Julie N. Graff

Early evidence of anti-PD-1 activity in enzalutamide-resistant prostate cancer.

While programmed cell death 1 (PD-1) inhibitors have shown clear anti-tumor efficacy in several solid tumors, prior results in men with metastatic castration resistant prostate cancer (mCRPC) showed no evidence of activity. Here we report unexpected antitumor activity seen in mCRPC patients treated with the anti-PD-1 antibody pembrolizumab. Patients with evidence of progression on enzalutamide were treated with pembrolizumab 200 mg IV every 3 weeks for 4 doses; pembrolizumab was added to standard dose enzalutamide. Three of the first ten patients enrolled in this ongoing phase II trial experienced rapid prostate specific antigen (PSA) reductions to ≤ 0.2 ng/ml. Two of these three patients had measurable disease upon study entry; both achieved a partial response. There were three patients with significant immune-related adverse events. One had grade 2 myositis, one had grade 3 hypothyroidism, and one had grade 2 hypothyroidism. None of these patients had a response. Two of the three responders had a baseline tumor biopsy. Immunohistochemistry from those biopsies showed the presence of CD3+, CD8+, and CD163+ leukocyte infiltrates and PD-L1 expression. Genetic analysis of the two responders revealed markers of microsatellite instability in one. The surprising and robust responses seen in this study should lead to re-examination of PD-1 inhibition in prostate cancer.

C-reactive protein as an adverse prognostic marker for men with castration-resistant prostate cancer (CRPC): confirmatory results.

We previously reported that higher serum concentrations of C-reactive protein (CRP) are associated with shorter survival in men with castration-resistant prostate cancer (CRPC). To confirm this finding in an independent data set, we used 119 CRPC patients enrolled in 6 phase II clinical trials and examined the relationship of CRP, alkaline phosphatase, hemoglobin, age, ECOG PS, and prostate specific antigen (PSA) with survival. Median follow-up was 19.7 months (0.9-98.5 months), and 89% have died. After analyzing the form of the risk function using the generalized additive model method, univariate and multivariate Cox proportional hazard models were used to assess associations between baseline individual categorical and continuous variables. Quartiles of CRP were: 0-1.0, 1.1-4.9, 5.0-17.0, and 17.1-311 mg/L. In a Cox multivariate model, log(2) (CRP) (HR 1.106, P = 0.013) as well as hemoglobin and alkaline phosphatase were independently associated with survival, confirming that higher CRP is associated with shorter survival in CRPC. Since CRP is a marker of inflammation, this finding suggests that inflammation may play an important role in the natural history of advanced prostate cancer. CRP is a readily measurable biomarker that has the potential to improve prognostic models and should be validated in a prospective clinical trial.

Apalutamide Treatment and Metastasis-free Survival in Prostate Cancer

Background Apalutamide, a competitive inhibitor of the androgen receptor, is under development for the treatment of prostate cancer. We evaluated the efficacy of apalutamide in men with nonmetastatic castration‐resistant prostate cancer who were at high risk for the development of metastasis. Methods We conducted a double‐blind, placebo‐controlled, phase 3 trial involving men with nonmetastatic castration‐resistant prostate cancer and a prostate‐specific antigen doubling time of 10 months or less. Patients were randomly assigned, in a 2:1 ratio, to receive apalutamide (240 mg per day) or placebo. All the patients continued to receive androgen‐deprivation therapy. The primary end point was metastasis‐free survival, which was defined as the time from randomization to the first detection of distant metastasis on imaging or death. Results A total of 1207 men underwent randomization (806 to the apalutamide group and 401 to the placebo group). In the planned primary analysis, which was performed after 378 events had occurred, median metastasis‐free survival was 40.5 months in the apalutamide group as compared with 16.2 months in the placebo group (hazard ratio for metastasis or death, 0.28; 95% confidence interval [CI], 0.23 to 0.35; P<0.001). Time to symptomatic progression was significantly longer with apalutamide than with placebo (hazard ratio, 0.45; 95% CI, 0.32 to 0.63; P<0.001). The rate of adverse events leading to discontinuation of the trial regimen was 10.6% in the apalutamide group and 7.0% in the placebo group. The following adverse events occurred at a higher rate with apalutamide than with placebo: rash (23.8% vs. 5.5%), hypothyroidism (8.1% vs. 2.0%), and fracture (11.7% vs. 6.5%). Conclusions Among men with nonmetastatic castration‐resistant prostate cancer, metastasis‐free survival and time to symptomatic progression were significantly longer with apalutamide than with placebo. (Funded by Janssen Research and Development; SPARTAN ClinicalTrials.gov number, NCT01946204.)

