Purpose Chronic lymphocytic leukemia (CLL) cells depend on microenvironmental interactions for proliferation and survival that are at least partially mediated through B cell receptor (BCR) signaling. Ibrutinib, a Bruton’s tyrosine kinase inhibitor, disrupts BCR signaling and leads to the egress of tumor cells from the microenvironment. While the on-target effects on CLL cells are well defined, the impact on the microenvironment is less well studied. We therefore sought to characterize the in vivo effects of ibrutinib on the tumor microenvironment. Experimental Design Patients received single agent ibrutinib on an investigator-initiated phase 2 trial. Serial blood and tissue samples were collected pre-treatment and during treatment. Changes in cytokine levels, cellular subsets and microenvironmental interactions were assessed. Results Serum levels of key chemokines and inflammatory cytokines decreased significantly in patients on ibrutinib. Further, ibrutinib treatment decreased circulating tumor cells and overall T cell numbers. Most notably, a reduced frequency of the Th17 subset of CD4+ T cells was observed concurrent with reduced activation markers and expression of PD-1 on T cells. Consistent with direct inhibition of T cells, ibrutinib inhibited Th17 differentiation of murine CD4+ T cells in vitro. Lastly, in the bone marrow microenvironment, we found that ibrutinib disaggregated the interactions of macrophages and CLL cells, inhibited secretion of CXCL13 and decreased the chemoattraction of CLL cells. Conclusions In conjunction with inhibition of BCR signaling, these changes in the tumor microenvironment likely contribute to the anti-tumor activity of ibrutinib and may impact the efficacy of immunotherapeutic strategies in patients with CLL.

Purpose Ibrutinib leads to a transient lymphocytosis in patients with chronic lymphocytic leukemia (CLL) that develops within hours of starting drug and is due to the efflux of cells from lymphoid tissues into the blood. We therefore sought to investigate the in vivo effect of ibrutinib on migration and adhesion of CLL cells. Experimental Design Patients received single agent ibrutinib (420mg daily) on an investigator-initiated phase 2 trial. Serial blood samples were collected pre-treatment and during treatment for ex vivo functional assays. Results Adhesion of CLL cells to fibronectin was rapidly (within hours) and almost completely inhibited (median reduction 98% on day 28, P<0.001), while the effect on migration to chemokines was more moderate (median reduction 64%, P=0.008) and less uniform. Although cell surface expression of key adhesion molecules such as CD49d, CD29 and CD44 were modestly reduced, this was only apparent after weeks of treatment. Stimulation of CLL cells from patients on ibrutinib with PMA, which activates PKC independent of BTK, restored the ability of the cells to adhere to fibronectin in a VLA-4 dependent manner. Lastly, the addition of ibrutinib to CLL cells adhered to fibronectin in vitro caused the detachment of 17% of the cells, on average; consistent with in vivo observations of an increasing lymphocytosis within 4 hours of starting ibrutinib. Conclusions Inhibition of BTK and VLA-4 dependent adhesion of CLL cells to stroma and stromal components provides a mechanistic explanation for the treatment-induced lymphocytosis and may reduce CD49d-dependent pro-survival signals in the tissue microenvironment.

The clinical efficacy displayed by ibrutinib in chronic lymphocytic leukemia (CLL) has been challenged by the frequent emergence of resistant clones. The ibrutinib target, Bruton's tyrosine kinase (BTK), is essential for B cell receptor signaling, and most resistant cases carry mutations in BTK or PLCG2, a downstream effector target of BTK. Recent findings show that MI-2, a small molecule inhibitor of the para-caspase MALT1, is effective in preclinical models of another type of BCR pathway-dependent lymphoma. We therefore studied the activity of MI-2 against CLL and ibrutinib-resistant CLL. Treatment of CLL cells in vitro with MI-2 inhibited MALT1 proteolytic activity, reduced BCR and NF-κB signaling, inhibited nuclear translocation of RelB and p50, and decreased Bcl-xL levels. MI-2 selectively induced dose and time-dependent apoptosis in CLL cells, sparing normal B lymphocytes. Furthermore, MI-2 abrogated survival signals provided by stromal cells and BCR cross-linking and was effective against CLL cells harboring features associated with poor outcomes, including 17p deletion and unmutated IGHV. Notably, MI-2 was effective against CLL cells collected from patients harboring mutations conferring resistance to ibrutinib. Overall, our findings provide a preclinical rationale for the clinical development of MALT1 inhibitors in CLL, in particular for ibrutinib-resistant forms of this disease.

