Therapy For Metastatic Castration-resistant Prostate Cancer Research Articles

Abstract 984: Race- and ancestry-related metabolites and SNPs associated with response to secondary hormonal therapy in metastatic castration-resistant prostate cancer

Abstract The number of new cases and deaths from prostate cancer (PCa) is highest for Black men compared with other racial and ethnic groups, and Black PCa patients have a shorter average survival as well as a greater risk of tumor recurrence than men of other racial and ethnic groups. However, recent studies have shown that Black PCa patients have a better response to certain therapeutic regimens than White PCa patients. This study focuses on addressing the critical need to determine novel relationships between ancestry-related genetic variation and PCa aggressiveness and response to secondary hormonal therapy in metastatic castration-resistant PCa (mCRPC). We conducted correlative science in a DoD Prostate Cancer Clinical Trials Consortium (PCCTC) prospective multicenter study of secondary hormonal therapy in mCRPC stratified by race, Abi Race. This study enrolled 50 self-reported Black and 50 self-reported White mCRPC patients, and such patients received abiraterone and prednisone until disease progression or adverse event. We performed metabolic profiling using serum samples from fasting patients at baseline and after treatment. In addition, we performed genome-wide genotyping using genomic DNA from whole blood specimens from patients at baseline. We then identified race- and ancestry-related metabolite and SNP variations that associated with outcome using a penalized Cox model approach. In addition, we used Ingenuity Pathway Analysis (IPA) and Lasso Analysis to further study race-related metabolites and SNPs. From these analyses, we identified sphingolipids such as ceramide as race-related metabolites associated with outcome as well as SNPs in Sphingosine Kinase Type 1-Interacting Protein (SKIP) associated with outcome. In addition, our analyses suggest that sphingolipids such as ceramides and SKIP may regulate cancer-related biofunctions differently in Black and White mCRPC patients undergoing abiraterone treatment. Both sphingolipids and SKIP are components of the Sphingosine Rheostat, the regulatory component of sphingolipid cellular metabolism often exploited by various cancers, in which ceramides displays a pro-apoptotic role whereas sphingosine-1-phosphate (S1P) is associated with an anti-apoptotic role and is indirectly regulated by SKIP via regulating the activity of Sphingosine Kinase (SPK1). Evaluation of the function of these sphingolipids and SKIP in PCa cell drug response and aggressiveness are currently underway. These findings are furthering understanding of race- and ancestry-related biological factors that influence response to secondary hormonal therapy in mCRPC and have the potential to impact selection of patients for secondary hormonal therapy and to mitigate PCa disparity. Citation Format: Sean Alan Piwarski, Tyler Allen, Bonnie LaCroix, Lauren Howard, Morgan Paul, Nick Bachelder, Alex Sibley, Steve Patierno, Terry Hyslop, Kouros Owzar, Daniel George, Jennifer Freedman. Race- and ancestry-related metabolites and SNPs associated with response to secondary hormonal therapy in metastatic castration-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 984.

MicroRNA-34a, Prostate Cancer Stem Cells, and Therapeutic Development.

Simple SummaryProstate cancer is still the most common cancer among men in the US. Current standard-of-care therapies for metastatic castration-resistant prostate cancer can offer survival benefits measured only in months. The patients eventually develop drug resistance and tumor relapse. There is strong evidence that during treatment, prostate cancer stem cells may become the predominant population within tumor bulk, and function as the “root cause” for drug resistance. microRNA-34a, a bona fide tumor-suppressive miRNA, represents a potent cancer stem cell suppressor by targeting many molecules essential for cancer stem cell survival. This article will review the tumor suppressive role of miRNA-34a in prostate cancer, and its therapeutic development strategies for advanced prostate cancer patients.Prostate cancer (PCa) is a highly heterogeneous disease and typically presents with multiple distinct cancer foci. Heterogeneity in androgen receptor (AR) expression levels in PCa has been observed for decades, from untreated tumors to castration-resistant prostate cancer (CRPC) to disseminated metastases. Current standard-of-care therapies for metastatic CRPC can only extend life by a few months. Cancer stem cells (CSCs) are defined as a subpopulation of cancer cells that exists in almost all treatment-naive tumors. Additionally, non-CSCs may undergo cellular plasticity to be reprogrammed to prostate cancer stem cells (PCSCs) during spontaneous tumor progression or upon therapeutic treatments. Consequently, PCSCs may become the predominant population in treatment-resistant tumors, and the “root cause” for drug resistance. microRNA-34a (miR-34a) is a bona fide tumor-suppressive miRNA, and its expression is dysregulated in PCa. Importantly, miR-34a functions as a potent CSC suppressor by targeting many molecules essential for CSC survival and functions, which makes it a promising anti-PCSC therapeutic. Here, we conducted a comprehensive literature survey of miR-34a in the context of PCa and especially PCSCs. We provided an updated overview on the mechanisms of miR-34a regulation followed by discussing its tumor suppressive functions in PCa. Finally, based on current advances in miR-34a preclinical studies in PCa, we offered potential delivery strategies for miR-34a-based therapeutics for treating advanced PCa.

