Contemporary Systemic Therapy Intensification for Prostate Cancer: A Review for General Practitioners in Oncology.

Prostate cancer accounts for a significant proportion of cancer diagnoses in Canadian men. Over the past decade, the therapeutic landscape for the management of metastatic prostate cancer has undergone rapid changes. Novel strategies use hormonal agents, chemotherapy, homologous recombination repair inhibitors, and radioligand therapy or combination strategies in addition to androgen deprivation therapy. In this review, we summarize the available data addressing key therapeutic areas along the disease continuum and focus on practical aspects for general practitioners in oncology managing patients with metastatic prostate cancer.

Cognition and depression effects of androgen receptor axis-targeted drugs in men with prostate cancer: A systematic review.

CONTEXT: Novel androgen receptor axis-targeting drugs (ARATs) have been shown to improve outcomes in men with prostate cancer. Central nervous system androgen blockade may be harmful for older adults who may be at increased risk of adverse cognitive and psychologic effects. OBJECTIVE: To systematically evaluate the effect of ARATs on cognition and depression in men with metastatic prostate cancer. EVIDENCE ACQUISITION: We searched PubMed and EMBASE for articles published in English between September 2012 and September 2019 reporting cognition and depression outcomes in men receiving ARATs for metastatic prostate cancer using validated psychometric tools. The level of evidence and risk of bias were assessed using the GRADE approach for randomized clinical trials and observational studies. RESULTS: 15 reports studying 8954 men with metastatic castration-sensitive and -resistant, or non-metastatic castration-resistant prostate cancer were identified. Data were available for abiraterone, enzalutamide and apalutamide but not darolutamide. The mean (and 95% confidence interval) and median (and min-max) of the absolute scores and changes from baseline were included, when available. There was heterogeneity in the psychometric tools used which obviated statistical pooling of results. Very limited data assessing cognition suggested that abiraterone was associated with improved cognitive functioning or perhaps less cognitive harm versus enzalutamide. Fourteen reports assessed emotional wellbeing. ARATs reduced depressive symptoms when compared to prednisone alone or placebo but not compared to bicalutamide. Abiraterone may improve short-term emotional functioning relative to enzalutamide. The quality of evidence was low when examining ARAT effect on cognitive function and moderate when examining ARAT effect on depression. CONCLUSIONS: Depression was assessed more frequently than cognition in men receiving ARATs. Self-reported depression measures favored abiraterone over enzalutamide and both abiraterone and enzalutamide over placebo. Data evaluating apalutamide and darolutamide are lacking. Further studies of ARATs using validated clinician-based psycho-cognition tools along with self-reported measures in men with metastatic prostate cancer are needed.

Predictors of Survival Benefit From Immune Checkpoint Inhibitors in Patients With Advanced Non-small-cell Lung Cancer: A Systematic Review and Meta-analysis.

Randomized trials showed inconsistent survival benefit with immune checkpoint inhibitors (ICIs) in patients with advanced non-small-cell lung cancer with low programmed death-ligand 1 (PD-L1) tumors (< 1%) and in elderly patients (> 65 years old) and never-smokers. We conducted a systematic review and meta-analysis to assess the efficacy of single agent ICIs in these pre-defined subgroups. The electronic databases PubMed and EMBASE were searched for relevant randomized trials. Pooled hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) were meta-analyzed using the generic inverse variance method. Nine studies were included. Compared with chemotherapy, the use of single agent ICIs in the second-line setting reduced the risk of death independent of PD-L1 expression (HR, 0.79; 95% confidence interval [CI], 0.66-0.96 and HR, 0.75; 95% CI, 0.61-0.85 for patients with PD-L1-negative and -positive tumors, respectively). Yet, a PFS benefit was only seen in patients with PD-L1-positive tumors. Similarly, an OS benefit was seen in patients independent of age (HR, 0.79; 95% CI, 0.69-0.89 and HR, 0.76; 95% CI, 0.66-0.88 for elderly and non-elderly patients, respectively). Conversely, an OS benefit was only seen in ever-smokers (HR, 0.78; 95% CI, 0.68-0.89) and a detrimental effect on PFS in never-smokers (HR, 1.68; 95% CI, 1.07-2.63). Patients with advanced non-small-cell lung cancer derive a survival benefit from ICIs independent of tumor PD-L1 expression and age, particularly in the second line, whereas never-smokers do not. Caution should be exercised when offering single-agent ICIs to elderly patients in the first line, and other treatment options should be considered in never-smokers.

