The greatest risk factor for developing carcinoma of the prostate is advanced age. Potential molecular and physiologic contributors to the frequency of cancer occurrence in older individuals include the accumulation of somatic mutations through defects in genome maintenance, epigenetic gene silencing, oxidative stress, loss of immune surveillance, telomere dysfunction, chronic inflammation, and alterations in tissue microenvironment. In this context, the process of prostate carcinogenesis can be influenced through interactions between intrinsic cellular alterations and the extrinsic microenvironment and macroenvironment, both of which change substantially as a consequence of aging. In this study, we sought to characterize the molecular alterations that occur during the process of prostate fibroblast senescence to identify factors in the aged tissue microenvironment capable of promoting the proliferation and potentially the neoplastic progression of prostate epithelium. We evaluated three mechanisms leading to cell senescence: oxidative stress, DNA damage, and replicative exhaustion. We identified a consistent program of gene expression that includes a subset of paracrine factors capable of influencing adjacent prostate epithelial growth. Both direct coculture and conditioned medium from senescent prostate fibroblasts stimulated epithelial cell proliferation, 3-fold and 2-fold, respectively. The paracrine-acting proteins fibroblast growth factor 7, hepatocyte growth factor, and amphiregulin (AREG) were elevated in the extracellular environment of senescent prostate fibroblasts. Exogenous AREG alone stimulated prostate epithelial cell growth, and neutralizing antibodies and small interfering RNA targeting AREG attenuated, but did not completely abrogate the growthpromoting effects of senescent fibroblast conditioned medium. These results support the concept that aging-related changes in the prostate microenvironment may contribute to the progression of prostate neoplasia. (Cancer Res 2006; 66(2): 794-802)

Ibrutinib, a once-daily oral inhibitor of Bruton's tyrosine kinase, is approved in the United States and Europe for treatment of patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). The phase 3 RESONATE study showed improved efficacy of single-agent ibrutinib over ofatumumab in patients with relapsed/refractory CLL/SLL, including those with high-risk features. Here we report the final analysis from RESONATE with median follow-up on study of 65.3 months (range, 0.3-71.6) in the ibrutinib arm. Median progression-free survival (PFS) remained significantly longer for Trial Registration: clinicaltrials.gov identifier: NCT01578707.

RESONATE-2 is a phase 3 study of first-line ibrutinib versus chlorambucil in chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Patients aged ≥65 years (n = 269) were randomized 1:1 to once-daily ibrutinib 420 mg continuously or chlorambucil 0.5-0.8 mg/kg for ≤12 cycles. With a median (range) follow-up of 60 months (0.1-66), progression-free survival (PFS) and overall survival (OS) benefits for ibrutinib versus chlorambucil were sustained (PFS estimates at 5 years: 70% vs 12%; HR [95% CI]: 0.146 [0.098-0.218]; OS estimates at 5 years: 83% vs 68%; HR [95% CI]: 0.450 [0.266-0.761]). Ibrutinib benefit was also consistent in patients with high prognostic risk (TP53 mutation, 11q deletion, and/or unmutated IGHV) (PFS: HR [95%

CTI BioPharma Corp.

PURPOSE CAPTIVATE ( NCT02910583 ), a randomized phase II study, evaluates minimal residual disease (MRD)-guided treatment discontinuation following completion of first-line ibrutinib plus venetoclax treatment in patients with chronic lymphocytic leukemia (CLL). METHODS Previously untreated CLL patients age < 70 years received three cycles of ibrutinib and then 12 cycles of combined ibrutinib plus venetoclax. Patients in the MRD cohort who met the stringent random assignment criteria for confirmed undetectable MRD (Confirmed uMRD) were randomly assigned 1:1 to double-blind placebo or ibrutinib; patients without Confirmed uMRD (uMRD Not Confirmed) were randomly assigned 1:1 to open-label ibrutinib or ibrutinib plus venetoclax. Primary end point was 1-year disease-free survival (DFS) rate with placebo versus ibrutinib in the Confirmed uMRD population. Secondary end points included response rates, uMRD, and safety. RESULTS One hundred sixty-four patients initiated three cycles of ibrutinib lead-in. After 12 cycles of ibrutinib plus venetoclax, best uMRD response rates were 75% (peripheral blood) and 68% (bone marrow). Patients with Confirmed uMRD were randomly assigned to receive placebo (n = 43) or ibrutinib (n = 43); patients with uMRD Not Confirmed were randomly assigned to ibrutinib (n = 31) or ibrutinib plus venetoclax (n = 32). Median follow-up was 31.3 months. One-year DFS rate was not significantly different between placebo (95%) and ibrutinib (100%; arm difference: 4.7% [95% CI, –1.6 to 10.9]; P = .15) in the Confirmed uMRD population. After ibrutinib lead-in tumor debulking, 36 of 40 patients (90%) with high tumor lysis syndrome risk at baseline shifted to medium or low tumor lysis syndrome risk categories. Adverse events were most frequent during the first 6 months of ibrutinib plus venetoclax and generally decreased over time. CONCLUSION The 1-year DFS rate of 95% in placebo-randomly assigned patients with Confirmed uMRD suggests the potential for fixed-duration treatment with this all-oral, once-daily, chemotherapy-free regimen in first-line CLL.