Cell-free DNA profiling of metastatic prostate cancer reveals microsatellite instability, structural rearrangements and clonal hematopoiesis

BackgroundThere are multiple existing and emerging therapeutic avenues for metastatic prostate cancer, with a common denominator, which is the need for predictive biomarkers. Circulating tumor DNA (ctDNA) has the potential to cost-efficiently accelerate precision medicine trials to improve clinical efficacy and diminish costs and toxicity. However, comprehensive ctDNA profiling in metastatic prostate cancer to date has been limited.MethodsA combination of targeted and low-pass whole genome sequencing was performed on plasma cell-free DNA and matched white blood cell germline DNA in 364 blood samples from 217 metastatic prostate cancer patients.ResultsctDNA was detected in 85.9% of baseline samples, correlated to line of therapy and was mirrored by circulating tumor cell enumeration of synchronous blood samples. Comprehensive profiling of the androgen receptor (AR) revealed a continuous increase in the fraction of patients with intra-AR structural variation, from 15.4% during first-line metastatic castration-resistant prostate cancer therapy to 45.2% in fourth line, indicating a continuous evolution of AR during the course of the disease. Patients displayed frequent alterations in DNA repair deficiency genes (18.0%). Additionally, the microsatellite instability phenotype was identified in 3.81% of eligible samples (≥ 0.1 ctDNA fraction). Sequencing of non-repetitive intronic and exonic regions of PTEN, RB1, and TP53 detected biallelic inactivation in 47.5%, 20.3%, and 44.1% of samples with ≥ 0.2 ctDNA fraction, respectively. Only one patient carried a clonal high-impact variant without a detectable second hit. Intronic high-impact structural variation was twice as common as exonic mutations in PTEN and RB1. Finally, 14.6% of patients presented false positive variants due to clonal hematopoiesis, commonly ignored in commercially available assays.ConclusionsctDNA profiles appear to mirror the genomic landscape of metastatic prostate cancer tissue and may cost-efficiently provide somatic information in clinical trials designed to identify predictive biomarkers. However, intronic sequencing of the interrogated tumor suppressors challenges the ubiquitous focus on coding regions and is vital, together with profiling of synchronous white blood cells, to minimize erroneous assignments which in turn may confound results and impede true associations in clinical trials.

Evaluation of cabazitaxel's toxicity and tolerance: AC Camargo Cancer Center experience.

e566 Background: Cabazitaxel is an approved second-line treatment in metastatic castration-resistant prostate cancer therapy with a significant survival benefit compared to mitoxantrone. There are few data about cabazitaxel's toxicity in patients not selected. Objective: Evaluate the efficacy and toxicity among younger (< 70 years) and older (> 70 years) population. Methods: We selected 62 patients with metastatic castration resistant prostate cancer treated in AC Camargo Cancer Center from January 2011 to July 2015. 58 patients fulfilled the study criteria: diagnosis of adenocarcinoma prostate cancer, at least one session of cabazitaxel, with more than 18 years old. Results: We had in our sample 33 patients less than 70 years and 25 over 70 years. The initial dose of cabazitaxel was 25 mg/m2 in 75.8% of patients < 70 years and 52% in > 70 years patients. The use of granulocytics growing factor was observed in 64% of the older patients and more than 80% of this indication was in primary profilaxis. There were five deaths associated to the treatment, 4 lung infection and 1 kidney failure. The worst grade of adverse event up to 30 days after last administration was grade 2, including hematological and non-hematological events, both with no statistical significance between the groups. However, there was a greater number of febrile neutropenia in elderly people (28% versus 6%) with a statistical significance between < 70 e > 70 years (p 0.031). OS was 13,7 months (IC 9.16 – 18.2) and PFS was 4,6 months (IC 3.43 – 5.73). OS among the two groups was lower in < 70 years reaching 9,3 months (IC 2.06-16.5) versus 22.2 months (IC 4.86-39.50 ), p= 0.073. As well, PFS in < 70 years was 3.8 months (IC 3.26-4.36) versus 4.6 months (IC 2.4-14.1), p = 0.02. Conclusions: Treatment with cabazitaxel is tolerable, with manageable adverse events in a real-world patient population. In our cohort, elderly population (> 70 years) had more febrile neutropenia, suggesting dose reduction in this population, indication of granulocytic growing factor as primary profilaxis, close monitoring, and adequate patient counseling.

