Reeder, Craig B.

AbstractWaldenström macroglobulinemia (WM) is an immunoglobulin M‐associated lymphoma, with majority of cases demonstrating MYD88 locus alteration, most commonly, MYD88L265P. Owing to low prevalence of the wild‐type (WT) MYD88 genotype in WM, clinically relevant data in this patient population are sparse, with one study showing nearly a 10‐fold increased risk of mortality in this subgroup compared to patients with MYD88L265P mutation. We studied a large cohort of patients with MYD88L265P and MYD88WT WM, evaluated at Mayo Clinic, Rochester, between 1995 and 2016, to specifically assess the impact of these genotypes on clinical course. Of 557 patients, MYD88L265P mutation status, as determined by allele‐specific polymerase chain reaction, was known in 219, and 174 (79%) of those exhibited MYD88L265P, 157 of 174 patients had active disease. Of 45 (21%) patients with MYD88WT genotype, 44 had active disease. The estimated median follow‐up was 7.0 years; median overall survival was 10.2 years (95% CI: 8.4‐16.5) for MYD88L265P versus 13.9 years (95% CI: 6.4‐29.3) for the MYD88WT (P = 0.86). The time‐to‐next therapy from frontline treatment and the presenting features were similar in the two patient populations. For patients with smoldering WM at diagnosis, the median time‐to‐progression to active disease was 2.8 years (95% CI: 2.2‐3.8) in the MYD88L265P cohort and 1.9 years (95% CI: 0.7‐3.1) in the MYD88WT cohort (P = 0.21). The frequency of transformation to high‐grade lymphoma, or the development of therapy‐elated myelodysplastic syndrome was higher in the MYD88WT cohort (16% versus 4% in the MYD88L265P, P = 0.009). In conclusion, MYD88L265P mutation does not appear to be a determinant of outcome, and its presence may not be a disease‐defining feature in WM. Our findings warrant external validation, preferably through prospective studies.

Key Points Ibrutinib has modest activity in FL with low response rates in rituximab-refractory patients. CARD11 mutations predict for lack of response to ibrutinib.

SummaryThe management of Waldenström macroglobulinaemia (WM) relies predominantly on small trials, one of which has demonstrated activity of dexamethasone, rituximab and cyclophosphamide (DRC) in the frontline setting. We report on the efficacy of DRC, focusing on relapsed/refractory (R/R) patients. Ibrutinib, a recently approved agent in WM demonstrated limited activity in patients with MYD88WT genotype. Herein, we additionally report on the activity of DRC based on the MYD88L265P mutation status. Of 100 WM patients evaluated between January 2007 and December 2014 who received DRC, 50 had R/R WM. The overall response rate (ORR) was 87%. The median progression‐free survival (PFS) and time‐to‐next‐therapy (TTNT) were 32 (95% confidence interval [CI]: 15–51) and 50 (95% CI: 35–60) months, respectively. In the previously untreated cohort (n = 50), the ORR was 96%, and the median PFS and TTNT were 34 months (95% CI: 23–not reached [NR]) and NR (95% CI: 37–NR), respectively. Twenty‐five (86%) of 29 genotyped patients harbored MYD88L265P. The response rates and outcomes were independent of MYD88 mutation status. Grade ≥3 adverse effects included neutropenia (20%), thrombocytopenia (7%) and infections (3%). Similar to the frontline setting, DRC is an effective and well‐tolerated salvage regimen for WM. In contrast to ibrutinib, DRC offers a less expensive, fixed‐duration option, with preliminary data suggesting efficacy independent of the patients’ MYD88 status.

Key Points PVD is an active combination in relapsed lenalidomide-refractory MM patients. PVD with weekly bortezomib offers a simpler, more convenient, and well-tolerated regimen option.