The safety and efficacy of ibrutinib, a once-daily Bruton's tyrosine kinase (BTK) inhibitor, in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) was demonstrated in this phase Ib/II study. Extended follow-up up to 8 years is described, representing the longest follow-up for single-agent ibrutinib, or any BTK inhibitor, to date.Patients and Methods: Phase Ib/II PCYC-1102 (NCT01105247) and extension study PCYC-1103 (NCT01109069) included patients receiving single-agent ibrutinib in first-line or relapsed/refractory CLL/SLL.Results: Overall response rate was 89%, with similar rates in first-line (87%; complete response, 35%) and relapsed/refractory settings (89%; 10%). Estimated 7-year progression-free survival (PFS) rates were 83% in first-line and 34% in relapsed/refractory settings. Forty-one patients had CLL progression (n ¼ 11 with Richter's transformation). Median PFS was not reached with first-line ibrutinib. In relapsed/refractory CLL/SLL, median PFS was 52 months overall, 26 months in patients with chromosome 17p deletion, 51 months with 11q deletion, not reached with trisomy 12 or 13q deletion, and 88 months in patients without these cytogenetic abnormalities. Estimated 7-year overall survival rates were 84% in first-line and 55% in relapsed/refractory settings. Grade ≥3 adverse events (AE) in >15% of patients were hypertension (28%), pneumonia (24%), and neutropenia (18%). These grade ≥3 AEs generally declined over time, except hypertension. AEs leading to discontinuation in ≥2 patients were observed only in the relapsed/refractory setting (sepsis, diarrhea, subdural hematoma, and Richter's transformation).Conclusions: With up to 8 years of follow-up, sustained responses and long-term tolerability of single-agent ibrutinib were observed with treatment of first-line or relapsed/refractory CLL/SLL, including high-risk CLL/SLL.

CAPTIVATE (NCT02910583) is an international phase 2 study in patients aged ≤70 years with previously untreated chronic lymphocytic leukemia (CLL). Results from the cohort investigating fixed-duration treatment with ibrutinib plus venetoclax are reported. Patients received 3 cycles of ibrutinib lead-in then 12 cycles of ibrutinib plus venetoclax (oral ibrutinib [420 mg/day]; oral venetoclax [5-week ramp-up to 400 mg/day]). Primary endpoint was complete response (CR) rate. Hypothesis testing was performed for patients without del(17p) with prespecified analyses in all treated patients. Secondary endpoints included undetectable minimal residual disease (uMRD) rates, progression-free survival (PFS), overall survival (OS), and safety. 159 patients were enrolled and treated, including 136 patients without del(17p). Median time on study was 27.9 months and 92% of patients completed all planned treatment. Primary endpoint was met, with CR rate of 56% (95% CI, 48-64) in patients without del(17p), significantly higher than prespecified 37% minimum rate (P&lt;.0001). In the all-treated population, CR rate was 55% (95% CI, 48-63); best uMRD rates were 77% (peripheral blood) and 60% (bone marrow); 24-month PFS and OS rates were 95% and 98%, respectively. At baseline, 21% of patients were in the high tumor burden category for tumor lysis syndrome risk; after ibrutinib lead-in, only 1% remained in this category. Most common grade ≥3 adverse events were neutropenia (33%) and hypertension (6%). First-line ibrutinib plus venetoclax represents the first all-oral, once-daily, chemotherapy-free, fixed-duration regimen for patients with CLL. Fixed-duration ibrutinib plus venetoclax achieved deep, durable responses and promising PFS, including in patients with high-risk features.

Ibrutinib, a first-in-class once-daily oral Bruton tyrosine kinase inhibitor indicated for chronic lymphocytic leukemia (CLL), is continued until progressive disease or unacceptable toxicity. We conducted an integrated safety analysis of single-agent ibrutinib from randomized phase 3 studies PCYC-1112 (RESONATE, n = 195) and PCYC-1115/1116 (RESONATE-2, n = 135), and examined longer-term safety separately in the phase 1b/2 PCYC-1102/1103 study (n = 94, 420 mg/d). In the integrated analysis (ibrutinib treatment up to 43 months), the most common adverse events (AEs) were primarily grade 1/2; diarrhea (n = 173, 52% any-grade; n = 15, 5% grade 3) and fatigue (n = 119, 36% any-grade; n = 10, 3% grade 3). The most common grade 3/4 AEs were neutropenia (n = 60, 18%) and pneumonia (n = 38, 12%). Over time, prevalence of AEs of interest (diarrhea, fatigue, grade ≥3 infection, bleeding, and neutropenia) trended down; prevalence of hypertension increased, but incidence decreased after year 1. AEs led to dose reductions in 42 (13%) patients and permanent discontinuations in 37 (11%); dose modifications due to AEs were most common during year 1 and decreased in frequency thereafter. The most common AEs (preferred term) contributing to discontinuation included pneumonia (n = 4), anemia (n = 3), and atrial fibrillation (n = 3). With long-term follow-up on PCYC-1102/1103 (ibrutinib treatment up to 67 months), grade 3/4 AEs were generally similar to those in the integrated analysis. Overall, AEs were primarily grade 1/2 and manageable during prolonged ibrutinib treatment in patients with CLL. These trials were registered at www.clinicaltrials.gov as #NCT01578707, #NCT01722487, #NCT01724346, #NCT01105247, and #NCT01109069.