PI3K Inhibition Restores and Amplifies Response to Ruxolitinib in Patients with Myelofibrosis.

PURPOSE: Treatment options are limited beyond JAK inhibitors for patients with primary myelofibrosis (MF) or secondary MF. Preclinical studies have revealed that PI3Kδ inhibition cooperates with ruxolitinib, a JAK1/2 inhibitor, to reduce proliferation and induce apoptosis of JAK2V617F-mutant cell lines. PATIENTS AND METHODS: In a phase I dose-escalation and -expansion study, we evaluated the safety and efficacy of a selective PI3Kδ inhibitor, umbralisib, in combination with ruxolitinib in patients with MF who had a suboptimal response or lost response to ruxolitinib. Enrolled subjects were required to be on a stable dose of ruxolitinib for ≥8 weeks and continue that MTD at study enrollment. The recommended dose of umbralisib in combination with ruxolitinib was determined using a modified 3+3 dose-escalation design. Safety, pharmacokinetics, and efficacy outcomes were evaluated, and spleen size was measured with a novel automated digital atlas. RESULTS: Thirty-seven patients with MF (median age, 67 years) with prior exposure to ruxolitinib were enrolled. A total of 2 patients treated with 800 mg umbralisib experienced reversible grade 3 asymptomatic pancreatic enzyme elevation, but no dose-limiting toxicities were seen at lower umbralisib doses. Two patients (5%) achieved a durable complete response, and 12 patients (32%) met the International Working Group-Myeloproliferative Neoplasms Research and Treatment response criteria of clinical improvement. With a median follow-up of 50.3 months for censored patients, overall survival was greater than 70% after 3 years of follow-up. CONCLUSIONS: Adding umbralisib to ruxolitinib in patients was well tolerated and may resensitize patients with MF to ruxolitinib without unacceptable rates of adverse events seen with earlier generation PI3Kδ inhibitors. Randomized trials testing umbralisib in the treatment of MF should be pursued.

Lenalidomide vs bortezomib maintenance choice post-autologous hematopoietic cell transplantation for multiple myeloma.

Maintenance therapy post-autologous hematopoietic cell transplantation (AHCT) with either lenalidomide or bortezomib for multiple myeloma (MM) have separately been shown to improve progression-free survival (PFS), but have never been directly compared. We performed a retrospective study to investigate progression-free and overall survival outcomes and toxicities of lenalidomide maintenance therapy compared with bortezomib maintenance in MM patients post-AHCT. This study included 156 patients who received post-AHCT lenalidomide or bortezomib maintenance therapy for MM. The primary outcome was PFS. Ninety-two patients received lenalidomide maintenance and 64 received bortezomib maintenance post-AHCT. By multivariable analysis, maintenance therapy choice and cytogenetics risk did not impact PFS or OS. Staging by International Staging System and pre-maintenance disease response were the greatest predictors for PFS. Treatment-related toxicities were as anticipated with 5.4% of patients receiving maintenance lenalidomide experiencing secondary primary malignancies (SPMs) compared with 3% for bortezomib. These findings suggest there were no differences in PFS or OS between lenalidomide and bortezomib maintenance therapy options for post-transplantation MM patients. These data should be validated in a larger, prospective cohort to determine if maintenance choice should be guided by side effect profile and patient anticipated tolerance rather than by disease biology alone.

Outcomes from Autologous Hematopoietic Cell Transplantation versus Chemotherapy Alone for the Management of Light Chain Amyloidosis.

Light chain amyloidosis (AL) results in tissue deposition of misfolded proteins, causing organ dysfunction. In an era of modern therapies, such as bortezomib, reassessment of the benefit of autologous hematopoietic cell transplantation (AHCT) should be considered. In this study, we compared outcomes between patients with AL receiving chemotherapy alone (CT) and those undergoing AHCT. Seventy-four patients with AL were analyzed retrospectively. Two cohorts of patients were studied, those receiving CT (n = 31) and those undergoing AHCT (n = 43). Of the 43 patients in the AHCT cohort, 29 received induction chemotherapy before AHCT, whereas 14 proceeded straight to AHCT without induction therapy. Compared with the CT cohort, patients in the AHCT cohort were younger and had higher ejection fractions, lower brain natriuretic peptide levels, and more severe proteinuria. The majority (87%) of patients in the CT cohort received bortezomib-based treatment. Transplantation-related mortality (TRM) was 7%. Patients receiving AHCT were more likely to achieve complete or very good partial response (P = .048). The median progression-free survival (PFS) and overall survival (OS) were superior in the AHCT cohort (not reached versus 9 months; P < .01 and 74 months versus 8 months; P = .03, respectively). Multivariable analysis demonstrated that improved PFS (hazard ratio, 3.86; 95% confidence interval [CI] 1.3 to 11.5; P = .02) and OS (hazard ratio, 5.6; 95% CI, 1.9 to 16; P < .001) were associated with use of AHCT compared with CT. Patients in the AHCT cohort had deeper and longer durations of response, with superior PFS and OS, compared with those in the CT cohort. Despite the limitations of this study, AHCT should be considered for eligible patients with AL at experienced transplantation centers that can offer this therapy with a low risk of TRM.