Plain Language Summary of the iNNOVATE study: ibrutinib plus rituximab is well-tolerated and effective in people with Waldenström's macroglobulinemia.

WHAT IS THIS SUMMARY ABOUT?: This article provides a short summary of 5-year results from the iNNOVATE trial. The original paper was published in the Journal of Clinical Oncology in October 2021. People with Waldenström's macroglobulinemia (WM) were randomly divided into two groups of 75 people each. One group received a combination treatment composed of two drugs, ibrutinib plus rituximab, and the other group took placebo ("sugar pill") plus rituximab. Ibrutinib (also known by the brand name Imbruvica®) is a drug that reduces cancer cells' ability to multiply and survive. Ibrutinib is an FDA-approved drug for the treatment of WM. Rituximab is a drug that helps the immune system find and kill cancer cells. Participants in the trial were treated and their health monitored for up to 5 years (63 months). WHAT WERE THE RESULTS?: During the 5 years of monitoring, more people who took ibrutinib plus rituximab experienced an improvement in their disease and lived longer without their disease getting worse compared to those who took placebo plus rituximab. Side effects from ibrutinib and rituximab were manageable and generally decreased over time. Participants in both study groups reported improvements in quality of life, but those who took ibrutinib plus rituximab reported significantly greater improvement in their quality of life (as measured by FACT-An score) compared to those who took placebo plus rituximab. WHAT DO THE RESULTS MEAN?: These results show that ibrutinib plus rituximab is better than rituximab alone in people with WM and that ibrutinib plus rituximab is safe and effective in the long term. This information confirms the role of ibrutinib plus rituximab as a standard of care for WM. Clinical Trial Registration: NCT02165397 (ClinicalTrials.gov).

Characterization of low-grade arthralgia, myalgia, and musculoskeletal pain with ibrutinib therapy: pooled analysis of clinical trials in patients with chronic lymphocytic leukemia and mantle cell lymphoma.

Joint and muscle pain, including arthralgia, myalgia, and musculoskeletal pain, are among the common adverse events (AEs) reported for ibrutinib, a once-daily Bruton's tyrosine kinase inhibitor approved for the treatment of various B-cell malignancies, including chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). This pooled analysis from nine clinical trials of ibrutinib in CLL and MCL (N = 1178) evaluated patterns of these AEs. Any grade arthralgia, myalgia, and musculoskeletal pain occurred in 18%, 10%, and 6% of patients, respectively. AEs were primarily low-grade (grade 1/2: 97‒99%) and occurred during the first year of treatment; most resolved (67%-80%) at first occurrence. Few (<5%) patients required ibrutinib dose modification; no patients discontinued ibrutinib due to these AEs. Among patients evaluated for concomitant medication use, all those receiving concomitant medications after the first AE occurrence experienced AE resolution. These data suggest that these AEs were not treatment-limiting during ibrutinib therapy.

Ibrutinib Plus Rituximab Versus Placebo Plus Rituximab for Waldenström's Macroglobulinemia: Final Analysis From the Randomized Phase III iNNOVATE Study.

PURPOSE: The double-blind, randomized, placebo-controlled phase III iNNOVATE study showed sustained efficacy of ibrutinib-rituximab in Waldenström's macroglobulinemia (WM). Here, we present the final analysis from iNNOVATE. METHODS: Patients had confirmed symptomatic WM, either previously untreated or previously treated; patients with prior rituximab had at least a minor response to their last rituximab-based regimen. Patients were randomly assigned to once-daily ibrutinib 420 mg plus rituximab or placebo plus rituximab (n = 75 per arm). The primary end point was progression-free survival (PFS). Secondary end points included response rate, time to next treatment, hemoglobin improvement, overall survival, and safety. RESULTS: With a median follow-up of 50 (range, 0.5-63) months, median (95% CI) PFS was not reached (57.7 months to not evaluable) with ibrutinib-rituximab versus 20.3 months (13.0 to 27.6) with placebo-rituximab (hazard ratio, 0.250; P < .0001). PFS benefit was regardless of prior treatment status, MYD88 and CXCR4 mutation status, or key patient characteristics. Higher response rates (partial response or better) were observed with ibrutinib-rituximab (76% v 31% with placebo-rituximab; P < .0001) and were sustained over time. Median time to next treatment was not reached with ibrutinib-rituximab versus 18 months with placebo-rituximab. More patients receiving ibrutinib-rituximab versus placebo-rituximab had sustained hemoglobin improvement (77% v 43%; P < .0001). Median overall survival was not reached in either arm. Ibrutinib-rituximab maintained a manageable safety profile; the prevalence of grade ≥ 3 adverse events of clinical interest generally decreased over time. CONCLUSION: In the final analysis of iNNOVATE with a median follow-up of 50 months, ibrutinib-rituximab showed ongoing superiority across clinical outcomes in patients with WM regardless of MYD88 or CXCR4 mutation status, prior treatment, and key patient characteristics.