Radium-223 Outcomes After Multiple Lines of Metastatic Castration–Resistant Prostate Cancer Therapy in Clinical Practice: Implication of Pretreatment Spinal Epidural Disease

Radium-223 Outcomes After Multiple Lines of Metastatic Castration–Resistant Prostate Cancer Therapy in Clinical Practice: Implication of Pretreatment Spinal Epidural Disease

Radium-223 outcomes after multiple lines of metastatic castration-resistant prostate cancer therapy in clinical practice: implication of pre-treatment spinal epidural disease.

Magnetic resonance imaging (MRI) is not routinely performed before initiating radium-223 to document spinal epidural disease. However, radium-223 decays to form α-particles with very short path lengths that may not reach the epidural space. Herein, we investigate the impact of baseline spinal epidural disease on metastatic castration-resistant prostate cancer (mCRPC) patients treated with radium-223. Between October 2013 to December 2014, 41 consecutive mCRPC patients at a large tertiary cancer center were prescribed radium-223 as part of standard of care. 29% of patients had pre-treatment epidural disease (posMRI), 27% had no epidural disease (negMRI), and 44% did not have a baseline MRI (noMRI). All patients had post-treatment spinal imaging. Actuarial survival times were calculated for overall survival (OS), spinal axis radiographic progression-free survival (spinePFS) and epidural progression-free survival (epiPFS) from time of first radium-223 treatment. For patients with posMRI (n=12), noMRI (n=18) and negMRI (n=11) cumulative rates of development or worsening of epidural disease and/or high-grade cord compression at time of last follow-up were 83%, 44% and 9%, respectively (P=0.001). For the posMRI, noMRI and negMRI groups the median OS was 6.3 months, 12.6 months and not reached (P=0.01), the median spinePFS was 3.2 months, 4.8 months and not reached (P=0.01), and the median epiPFS was 3.2 months, 10.4 months and not reached (P=0.001). Completing less than six cycles of radium-223 was significantly associated with worse OS (P<0.0001), spinePFS (P=0.007) and epiPFS (P=0.01). Greater than or equal to twenty osseous lesions pre-treatment was significantly associated with worse spinePFS (P=0.001) and epiPFS (P=0.03). In a heavily pre-treated small cohort, patients with baseline epidural disease frequently progressed to spinal cord compression and early cessation of radium-223 therapy. Studies are needed to determine the optimal timing of radium-223 with other mCRPC therapies given the predilection for epidural disease and treatment failure after multiple prior lines of mCRPC therapy.

State-of-the-Art Management for the Patient with Castration-Resistant Prostate Cancer in 2012

Much progress has been made in metastatic castration-resistant prostate cancer (CRPC), and multiple new U.S. Food and Drug Administration (FDA)-approved survival-prolonging drugs are now available. In 2004, docetaxel/prednisone was the first therapy shown to prolong survival. In 2010 and 2011, sipuleucel-T, cabazitaxel/prednisone, and abiraterone/prednisone were FDA approved. Two new agents, radium-223 and MDV-3100, have recently reported large phase III trials prolonging overall survival and will be submitted for regulatory approval in 2012. One can now begin to ask, is there an optimal sequence for therapies in metastatic CRPC? Despite the recent progress, there is much we do not know and virtually no information on this important question. We know that abiraterone/prednisone and cabazitaxel/prednisone are appropriate choices for a patient after receiving docetaxel, but we do not know what, if anything, represents the optimal sequence for abiraterone and cabazitaxel. In fact we do not understand how one therapy may affect the response to a subsequent therapy. We are also aware that the pre- and postdocetaxel spaces represent regulatory rather than biologic divisions. In addition, despite the proven role of docetaxel/prednisone, many patients with CRPC are not considered to be suitable for chemotherapy, and worldwide many never receive any form of chemotherapy. What is the optimal management for these patients? Taken together it is reasonable to assess patient preferences, prior therapies and response/tolerance to prior therapies, burden of disease, comorbidities, current symptoms, drug toxicities, out-of-pocket costs, etc., in clinical decision making. Given the many factors we do not know, it is hard to be dogmatic in approaching the therapeutic options for the patient with CRPC. We will likely soon move beyond the current sequencing paradigm and begin to assess new combinations in a systematic and rational fashion. Perhaps one day, in the not too distant future, we will develop molecular "stratification systems" to better guide therapeutic choices in CRPC.

