A phase 2 study of weekly temsirolimus and bortezomib for relapsed or refractory B-cell non-Hodgkin lymphoma: A Wisconsin Oncology Network study

BACKGROUND Proteasome inhibitors and mammalian target of rapamycin inhibitors each have activity in various B-cell malignancies and affect distinct cellular pathways. Their combination has demonstrated synergy in vitro and in mouse models. METHODS The authors conducted a single-arm, phase 2 trial of combined temsirolimus and bortezomib in patients with relapsed and refractory B-cell non-Hodgkin lymphoma (NHL) using a dosing scheme that was previously tested in multiple myeloma. The patients received bortezomib and temsirolimus weekly on days 1, 8, 15, and 22 of a 35-day cycle. RESULTS Of 39 patients who received treatment, 3 achieved a complete response (7.7%; 95% confidence interval [CI], 1.6%-21%), and 9 had a partial response (PR) (23%; 95% CI, 11%-39%). Thus, the overall response rate (12 of 39 patients) was 31% (95% CI, 17%-48%), and the median progression-free survival was 4.7 months (95% CI, 2.1-7.8 months; 2 months for patients with diffuse large B-cell lymphoma [n = 18], 7.5 months for those with mantle cell lymphoma [n = 7], and 16.5 months for those with follicular lymphoma [n = 9]). Two extensively treated patients with diffuse large B-cell lymphoma achieved a complete response. There were no unexpected toxicities from the combination. CONCLUSIONS The current results demonstrate that the combination of a mammalian target of rapamycin inhibitor and a proteasome inhibitor is safe and has activity in patients with heavily pretreated B-cell NHL. Further studies with this combination are warranted in specific subtypes of NHL.