Single-Agent Ibrutinib for Rituximab-Refractory Waldenström Macroglobulinemia: Final Analysis of the Substudy of the Phase III InnovateTM Trial.

PURPOSE: The first report from the open-label substudy of the phase III iNNOVATE study (PCYC-1127; NCT02165397) demonstrated that single-agent ibrutinib was efficacious and well tolerated in patients with heavily pretreated, rituximab-refractory Waldenström macroglobulinemia. Results from the final analysis are now reported. PATIENTS AND METHODS: Ibrutinib 420 mg was administered once daily to patients (N = 31) who failed to achieve at least a minor response (MR) or who relapsed <12 months after their last rituximab-containing therapy. Endpoints included progression-free survival (PFS) and overall response rate (ORR; MR or better) per independent review committee, hemoglobin improvement, overall survival (OS), and safety; serum IgM was also assessed. RESULTS: After a median follow-up of 58 months (range: 9-61), median PFS was 39 months [95% confidence interval (CI): 25-not evaluable]; 60-month PFS rate was 40%. In MYD88L265P/CXCR4WHIM and MYD88L265P/CXCR4WT subtypes, median PFS was 18 months and not reached, respectively. In all patients, ORR was 87%; responses deepened over time with major response (≥ partial response) rates increasing from 61% at 6 months to 77% at 60 months. Median OS was not reached. Seventeen of 21 patients (81%) with baseline hemoglobin ≤11.0 g/dL had sustained hemoglobin improvement. Improvements in serum IgM levels were sustained, reaching a maximum median change of -37 g/L at 54 months. Ibrutinib maintained a manageable safety profile, with no new safety signals identified. There were no events of major hemorrhage or atrial fibrillation. CONCLUSIONS: In the final analysis from iNNOVATE, single-agent ibrutinib continued to show sustained efficacy in patients with heavily pretreated, rituximab-refractory Waldenström macroglobulinemia.

Durable ibrutinib responses in relapsed/refractory marginal zone lymphoma: long-term follow-up and biomarker analysis.

Advanced marginal zone lymphoma (MZL) is an incurable B-cell malignancy dependent on B-cell receptor signaling. The phase 2 PCYC-1121 study demonstrated the safety and efficacy of single-agent ibrutinib 560 mg/d in 63 patients with relapsed/refractory MZL treated with prior rituximab (RTX) or rituximab-based chemoimmunotherapy (RTX-CIT). We report the final analysis of PCYC-1121 with median follow-up of 33.1 months (range: 1.4-44.6). Overall response rate (ORR) was 58%; median duration of response (DOR) was 27.6 months (95% confidence interval [CI]: 12.1 to not estimable [NE]); median progression-free survival (PFS) was 15.7 months (95% CI: 12.2-30.4); and median overall survival (OS) was not reached (95% CI: NE to NE). Patients with prior RTX treatment had better outcomes (ORR: 81%; median DOR: not reached [95% CI: 12.2 to NE]; median PFS: 30.4 months [95% CI: 22.1 to NE]; median OS: not reached [95% CI: 30.3 to NE]) vs those with prior RTX-CIT treatment (ORR: 51%; DOR: 12.4 months [95% CI: 2.8 to NE]; PFS: 13.8 months [95% CI: 8.3-22.5]; OS: not reached [95% CI: NE to NE]). ORRs were 63%, 47%, and 62% for extranodal, nodal, and splenic subtypes, respectively. With up to 45 months of ibrutinib treatment, the safety profile remained consistent with prior reports. The most common grade ≥3 event was anemia (16%). Exploratory biomarker analysis showed NF-κB pathway gene mutations correlated with outcomes. Final analysis of PCYC-1121 demonstrated long-term safety and efficacy of ibrutinib in patients with relapsed/refractory MZL, regardless of prior treatment or MZL subtype. This trial was registered at www.clinicaltrials.gov as #NCT01980628.