Efficacy and safety of enzalutamide in patients 75 years or older with chemotherapy-naive metastatic castration-resistant prostate cancer: results from PREVAIL

BACKGROUND Prostate cancer disproportionately affects older men. Because age affects treatment decisions, it is important to understand the efficacy and tolerability of therapies for advanced prostate cancer in elderly men. This analysis describes efficacy and safety outcomes in men aged ≥75 years who received enzalutamide, an androgen receptor inhibitor, in the phase III PREVAIL trial. PATIENTS AND METHODS PREVAIL was a randomised, double-blind, multinational study of oral enzalutamide 160 mg/day (N = 872) versus placebo (N = 845) in chemotherapy-naive men with metastatic castration-resistant prostate cancer. Overall survival (OS) and radiographic progression-free survival (rPFS) were coprimary end points. Subgroup analysis of men aged ≥75 years (elderly) and men aged <75 years was pre-specified for the coprimary end points and adverse events (AEs). RESULTS Among 609 elderly patients (35%) who participated in PREVAIL, median treatment duration was 16.6 and 5.0 months in the enzalutamide and placebo arms, respectively. In the elderly subgroup, OS was greater with enzalutamide than with placebo [32.4 months (95% confidence interval (CI) 27.7-not yet reached] versus 25.1 months (95% CI 22.6-28.0); hazard ratio (HR) = 0.61 (95% CI 0.47-0.79); P = 0.0001], as was rPFS [not yet reached (95% CI 12.3-not yet reached) versus 3.7 months (95% CI 3.6-5.3); HR = 0.17 (95% CI 0.12-0.24); P < 0.0001]. Irrespective of treatment assignment, incidence of AEs was similar between the two age groups, except for an overall higher incidence of falls among elderly patients than younger patients [84/609 (13.8%) versus 62/1106 (5.6%)] and among elderly patients receiving enzalutamide than those receiving placebo [61/317 (19.2%) versus 23/292 (7.9%)]. CONCLUSIONS Elderly men benefited from treatment with enzalutamide in terms of OS and rPFS. Enzalutamide was well tolerated in the elderly subgroup and those aged <75 years. Age and enzalutamide treatment were associated with a higher incidence of falls. CLINICAL TRIAL IDENTIFIER NCT01212991, ClinicalTrials.gov.

Sustained complete response to CTLA-4 blockade in a patient with metastatic, castration-resistant prostate cancer

Graff and colleagues analyzed sera and biopsies from a prostate cancer patient, which showed amplification of the 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) gene with strong protein expression, suggesting that the augmented antibody response to HIBCH contributed to the durable immune response in prostate cancer. We present the case of a man with metastatic, castration-resistant prostate cancer, who had a complete prostate-specific antigen (PSA) response after 2½ doses of ipilimumab. His treatment course was complicated by diarrhea and autoimmune hepatitis, both of which resolved within 4 months. Sera and biopsy specimens were accessed, and sera from pretreatment and day 113 were analyzed. Augmented antibody responses were detected against 11 potential tumor antigens, with responses ranging from 5- to 20-fold in day 113 sera compared with baseline. Genes that were targets of a strong antibody response (arbitrarily set at 10-fold or greater increase) were analyzed by real-time PCR for expression in the tumor biopsy cDNA. Of the top 5 genes, only 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) could be identified in the amplified tumor biopsy cDNA. Using an antibody to HIBCH, immunohistochemical analysis documented strong expression of the protein. Together, these data suggest that an augmented antibody response to HIBCH, an antigen that was expressed by the patients prostate cancer, could have contributed to the clinical response. After 16 months of PSA stability, he discontinued his androgen-suppression therapy. With the return of his testosterone, his PSA increased slightly, likely originating from his intact prostate. He has been disease free for the past 6 years without any additional therapy. Cancer Immunol Res; 2(5); 399–403. ©2014 AACR.

