Introduction of novel agents for the management of advanced prostate cancer provides a range of treatment options with notable benefits for men with metastatic castration-resistant prostate cancer ...(mCRPC). At the same time, understanding of optimal patient selection, effective sequential use, and development of resistance patterns remains incomplete.
To review current systemic therapies and recent advances in drug development for mCRPC and strategies to aid in patient selection and optimal sequencing.
A literature review of PubMed/Medline, Cochrane Library, Current Contents Medicine, Web of Science, Clinical Trial.Gov, WHO-ICTRP (January 2004–November 2017), and the proceedings of major international meetings (2015/2016/2017) was performed in November 2017.
In the last few years, several new options for treatment of mCRPC have shown a survival benefit in phase III trials besides docetaxel:abiraterone, enzalutamide, cabazitaxel, radium-223, and sipuleucel-T. Radium-223 and denosumab have increased options in management of bone metastases. Currently, novel agents such as next-generation androgen receptor (AR) axis-targeting treatments, immunotherapeutics, or therapies targeting other oncogenic and genomic pathways, particularly poly(adenosine diphosphate–ribose) polymerase (PARP) inhibitors and PD-1 inhibitors, are under clinical investigation. With increasing treatment options for mCRPC, information on how to personalize management and how to select and sequence existing therapies is beginning to emerge, as are predictive biomarkers (homologous repair mutations, mismatch repair mutations, AR splice variant 7). Finally, early use of active agents in the castration-sensitive state will likely also change the clinical management of the disease when it becomes castrate resistant.
The emergence of new drugs for mCRPC has improved treatment options dramatically. Currently, systemic treatment options for mCRPC include hormonal therapy, chemotherapy, immunotherapy, and radionuclide therapy as well as bone-modifying agents and palliative or supportive measures. Further, new genetically targeted agents (PARP inhibitors and PD-1 inhibitors) are on the horizon for certain subsets of biomarker-selected patients. The best strategies for patient selection and optimal sequential use to achieve the longest cumulative survival improvement and to prevent early resistance remain unclear.
The current literature and proceedings from relevant congresses related to available systemic agents for the treatment of metastatic castration-resistant prostate cancer, including novel genetically targeted therapies, including poly(adenosine diphosphate–ribose) polymerase inhibitors and PD-1 inhibitors, were reviewed. Current therapies and ongoing developments are discussed.
In the last few years, new therapeutics for the treatment of metastatic castration-resistant prostate cancer have increased survival substantially. While promising novel agents are currently under trial, including genetically targeted therapies (poly(adenosine diphosphate–ribose) polymerase inhibitors and PD-1 inhibitors), further clinical and translational research in predictive biomarkers is needed to optimize treatment selection and sequencing strategies for existing drugs.
Standard therapy for metastatic, hormone-sensitive prostate cancer is androgen-deprivation therapy, usually with docetaxel. A large, multinational, phase 3 trial assessed the addition of the ...androgen-receptor blocker darolutamide to standard therapy. At 4 years, survival was higher with darolutamide than with placebo (62.7% vs. 50.4%), with no major differences in the frequency of adverse events.
A randomized trial involving patients with metastatic prostate cancer whose disease progressed after receipt of docetaxel and hormonal therapy showed that cabazitaxel was superior to an ...androgen-signaling–targeted agent in extending imaging-based progression-free survival, overall survival, and PSA response.
In a trial, the median metastasis-free survival among men with nonmetastatic, castration-resistant prostate cancer and a short PSA doubling time was 36.6 months with enzalutamide and 14.7 months with ...placebo. Falls and heart problems were more common with enzalutamide.
Among men with high-risk, nonmetastatic, castration-resistant prostate cancer, the addition of enzalutamide to androgen-deprivation therapy improved overall survival by nearly a year as compared with ...ADT alone: median survival was 67 months with enzalutamide plus ADT and 56 months with ADT alone.