Akt is a downstream target of B cell receptor signaling and is a central regulator of CLL cell survival. We aim to investigate the safety and efficacy of the Akt inhibitor MK‐2206 in combination with bendamustine and rituximab (BR) in relapsed and/or refractory CLL in a phase I/II study. A standard phase I design was used with cohorts of three plus three patients to determine the maximum tolerated dose (MTD) of MK‐2206 in combination with BR in relapsed CLL. Single‐agent MK‐2206 (weekly dosed) was administered one‐week in advance before BR on cycle 1 and subsequently was given with BR at the same time for cycle 2‐6. Phase II employed the MTD of MK‐2206 with BR to evaluate safety and efficacy of this study combination. Thirteen relapsed/refractory CLL were treated for maximal 6‐cycle of therapy. The maximum tolerated dose of MK‐2206 was 90 mg by mouth once weekly. The most common grade 3/4 adverse events were neutropenia (46%), febrile neutropenia (23%), rash (15%), diarrhea (15%), and thrombocytopenia (15%). Overall response rate was 92% with a median progression free survival and treatment free survival of 16 and 24 months, respectively. Five patients (38%) achieved complete remission or complete remission with incomplete count recovery, two of whom were MRD negative. The efficacy and tolerability of this combination indicates that Akt inhibition combined with chemoimmunotherapy is a promising novel treatment combination in CLL and deserves further prospective clinical trial.

AbstractPatients with indolent non‐Hodgkin lymphoma (NHL) have multiple treatment options yet there is no consensus as to the best initial therapy. Lenalidomide, an immunomodulatory agent, has single agent activity in relapsed lymphoma. This trial was conducted to assess feasibility, efficacy, and safety of adding lenalidomide to rituximab, cyclophosphamide, and dexamethasone (LR‐CD) in untreated indolent NHL patients requiring therapy. This was a single institution phase II trial. Treatment consisted of IV rituximab 375 mg/m2 day 1; oral lenalidomide 20 mg days 1–21; cyclophosphamide 250 mg/m2 days 1, 8, and 15; and dexamethasone 40 mg days 1, 8, 15, and 22 of a 28‐day cycle. Treatment continued 2 cycles beyond best response for a maximum of 12 cycles without rituximab maintenance. Thirty‐three patients were treated. Median age was 68 (43–83 years). 39% had stage IV disease. Histologic subtypes included 8 follicular lymphoma (FL), 7 marginal zone lymphoma (MZL) (1 splenic, 2 extranodal, and 4 nodal), 15 Waldenström's macroglobulinemia (WM), 1 lymphoplasmacytic lymphoma, 1 small lymphocytic lymphoma, and 1 low‐grade B‐cell lymphoma with plasmacytic differentiation (unable to be classified better as MZL or LPL). Hematologic toxicity was the most common adverse event. Median time of follow‐up was 23.4 months (range 1.8–50.9). The overall response rate was 87.9%, with 30.3% complete response. The median duration of response was 38.7 months. The median progression free survival was 39.7 months, while median overall survival (OS) has not yet been reached. Lenalidomide can be safely added to a simple regimen of rituximab, oral cyclophosphamide, and dexamethasone and is an effective combination as initial therapy for low‐grade B‐cell NHL.

AbstractRelapsed indolent lymphoma often becomes refractory to standard chemoimmunotherapy and requires new therapeutic strategies. Targeting the PI3K/mTOR pathway in several types of lymphoma has shown preclinical and clinical efficacy providing the rationale to test this strategy in the treatment of relapsed/refractory indolent lymphomas. We investigated in a phase II open label clinical trial the efficacy and safety of single agent everolimus, an inhibitor of mTORC1, in patients with relapsed/refractory indolent lymphomas. Eligible patients received oral everolimus 10 mg daily on a 28 day‐cycle schedule. The primary endpoint was to evaluate the overall response rate (ORR) and safety of single‐agent everolimus in this patient population. Fifty‐five patients with indolent lymphoma were accrued. The median age was 67 years (range: 33‐85) with a median of five prior therapies (range: 1‐10). The ORR was 35% (19/55; 95% CI: 24‐48%), with complete response unconfirmed in 4% (2/55), and partial response in 31% (17/55). The ORR was 61% (14/23) in the patients with FL. The median time to response was 2.3 months (range: 1.4‐14.1), median duration of response of 11.5 months (95%‐CI: 5.7‐30.4), and a median progression‐free survival of 7.2 months (95%‐CI: 5.5‐12.5). The most common toxicity was hematologic with grades 3‐4 anemia, neutropenia, and thrombocytopenia documented in 15% (8/55), 22% (12/55), and 33% (18/55), respectively. There were no cases of febrile neutropenia, and eight patients discontinued therapy because of adverse events. Everolimus monotherapy is a valid therapeutic option in the relapsed and/or refractory indolent non‐Hodgkin lymphoma patients and is well tolerated.

Key Points The combination of ixazomib and dexamethasone has clinical activity in patients with relapsed and or refractory multiple myeloma. Higher dose of ixazomib leads to improved response rates but with higher rates of treatment related adverse events.