Activity of bortezomib in MALT lymphomas: A IELSG phase II study

The International Extranodal Lymphoma Study Group (IELSG) is coordinating a phase II trial aimed to assess the antitumor activity and safety of bortezomib in patients (pts) with relapsed or refractory extranodal marginal zone B-cell lymphoma of MALT-type. Bortezomib 1.3 mg/m 2 is administered on days 1, 4, 8, and 11 of a 21-day cycle, for up to 6 cycles. Response and progression are determined by International Workshop Criteria. As of January 2008, 25 pts have been enrolled in the study: among the 21 pts in whom the data are available, 12 (57%) patients were male, median age was 63 years (range, 38–81). At time of enrolment, the Ann Arbor stages distribution was the following: stage I=5 pts (24%), stage II=5 pts (24%), stage IV=11 (52%). In 11 pts primary gastric localization was present, in 5 cases primary skin, in 2 cases primary subcutaneous, moreover a primary lung, orbit, muscle localization was reported in 1 pt each. All patients had ECOG PS=0; in 3 cases (14%) elevated serum LDH was reported. More than 1 site of extranodal localization was present in 5 pts (24%). Median number of prior therapies was 2 (range, 1–3). Median follow-up was 17 months. Eleven pts were assessed for response at the end of treatment plan: 3 pts had a CR (27%); 4 a PR (37%) and 3 SD (27%) and 1 a PD (9%). Four additional pts, with ongoing therapies, have been evaluated after the first two courses of therapy: one pt achieved a CR, 1 pt a PR, 1 pt a SD and in 1 a PD was observed. Significant duration of response was observed among the 4 pts in CR, ranging from 18 to 22 months and in most cases still ongoing. The safety profile of bortezomib is similar to that observed in multiple myeloma and other subtypes of non-Hodgkin lymphoma. The most relevant grade 3 or higher adverse events were peripheral neuropathy and fatigue. Three deaths, non-related to treatment, were observed during the early follow up. These preliminary results suggest that bortezomib is active and safe in relapsed or refractory MALT lymphomas and encourage us to complete the studies accrual. Disclosure: Research Funding: Johnson & Johnson partially supported the trial.