The 2016 Genitourinary Cancers Symposium was held earlier this month in San Francisco. Abstracts and presentations included data and discussion on the latest strategies in the prevention, screening, diagnosis, and treatment of prostate, kidney, testicular, and urothelial cancers. Snapshots of data from some of the many studies presented are provided here. Further data and full coverage of the abstracts will be reported in upcoming issues of The ASCO Post. For interviews with experts conducted live at the meeting, visit video.ascopost.com.
Metastatic Testicular Germ Cell Tumors
Among patients with poor-risk metastatic testicular germ cell tumors, those treated with first-line curative therapy who survive (and remain disease-free) for more than 2 years experience risk-of-relapse rates and survival times similar to those of favorable- or intermediate-risk patients.
Such were the findings of a large multi-institutional study of patients with metastatic testicular germ cell tumors treated with first-line curative therapy from 1990 to 2012, presented by Ko et al.1 The study evaluated how initial risk changes over time for those who survived since curative treatment, a concept referred to as conditional survival. Findings from the study indicated that in patients with metastatic testicular germ cell tumors, those who survive for more than 2 years disease-free will likely remain alive in subsequent years.
Advanced Renal Cell Carcinoma
New analyses from a phase III clinical trial of patients with previously treated advanced renal cell carcinoma demonstrated that patients of all risk levels experience more benefit from cabozantinib (Cometriq), a small-molecule inhibitor of the tyrosine kinases c-MET and VEGFR2, than from the current standard of care, everolimus (Afinitor). The greater activity of cabozantinib was independent of the number of metastatic sites, number of prior treatments, and type of treatments administered.2
Early findings from the first 375 patients showed that cabozantinib improved the median progression-free survival compared to everolimus (7.4 vs 3.8 months). The new analysis of data from all 658 patients showed that 75% of patients treated with cabozantinib experienced tumor shrinkage, compared to 48% of everolimus-treated patients. Researchers found that progression-free survival improvements associated with cabozantinib vs everolimus were consistent across patient subgroups such as risk category, tumor burden, and prior therapy.
Treatment Decision-Making in Prostate Cancer
An early study suggests that an experimental blood test may help aid in treatment selection for patients with prostate cancer.3 Investigators indicated that the liquid biopsy enables characterization of the heterogeneity of circulating tumor cells. Heterogeneity score was associated with response to treatment with enzalutamide (Xtandi) or abiraterone acetate (Zytiga), both androgen receptor–directed therapies. The score was not correlated with response to taxanes.
Metastatic Urothelial Cancer
In the pivotal phase II IMvigor 210 study, the investigational cancer immunotherapy atezolizumab produced durable and improved response rates in patients with locally advanced or metastatic urothelial carcinoma, according to data presented by Hoffman-Censits et al.4 Atezolizumab is a monoclonal antibody against programmed cell death ligand 1 (PD-L1).
In the study, patients whose tumors showed high levels of PD-L1 expression had a median overall survival time of 11.4 months, while for the overall study population, median overall survival was 7.9 months. Moreover, the results showed that 84% of patients who responded to atezolizumab continued to show a benefit over almost 12 months of follow-up, regardless of their PD-L1 status.
Phase III trials of atezolizumab are ongoing in metastatic urothelial cancer. ■
Disclosure: For full disclosures of the study authors, view the abstracts at meetinglibrary.asco.org.
1. Ko JJ, et al: Conditional survival of patients with metastatic testicular germ cell tumours treated with first-line curative therapy. 2016 Genitourinary Cancers Symposium. Abstract 472. Presented January 8, 2016.
2. Escudier BJ, et al: Subgroup analyses of METEOR, a randomized phase 3 trial of cabozantinib vs everolimus in patients with advanced renal cell carcinoma. 2016 Genitourinary Cancers Symposium. Abstract 499. Presented January 9, 2016.
3. Scher H, et al: Single CTC characterization to identify phenotypic and genomic heterogeneity as a mechanism of resistance to AR signaling directed therapies in mCRPC patients. 2016 Genitourinary Cancers Symposium. Abstract 163. Presented January 7, 2016.
4. Hoffman-Censits JH, et al: IMvigor 210, a phase II trial of atezolizumab in platinum-treated locally advanced or metastatic urothelial carcinoma. 2016 Genitourinary Cancers Symposium. Abstract 355. Presented January 8, 2016.