Sipuleucel-T in the treatment of prostate cancer: An evidence-based review of its place in therapy

Metastatic castration-resistant prostate cancer is the lethal form of cancer of the prostate. Five new agents that prolong survival in this group have emerged in the past 5 years, and sipuleucel-T is among them. Sipuleucel-T is the only immunotherapy shown to improve survival in prostate cancer. It is currently indicated in asymptomatic or mildly symptomatic patients, as it has never shown a direct cancer effect. This paper describes the process of creating the sipuleucel-T product from the manufacturing and patient aspects. It discusses the four placebo-controlled, randomized clinical trials (RCTs) of sipuleucel-T, focusing on survival and adverse events. There are three RCTs in metastatic castration-resistant prostate cancer, all of which showed improved overall survival without meaningful decreases in symptoms, tumor volumes, or prostate-specific antigen levels. One RCT in castration-sensitive, biochemically relapsed prostate cancer attempted to find a decrease in biochemical failure, but that endpoint was not reached. Adverse events in all four of these studies centered around cytokine release. This paper also reviews a Phase II study of sipuleucel-T given neoadjuvantly that speaks to its mechanism of action. Additionally, there is a registry study of sipuleucel-T that has been used to evaluate immunological parameters of the product in men ≥80 years of age and men who had previously been treated with palliative radiation. Attempts to find early markers of response to sipuleucel-T are described. Further ongoing studies that explore the efficacy of sipuleucel-T in combination with immune checkpoint inhibitors and second-generation hormonal therapies that are summarized. Finally, the only published economic analysis of sipuleucel-T is discussed.

Complete Biochemical (Prostate-specific Antigen) Response to Sipuleucel-T With Enzalutamide in Castration-resistant Prostate Cancer: A Case Report With Implications for Future Research

OBJECTIVE To describe the case of a patient with castration-resistant, metastatic prostate cancer who achieved a complete and durable biochemical response after treatment with sipuleucel-T while continuing with enzalutamide and to explore the immunologic basis for such a response. MATERIALS AND METHODS We obtained serial prostate-specific antigen (PSA) measurements and bone scans to assess the patients response to enzalutamide followed by the addition of sipuleucel-T. Using preclinical and clinical data, we describe his response through known immunobiologic mechanisms. RESULTS This patients PSA level became undetectable during treatment with enzalutamide and began to increase again after 14 months. He opted for treatment with sipuleucel-T, while continuing with the enzalutamide. This resulted in another complete PSA response 6 months after exposure to sipuleucel-T. CONCLUSION Sipuleucel-T typically does not produce significant PSA reductions, and, to the best of our knowledge, only 1 previous report of a durable complete PSA response in a patient with metastatic disease has been published. The timing of this response supports an immune mechanism. The biologic rationale for the combination, coupled with the clinical result observed in our patient, provides a basis for studies of the combination of sipuleucel-T and enzalutamide.

Interventions that may reduce depressive symptoms among prostate cancer patients: a systematic review and meta-analysis

Prostate cancer patients are at increased risk of depression yet there is no standard intervention to address this. The purpose of this meta‐analysis is to examine the efficacy of interventions in reducing depressive symptoms in men with prostate cancer.

Falls and Frailty in Prostate Cancer Survivors: Current, Past, and Never Users of Androgen Deprivation Therapy

To compare the prevalence of and association between falls and frailty of prostate cancer survivors (PCSs) who were current, past or never users of androgen deprivation therapy (ADT).

Open-label, multicenter, phase 1 study of alisertib (MLN8237), an aurora A kinase inhibitor, with docetaxel in patients with solid tumors

This study was designed to determine the safety, tolerability, and pharmacokinetics (PK) of alisertib (MLN8237) in combination with docetaxel and to identify a recommended dose for the combination.