Using Surrogate Biomarkers to Predict Clinical Benefit in Men with Castration-Resistant Prostate Cancer: An Update and Review of the Literature

Recurrent prostate cancer has a complex molecular etiology and a prolonged disease course. Although initially responsive to androgen ablation, many men eventually become castration resistant, develop skeletal metastases, and are palliatively treated with docetaxel-based chemotherapy, radiation therapy, bisphosphonates, and best supportive care. Given the modest success rates of the current standard of care, clinical trial enrollment is encouraged. Castration-resistant prostate cancer (CRPC) is a heterogeneous disease, both in clinical manifestations and outcomes, requiring an individualized approach to both patient care and trial design. Herein, we review surrogate markers of disease progression and treatment efficacy in advanced prostate cancer in light of recently published guidelines that have redefined eligibility, response criteria, and suitable endpoints in prostate cancer drug development. The guidelines have refined outcome measures to potentially better capture clinical benefit and the ability of novel targeted molecular and biologic agents to impact favorably on this disease. We consider prostate-specific antigen changes, circulating tumor cells, bone scan alterations, markers of bone metabolism (urinary N-telopeptide and bone-specific alkaline phosphatase), pain improvements, and progression-free survival. To illustrate the role and challenges of these potential biomarkers and endpoints in drug development, we discuss a class of novel molecularly targeted agents, the src kinase inhibitors. Given that there are currently no validated surrogate markers of overall survival for assessing early clinical benefit from systemic therapy in metastatic CRPC, incorporation of relevant biomarkers into all phases of clinical development is essential to accelerate drug development in this field.

Results of a phase II study of picoplatin with docetaxel and prednisone in first-line treatment of castration-resistant prostate cancer (CRPC)

5140 Background: Picoplatin (Pico) was designed to overcome platinum resistance and has the potential for improved safety compared to other platinum agents. Previously, a PSA response rate of 25% was observed when Pico monotherapy was infused at 120 mg/m2 Q3W (N = 20). Recently, a 34-patient Phase I study was performed to investigate the safety and efficacy of Pico in combination with docetaxel (D) + prednisone (pred) as first-line therapy for metastatic CRPC. Picoplatin therapy was well-tolerated at a dose of 120 mg/m2 and 19 of 32 evaluable pts (59%) achieved a confirmed PSA response. Methods: 32 patients with chemotherapy-naïve CRPC and disease progression received Pico (120 mg/m2) and D (75 mg/m2) Q3W with pred 5 mg po bid for up to 10 cycles. PSA responses were defined as a reduction from baseline of at least 50% maintained for at least 4 weeks. CT and bone scans were also evaluated. Tumor response was measured using RECIST. Results: Patients received a median of 10 cycles (range = 1–10). Median baseline PSA was 340.8 ng/mL (range 5.6–3019). One pt had no baseline PSA data. Of the 24 patients with evaluable post-treatment PSA, 83% (95% CI 64–93%) had PSA decreases &lt;50% of baseline, and in 8 of these (33% of the evaluable population), PSA reached normal levels (&lt; 4 ng/mL). In the intent-to-treat population, the PSA response rate was 63% (95% CI 45–77%). 13 patients evaluated by CT scan had measurable disease; 6 pts had SD by RECIST, 4 had PD, and 3 were not evaluable. The most common adverse events were alopecia (36%), asthenia (32%), neutropenia (29%), increased creatinine (23%), and thrombocytopenia (19%). No neurotoxicity ≥ grade 2 was observed. Conclusions: Picoplatin was safely administered to patients with CRPC as 1st-line therapy at 120 mg/m2 Q3W with full doses of docetaxel and prednisone, resulting in a PSA response rate of 83% of evaluable patients. These results support further development of picoplatin as a novel combination with docetaxel for the treatment of CRPC. [Table: see text]