness of immune-based treatments will be predicted by panels of markers rather than single assays of a specific immune effector cell.