Erica N Boswell

Results of a phase 2 trial of the single-agent histone deacetylase inhibitor panobinostat in patients with relapsed/refractory Waldenström macroglobulinemia

The present study aimed to determine the safety and activity of the histone deacetylase inhibitor panobinostat in patients with relapsed/refractory Waldenström macroglobulinemia (WM). Eligibility criteria included patients with relapsed/refractory WM with any number of prior therapies. Patients received panobinostat at 30 mg 3 times a week; 12 of 36 (33%) patients were enrolled at 25 mg dose. A total of 36 patients received therapy. The median age was 62 years (range, 47-80) and the median number of prior therapies was 3 (range, 1-8). All of the patients had received prior rituximab. Minimal response (MR) or better was achieved in 47% of patients (90% confidence interval [CI], 33-62), with 22% partial remissions and 25% MR. In addition, 18 (50%) patients achieved stable disease and none showed progression while on therapy. The median time to first response was 1.8 months (range, 1.7-3.2). The median progression-free survival was 6.6 months(90% CI, 5.5-14.8). Grade 3 and 4 toxicities included thrombocytopenia (67%), neutropenia (36%), anemia (28%), leukopenia (22%), and fatigue (11%). We conclude that panobinostat is an active therapeutic agent in patients with relapsed/ refractory WM. This study (www.clinicaltrials.gov identifier: NCT00936611) establishes a role for histone deacetylase inhibitors as an active class of therapeutic agents in WM.

Drug-Related Pneumonitis During Mammalian Target of Rapamycin Inhibitor Therapy: Radiographic Pattern-Based Approach in Waldenström Macroglobulinemia as a Paradigm

BACKGROUND This study determined the frequency of drug-related pneumonitis during mammalian target of rapamycin (mTOR) inhibitor therapy in Waldenström macroglobulinemia patients and investigated the imaging characteristics and radiographic patterns of pneumonitis. MATERIALS AND METHODS A total of 40 patients (23 men, 17 women; 43-84 years old) with Waldenström macroglobulinemia treated in 2 trials of the mTOR inhibitor everolimus were retrospectively studied. Chest computed tomography (CT) scans during therapy were reviewed for abnormalities suspicious for drug-related pneumonitis by the consensus of three radiologists, evaluating the extent, distributions, and specific findings. The radiographic patterns of pneumonitis were classified using the American Thoracic Society/European Respiratory Society classification of interstitial pneumonia. RESULTS Drug-related pneumonitis was noted in 23 patients (58%). The median time from the initiation of therapy to the onset of pneumonitis was 5.7 months. Lower lungs were involved in all 23 patients, with a higher extent than in the other zones (p < .001). The distribution was peripheral and lower in 11 patients (48%) and mixed and multifocal in 10 (44%). The findings were bilateral in 20 patients (87%). Ground glass opacities (GGOs) and reticular opacities were present in all 23 patients, with consolidation in 12, traction bronchiectasis in 2, and centrilobular nodularity in 1. The pattern of pneumonitis was classified as cryptogenic organizing pneumonia (COP) in 16 (70%) and nonspecific interstitial pneumonia (NSIP) in 7 (30%), with overlapping features of COP and NSIP in 7 patients. CONCLUSION Drug-related pneumonitis was noted on CT in 58% of Waldenström macroglobulinemia patients treated with mTOR inhibitor therapy. Most common findings were bilateral GGOs and reticular opacities, with or without consolidation, in peripheral and lower lungs, demonstrating COP and NSIP patterns. IMPLICATIONS FOR PRACTICE The present study has demonstrated that drug-related pneumonitis during mammalian target of rapamycin (mTOR) inhibitor therapy is highly frequent, occurring in 58% of patients with Waldenström macroglobulinemia. The radiographic patterns of pneumonitis demonstrated cryptogenic organizing pneumonia and nonspecific interstitial pneumonia patterns, with overlapping features in 30% of the patients. The present study describes an initial attempt of a radiographic pattern-based approach to drug-related pneumonitis in the era of molecular targeting therapy, with a cohort of patients with Waldenström macroglobulinemia receiving mTOR inhibitor therapy as a paradigm, which might contribute to further understanding and in-depth interpretation of lung toxicity during novel cancer therapy.

Phase I/II trial of everolimus in combination with bortezomib and rituximab (RVR) in relapsed/refractory Waldenstrom macroglobulinemia

We examined the combination of the mammalian target of rapamycin inhibitor everolimus with bortezomib and rituximab in patients with relapsed/refractory Waldenstrom macroglobulinemia (WM) in a phase I/II study. All patients received six cycles of the combination of everolimus/rituximab or everolimus/bortezomib/rituximab followed by maintenance with everolimus until progression. Forty-six patients were treated; 98% received prior rituximab and 57% received prior bortezomib. No dose-limiting toxicities were observed in the phase I. The most common treatment-related toxicities of all grades were fatigue (63%), anemia (54%), leucopenia (52%), neutropenia (48%) and diarrhea (43%). Thirty-six (78%) of the 46 patients received full dose therapy (FDT) of the three drugs. Of these 36, 2 (6%) had complete response (90% confidence interval (CI): 1–16). In all, 32/36 (89%) of patients experienced at least a minimal response (90% CI: 76–96%). The observed partial response or better response rate was 19/36 (53, 90 CI: 38–67%). For the 36 FDT patients, the median progression-free survival was 21 months (95% CI: 12–not estimable). In summary, this study demonstrates that the combination of everolimus, bortezomib and rituximab is well tolerated and achieved 89% response rate even in patients previously treated, making it a possible model of non-chemotherapeutic-based combination therapy in WM.