Summary Background Cabozantinib is an oral inhibitor of tyrosine kinases including MET, VEGFR, and AXL. The randomised phase 3 METEOR trial compared the efficacy and safety of cabozantinib versus the ...mTOR inhibitor everolimus in patients with advanced renal cell carcinoma who progressed after previous VEGFR tyrosine-kinase inhibitor treatment. Here, we report the final overall survival results from this study based on an unplanned second interim analysis. Methods In this open-label, randomised phase 3 trial, we randomly assigned (1:1) patients aged 18 years and older with advanced or metastatic clear-cell renal cell carcinoma, measurable disease, and previous treatment with one or more VEGFR tyrosine-kinase inhibitors to receive 60 mg cabozantinib once a day or 10 mg everolimus once a day. Randomisation was done with an interactive voice and web response system. Stratification factors were Memorial Sloan Kettering Cancer Center risk group and the number of previous treatments with VEGFR tyrosine-kinase inhibitors. The primary endpoint was progression-free survival as assessed by an independent radiology review committee in the first 375 randomly assigned patients and has been previously reported. Secondary endpoints were overall survival and objective response in all randomly assigned patients assessed by intention-to-treat. Safety was assessed per protocol in all patients who received at least one dose of study drug. The study is closed for enrolment but treatment and follow-up of patients is ongoing for long-term safety evaluation. This trial is registered with ClinicalTrials.gov , number NCT01865747. Findings Between Aug 8, 2013, and Nov 24, 2014, 658 patients were randomly assigned to receive cabozantinib (n=330) or everolimus (n=328). The median duration of follow-up for overall survival and safety was 18·7 months (IQR 16·1–21·1) in the cabozantinib group and 18·8 months (16·0–21·2) in the everolimus group. Median overall survival was 21·4 months (95% CI 18·7–not estimable) with cabozantinib and 16·5 months (14·7–18·8) with everolimus (hazard ratio HR 0·66 95% CI 0·53–0·83; p=0·00026). Cabozantinib treatment also resulted in improved progression-free survival (HR 0·51 95% CI 0·41–0·62; p<0·0001) and objective response (17% 13–22 with cabozantinib vs 3% 2–6 with everolimus; p<0·0001) per independent radiology review among all randomised patients. The most common grade 3 or 4 adverse events were hypertension (49 15% in the cabozantinib group vs 12 4% in the everolimus group), diarrhoea (43 13% vs 7 2%), fatigue (36 11% vs 24 7%), palmar-plantar erythrodysaesthesia syndrome (27 8% vs 3 1%), anaemia (19 6% vs 53 17%), hyperglycaemia (3 1% vs 16 5%), and hypomagnesaemia (16 5% vs none). Serious adverse events grade 3 or worse occurred in 130 (39%) patients in the cabozantinib group and in 129 (40%) in the everolimus group. One treatment-related death occurred in the cabozantinib group (death; not otherwise specified) and two occurred in the everolimus group (one aspergillus infection and one pneumonia aspiration). Interpretation Treatment with cabozantinib increased overall survival, delayed disease progression, and improved the objective response compared with everolimus. Based on these results, cabozantinib should be considered as a new standard-of-care treatment option for previously treated patients with advanced renal cell carcinoma. Patients should be monitored for adverse events that might require dose modifications. Funding Exelixis Inc.
In a recent phase 3 randomized trial of 700 patients with advanced urothelial cancer (JAVELIN Bladder 100; NCT02603432 ), avelumab/best supportive care (BSC) significantly prolonged overall survival ...relative to BSC alone as maintenance therapy after first-line chemotherapy. Exploratory biomarker analyses were performed to identify biological pathways that might affect survival benefit. Tumor molecular profiling by immunohistochemistry, whole-exome sequencing and whole-transcriptome sequencing revealed that avelumab survival benefit was positively associated with PD-L1 expression by tumor cells, tumor mutational burden, APOBEC mutation signatures, expression of genes underlying innate and adaptive immune activity and the number of alleles encoding high-affinity variants of activating Fcγ receptors. Pathways connected to tissue growth and angiogenesis might have been associated with reduced survival benefit. Individual biomarkers did not comprehensively identify patients who could benefit from therapy; however, multi-parameter models incorporating genomic alteration, immune responses and tumor growth showed promising predictive utility. These results characterize the complex biologic pathways underlying survival benefit from immune checkpoint inhibition in advanced urothelial cancer and suggest that multiple biomarkers might be needed to identify patients who would benefit from treatment.
Summary Background Abiraterone acetate improved overall survival in metastatic castration-resistant prostate cancer at a preplanned interim analysis of the COU-AA-301 double-blind, placebo-controlled ...phase 3 study. Here, we present the final analysis of the study before crossover from placebo to abiraterone acetate (after 775 of the prespecified 797 death events). Methods Between May 8, 2008, and July 28, 2009, this study enrolled 1195 patients at 147 sites in 13 countries. Patients were eligible if they had metastatic castration-resistant prostate cancer progressing after docetaxel. Patients were stratified according to baseline Eastern Cooperative Oncology Group (ECOG) performance status, worst pain over the past 24 h on the Brief Pain Inventory-Short Form, number of previous chemotherapy regimens, and type of progression. Patients were randomly assigned (ratio 2:1) to receive either abiraterone acetate (1000 mg, once daily and orally) plus prednisone (5 mg, orally twice daily) or placebo plus prednisone with a permuted block method via an interactive web response system. The primary endpoint was overall survival, analysed in the intention-to-treat population. This study is registered with ClinicalTrials.gov , number NCT00638690. Findings Of the 1195 eligible patients, 797 were randomly assigned to receive abiraterone acetate plus prednisone (abiraterone group) and 398 to receive placebo plus prednisone (placebo group). At median follow-up of 20·2 months (IQR 18·4–22·1), median overall survival for the abiraterone group was longer than in the placebo group (15·8 months 95% CI 14·8–17·0 vs 11·2 months 10·4–13·1; hazard ratio HR 0·74, 95% CI 0·64–0·86; p<0·0001). Median time to PSA progression (8·5 months, 95% CI 8·3–11·1, in the abiraterone group vs 6·6 months, 5·6–8·3, in the placebo group; HR 0·63, 0·52–0·78; p<0·0001), median radiologic progression-free survival (5·6 months, 5·6–6·5, vs 3·6 months, 2·9–5·5; HR 0·66, 0·58–0·76; p<0·0001), and proportion of patients who had a PSA response (235 29·5% of 797 patients vs 22 5·5% of 398; p<0·0001) were all improved in the abiraterone group compared with the placebo group. The most common grade 3–4 adverse events were fatigue (72 9% of 791 patients in the abiraterone group vs 41 10% of 394 in the placebo group), anaemia (62 8% vs 32 8%), back pain (56 7% vs 40 10%), and bone pain (51 6% vs 31 8%). Interpretation This final analysis confirms that abiraterone acetate significantly prolongs overall survival in patients with metastatic castration-resistant prostate cancer who have progressed after docetaxel treatment. No new safety signals were identified with increased follow-up. Funding Janssen Research & Development.