Early experience with chemotherapy intensification for poor-prognosis metastatic germ cell cancer and unfavorable tumor marker decline.

INTRODUCTION: Intensified chemotherapy improved outcomes for men with poor-prognosis metastatic germ cell cancer (GCC) and unfavorable tumor marker decline after one cycle of bleomycin, etoposide, and cisplatin (BEP) chemotherapy in the GETUG-13 trial. Herein, we report our experience to date using a similar approach. METHODS: Patients were identified from our electronic GCC database. Men with poor-prognosis GCC and unfavorable tumor marker decline were offered intensified chemotherapy consisting of T-BEP (three cycles) plus paclitaxel, ifosfamide, and cisplatin (TIP) (one cycle), along with prophylactic granulocyte-colony stimulating factor (G-CSF) and resection of residual masses. Cisplatin, etoposide, and ifosfamide (PEI) replaced the last cycle of T-BEP for bleomycin pulmonary concerns. Serious toxicities, progression-free survival, and overall survival were evaluated retrospectively. RESULTS: Ten patients with poor-prognosis GCC were identified from May 2012 to April 2016. Eight patients had unfavorable tumor marker decline. Six were offered and received intensified chemotherapy (two T-BEPx3 + TIP and four T-BEPx2 + PEI + TIP). Serious toxicities included neutropenic sepsis, deep venous thrombosis, and C. difficile colitis, but there were no toxic deaths. One patient died of synchronous metastatic adenocarcinoma ex teratoma. The remaining five patients achieved marker-negative partial response, two had residual mature teratoma excised, and four have no evidence of disease after surgery. All are alive at a median of 63.5 months (range 46.3-65.6); one patient has grade 2 peripheral sensory neuropathy, and one patient has grade 2 cognitive disturbance. Of four patients treated with standard BEP, two have died of disease and two are alive at 51.4 and 53.6 months. CONCLUSIONS: Our experience with intensified chemotherapy for men with poor-prognosis GCC and unfavorable tumor marker decline confirms that it is feasible, reasonably safe, and appears to provide results similar to those reported in GETUG-13.

Emerging cell cycle inhibitors for treating metastatic castration-resistant prostate cancer.

INTRODUCTION: Disease progression despite androgen suppression defines lethal castration-resistant prostate cancer (CRPC). Most of these cancers remain androgen receptor (AR)-signaling dependent. Therapy for metastatic CRPC includes abiraterone acetate, enzalutamide, docetaxel, cabazitaxel, sipuleucel-T, and radium-223. However, survival remains modest for men with progressive disease despite AR-targeted therapy and docetaxel, and therefore novel treatments are needed. Areas covered: Recent evidence of genomic heterogeneity and sensitivity to PARP inhibitors supports investigation of targeted agents in CRPC. Cell cycle inhibitors are therefore logical molecules to investigate. Review of the current literature identified cell cycle inhibitors under study in early phase clinical trials targeting the G1 (palbociclib, ribociclib, AZD-5363, ipatasertib), S (M-6620, prexasertib), G2 (adavosertib), and M (alisertib) phases of the cell cycle. Expert opinion: Strategies combining cell cycle inhibitors with active agents in CRPC are most likely to have clinical impact with CDK4/6 and Wee1 inhibitors appearing most promising. Identification of predictive biomarkers may be essential and currently trials are testing circulating cell-free DNA as an approach. Incremental toxicities such as neutropenia are important in this population. Results from most current clinical trials of cell cycle inhibitors in CRPC are still pending but it is anticipated they will provide important insights into the heterogeneous biology of CRPC.