Multi-gene panel testing has expanded the genetic information available to cancer patients. The objective was to assess provider behaviors and attitudes and patient knowledge and attitudes towards genetic counseling and testing. An online survey was distributed to Society of Gynecologic Oncology members and a written questionnaire was administered to patients diagnosed with epithelial ovarian cancer at a tertiary care referral center. Most of the 233 (18% response rate) provider respondents were gynecologic oncologists. Access to a genetic counselor was reported by 87% of providers and 55% deferred all testing to genetic counselors. Of 53 ovarian cancer patient respondents, two-thirds had previously seen a genetic counselor or undergone testing. Patients' attitudes about genetic counseling and/or testing were favorable with respect to themselves (70-81%) and their family members (94%). Less than 25% of patients indicated worrying about health care discrimination, lack of privacy, or high cost. Seventy-seven percent of patients demonstrated a desire to obtain genetic information even if the results were not currently actionable, and 20% of providers stated they test for only those genes with guideline-supported actionable results. Provider practice differences were identified in screening and prevention strategies for patients with deleterious non-BRCA mutations and variants of uncertain significance. The variation in clinical interpretation of results associated with poorly defined cancer risks signals a need for more comprehensive training and guidelines to ensure access to evidence-based care.

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Purpose To identify patient and hospital characteristics associated with extended surgical cytoreduction in the treatment of ovarian cancer. Methods A retrospective analysis using the National Inpatient Sample (NIS) database identified women hospitalized for surgery to remove an ovarian malignancy between 2013 and 2017. Extended cytoreduction (ECR) was defined as surgery involving the bowel, liver, diaphragm, bladder, stomach, or spleen. Chi-square and logistic regression were used to analyze patient and hospital demographics related to ECR, and trends were assessed using the Cochran-Armitage test. Results Of the estimated 79,400 patients undergoing ovarian cancer surgery, 22% received ECR. Decreased adjusted odds of ECR were found in patients with lower Elixhauser Comorbidity Index (ECI) scores (OR 0.61, p<0.001 for ECI 2, versus ECI≥3) or residence outside the top income quartile (OR 0.71, p<0.001 for Q1, versus Q4), and increased odds were seen at hospitals with high ovarian cancer surgical volume (OR 1.25, p<0.001, versus low volume). From 2013 to 2017, there was a decrease in the proportion of cases with extended procedures (19% to 15%, p<0.001). There were significant decreases in the proportion of cases with small bowel, colon, and rectosigmoid resections (p<0.001). Patients who underwent ECR were more likely treated at a high surgical volume hospital (37% vs 31%, p<0.001) over the study period. For their hospital admission, patients who underwent ECR had increased mortality (1.6% vs. 0.5%, p<0.001), length of stay (9.6 days vs. 5.2 days, p<0.001), and mean cost ($32,132 vs. $17,363, p<0.001). Conclusions Likelihood of ECR was associated with increased medical comorbidity complexity, higher income, and undergoing the procedure at high surgical volume hospitals. The proportion of ovarian cancer cases with ECR has decreased from 2013–17, with more cases performed at high surgical volume hospitals.

Background and Objectives: Postoperative readmissions are often used to assess quality of surgical care. This study compared 30-day vs 31-to 90-day readmission following surgery for ovarian, fallopian tube, or primary peritoneal cancer. Methods: This retrospective study of the 2010-2015 Nationwide Readmissions Database characterized 90-day readmissions following cytoreductive surgery for these cancers. Each patient's first postoperative hospitalization was included. Univariate analysis compared patient demographics and reasons for readmission. Multivariable regression identified independent predictors of readmission. Results: Of an estimated 76 652 patients, 10 264 (13.4%) were readmitted within 30 days, and 6942 (9.1%) between 31 and 90 days. The 30-day readmissions were more frequently associated with postoperative infection, while 31-to 90-day readmissions were more frequently associated with renal or hematologic diagnoses.