Atezolizumab, a humanised monoclonal antibody targeting PD-L1, is approved for locally advanced/metastatic urothelial carcinoma. SAUL evaluated atezolizumab in a broader, pretreated population, ...including patients ineligible for the pivotal IMvigor211 phase 3 trial of atezolizumab.
To determine the safety and efficacy of atezolizumab in an international real-world setting.
Between November 2016 and March 2018 (median follow-up 12.7mo), 1004 patients with locally advanced or metastatic urothelial or nonurothelial urinary tract carcinoma who experienced progression during or after one to three prior therapies for inoperable, locally advanced, or metastatic disease were enrolled. Patients with renal impairment, treated central nervous system metastases, or stable controlled autoimmune disease were eligible; 10% had Eastern Cooperative Oncology Group performance status (ECOG PS) 2 and 98% were platinum pretreated (Clinicaltrials.gov: NCT02928406).
Atezolizumab 1200mg every 3wk until progression or unacceptable toxicity.
The primary endpoint was safety. Secondary efficacy endpoints included overall survival (OS), progression-free survival (PFS), and overall response rate (ORR).
The median treatment duration was 2.8mo (range 0–19); 22% remained on treatment and 8% discontinued because of toxicity. Grade ≥3 adverse events occurred in 45% of patients. The most common grade ≥3 treatment-related adverse events were fatigue, asthenia, colitis, and hypertension (each in 1%). Median OS was 8.7mo (95% confidence interval CI 7.8–9.9). The 6-mo OS rate was 60% (95% CI 57–63%), median PFS was 2.2mo (95% CI 2.1–2.4), and the ORR was 13% (95% CI 11–16%; 3% complete responses). Among IMvigor211-like patients (excluding ECOG PS 2 and other IMvigor211 exclusion criteria), median OS was 10.0mo (95% CI 8.8–11.9) and 6-mo OS was 65% (95% CI 61–69%).
SAUL confirms the tolerability of atezolizumab in a real-world pretreated population with urinary tract carcinoma. Efficacy overall and in the IMvigor211-like subgroup is consistent with previous pivotal anti-PD-L1/PD-1 urothelial carcinoma trials. These results support the use of atezolizumab in urinary tract carcinoma, including patients with limited treatment options.
In this international study we investigated the efficacy and safety of atezolizumab treatment for advanced urinary tract cancer in a large population of pretreated patients, including those who would not normally be candidates for clinical trials. Patients tolerated the treatment well, even if they had autoimmune disease, were being treated with corticosteroids, or had disease that had spread to their brain. Life expectancy in this study for patients typical of everyday clinical practice was similar to that seen in trials that enrolled only selected fitter patients.
SAUL confirms the tolerability of atezolizumab in real-world patients with urinary tract carcinoma. Efficacy in the IMvigor211-like subgroup and the broader unselected population was consistent with previous anti-PD-L1/PD-1 pivotal trials, supporting the use of atezolizumab in these patients.
Androgen receptor (AR) signaling is a key pathway in prostate cancer, and patients are initially treated with androgen deprivation therapy. Patients who have stopped responding to androgen ...deprivation therapy are considered to have castration-resistant prostate cancer (CRPC), which is still dependent on AR signaling. Enzalutamide, an orally available AR inhibitor, was initially approved by the US FDA for the treatment of patients with metastatic CRPC who have previously received docetaxel. The indication was subsequently extended to include all patients with metastatic CRPC, and most recently to include patients with nonmetastatic CRPC. This review summarizes the body of evidence supporting enzalutamide efficacy and safety in CRPC.
PDF