Binding and inhibition of the ternary complex factor Elk-4/Sap1 by the adapter protein Dok-4.

The adapter protein Dok-4 (downstream of kinase-4) has been reported as both an activator and inhibitor of Erk and Elk-1, but lack of knowledge about the identity of its partner molecules has precluded any mechanistic insight into these seemingly conflicting properties. We report that Dok-4 interacts with the transactivation domain of Elk-4 through an atypical phosphotyrosine-binding domain-mediated interaction. Dok-4 possesses a nuclear export signal and can relocalize Elk-4 from nucleus to cytosol, whereas Elk-4 possesses two nuclear localization signals that restrict interaction with Dok-4. The Elk-4 protein, unlike Elk-1, is highly unstable in the presence of Dok-4, through both an interaction-dependent mechanism and a pleckstrin homology domain-dependent but interaction-independent mechanism. This is reversed by proteasome inhibition, depletion of endogenous Dok-4 or lysine-to-arginine mutation of putative Elk-4 ubiquitination sites. Finally, Elk-4 transactivation is potently inhibited by Dok-4 overexpression but enhanced by Dok-4 knockdown in MDCK renal tubular cells, which correlates with increased basal and EGF-induced expression of Egr-1, Fos and cylcinD1 mRNA, and cell proliferation despite reduced Erk activation. Thus, Dok-4 can target Elk-4 activity through multiple mechanisms, including binding of the transactivation domain, nuclear exclusion and protein destabilization, without a requirement for inhibition of Erk.

Expression of integrin α3ß1 and cyclooxygenase-2 (COX2) are positively correlated in human breast cancer.

BACKGROUND: Expression of integrin α3ß1 is associated with tumor progression, metastasis, and poor prognosis in several cancers, including breast cancer. Moreover, preclinical studies have revealed important pro-tumorigenic and pro-metastatic functions for this integrin, including tumor growth, survival, invasion, and paracrine induction of angiogenesis. Our previously published work in a preclinical breast cancer model showed that integrin α3ß1 promotes expression of cyclooxygenase-2 (COX2/PTGS2), a known driver of breast cancer progression. However, the clinical significance of this regulation was unknown. The objective of the current study was to assess the clinical relevance of the relationship between integrin α3ß1 and COX2 by testing for their correlated expression among various forms of human breast cancer. METHODS: Immunohistochemistry was performed to assess co-expression of α3 and COX2 in specimens of human invasive ductal carcinoma (IDC), either on a commercial tissue microarray (n = 59 samples) or obtained from Albany Medical Center archives (n = 68 samples). Immunostaining intensity for the integrin α3 subunit or COX2 was scored, and Spearman's rank correlation coefficient analysis was performed to assess their co-expression across and within different tumor subtypes or clinicopathologic criteria. RESULTS: Although expression of integrin α3 or COX2 varied among clinical IDC samples, a statistically significant, positive correlation was detected between α3 and COX2 in both tissue microarrays (r(s) = 0.49, p < 0.001, n = 59) and archived samples (r(s) = 0.59, p < 0.0001, n = 68). In both sample sets, this correlation was independent of hormone receptor status, histological grade, or disease stage. CONCLUSIONS: COX2 and α3 are correlated in IDC independently of hormone receptor status or other clinicopathologic features, supporting the hypothesis that integrin α3ß1 is a determinant of COX2 expression in human breast cancer. These results support the clinical relevance of α3ß1-dependent COX2 gene expression that we reported previously in breast cancer cells. The findings also suggest that COX2-positive breast carcinomas of various subtypes might be vulnerable to therapeutic strategies that target α3ß1, and that α3 expression might serve as an independent prognostic biomarker.