Osteoactivin, an anabolic factor that regulates osteoblast differentiation and function.

Osteoactivin (OA) is a novel glycoprotein that is highly expressed during osteoblast differentiation. Using Western blot analysis, our data show that OA protein has two isoforms, one is transmembranous and the other is secreted into the conditioned medium of primary osteoblasts cultures. Fractionation of osteoblast cell compartments showed that the mature, glycosylated OA isoform of 115 kDa is found in the membranous fraction. Both OA isoforms (secreted and transmembrane) are found in the cytoplasmic fraction of osteoblasts. Overexpression of EGFP-tagged OA in osteoblasts showed that OA protein accumulates into vesicles for transportation to the cell membrane. We examined OA protein production in primary osteoblast cultures and found that OA is maximally expressed during the third week of culture (last stage of osteoblast differentiation). Glycosylation studies showed that OA isoform of 115 kDa is highly glycosylated. We also showed that retinoic acid (RA) stimulates the mannosylation of OA protein. In contrast, tunicamycin (TM) strongly inhibited N-glycans incorporation into OA protein. The functional role of the secreted OA isoform was revealed when cultures treated with anti-OA antibody, showed decreased osteoblast differentiation compared to untreated control cultures. Gain-of-function in osteoblasts using the pBABE viral system showed that OA overexpression in osteoblast stimulated their differentiation and function. The availability of a naturally occurring mutant mouse with a truncated OA protein provided further evidence that OA is an important factor for terminal osteoblast differentiation and mineralization. Using bone marrow mesenchymal cells derived from OA mutant and wild-type mice and testing their ability to differentiate into osteoblasts showed that differentiation of OA mutant osteoblasts was significantly reduced compared to wild-type osteoblasts. Collectively, our data suggest that OA acts as a positive regulator of osteoblastogenesis.

Osteoactivin acts as downstream mediator of BMP-2 effects on osteoblast function.

Our laboratory previously showed that osteoactivin (OA) is a novel, osteoblast-related glycoprotein that plays a role in osteoblast differentiation and function. The purpose of this study was to examine the regulation of OA expression by BMP-2 and the role OA plays as a downstream mediator of BMP-2 effects in osteoblast function. Using primary osteoblast cultures, we tested different doses of BMP-2 on the regulation of OA expression during osteoblast development. To test whether Smad-1 signaling is responsible for BMP-2 regulation of OA expression, osteoblast cultures were transfected with Smad1 siRNA, treated with 50 ng/ml of BMP-2 and analyzed by Western blot. BMP-2 treatment increased OA mRNA and protein expression in a dose-dependent manner and this upregulation was blocked in Smad1 siRNA transfected cultures. We next examined whether the role of OA as a downstream mediator of BMP-2 effects on osteoblast differentiation and matrix mineralization. Osteoblast cultures were transfected with OA antisense oligonucleotides and treated with 50 ng/ml of BMP-2. Cultures transfected with OA antisense oligonucleotides and treated with BMP-2 showed a reduction of OA expression associated with a significant reduction in early and late differentiation markers induced by BMP-2. Therefore, OA acts, at least in part, as a downstream mediator of BMP-2 effects on osteoblast differentiation and matrix mineralization. Our findings suggest that BMP-2 regulates OA expression through the Smad1 signaling pathway. Our data also emphasize that OA protein acts as a downstream mediator of BMP-2 effects on osteoblast differentiation and function.