Prognostic Significance of Early Tumor Shrinkage Under Second-Line Targeted Therapy for Metastatic Renal Cell Carcinoma: A Retrospective Multi-Institutional Study in Japan

Current status of prognostic factors in patients with metastatic renal cell carcinoma

In recent years, the induction of novel agents, including molecular-targeted agents and immune checkpoint inhibitors, have dramatically changed therapeutic options and their outcomes for metastatic renal cell carcinoma. Several prognostic models based on the data of patients with metastatic renal cell carcinoma treated with targeted agents or cytokine therapy have been useful in real clinical practice. Serum or peripheral blood markers related to inflammatory response have been reported to be associated with their prognosis or therapeutic efficacy. In addition to them, investigation for novel predictive factors that represent the efficacy of agents, the risk of adverse events and the prognosis are required for the advance of therapeutic strategies. The present review discusses the conventional prognostic models and clinical factors, and recent advances of the identification of some of the most promising molecules as novel biomarkers for metastatic renal cell carcinoma.

Early tumor shrinkage as a predictive factor of metastatic renal cell carcinoma in molecular targeted therapy: A single institutional study

The aim of the present study was to investigate the impact of metastatic sites and early tumor shrinkage (eTS) as prognostic predictive factors of metastatic renal cell carcinoma (mRCC) in molecular targeted therapy. A total of 209 advanced RCC cases treated with sorafenib, sunitinib, axitinib, pazopanib, temsirolimus and everolimus from our single institution were included in the present study. Several known prognostic predictive factors, including metastatic sites and the rate of eTS, were analyzed by Kaplan-Meier survival estimate analysis followed by Cox's proportional hazards model analysis. eTS was measured by three independent physicians. Four metastatic sites in the liver, bone, lymph nodes and brain as well as greater eTS were identified as potential independent predictors of overall survival (OS) in several cohorts: i) Metastatic RCC (n=194); ii) metastatic clear cell RCC (n=119); and iii) mRCC patients with eTS data (n=127). In sub-analyses of patients treated with each 1st line tyrosine kinase inhibitor, eTS was identified as a potentially potent predictor of OS in patients treated with axitinib. The liver, bone, lymph nodes, brain metastases and eTS were identified as independent predictive factors of OS by analyzing a limited Japanese cohort.

Second-line treatment after sunitinib therapy in patients with renal cell carcinoma: a comparison of axitinib and mammalian target of rapamycin inhibitors

This retrospective study compared the outcomes of sequential therapy using sunitinib followed by axitinib or the mammalian target of rapamycin (mTOR) inhibitors (everolimus or temsirolimus). Among 234 patients treated with molecular-targeted drugs for metastatic renal cell carcinoma, we selected 137 patients treated with sunitinib as the first-line therapy. We then compared patients treated with axitinib (n = 52) or mTOR inhibitors (n = 31), as the second-line treatment, and investigated the progression-free survival (PFS) and overall survival (OS). The PFS of axitinib-treated patients (median 8.7 months) was superior to that of mTOR inhibitors-treated patients (median 3.4 months; P = 0.001). Additionally, the OS from baseline of axitinib-treated patients (median 69 months) was superior to that of mTOR inhibitors-treated patients (median 33.4 months; P = 0.034). A multivariate analysis was performed with the following factors: the drugs used for the second-line treatment, the Memorial Sloan Kettering Cancer Center risk classification during the initial treatment, whether the discontinuation of the first-line treatment was due to adverse events, and whether the duration of response of the first-line treatment was less than 6 or 12 months. Importantly, the drugs used for the second-line treatment and Memorial Sloan Kettering Cancer Center risk classification were independent factors. Our findings suggest that axitinib works better than mTOR inhibitors after the first-line treatment with sunitinib.

Pharmacogenetics-based area-under-curve model can predict efficacy and adverse events from axitinib in individual patients with advanced renal cell carcinoma

We investigated the relationship between axitinib pharmacogenetics and clinical efficacy/adverse events in advanced renal cell carcinoma (RCC) and established a model to predict clinical efficacy and adverse events using pharmacokinetic and gene polymorphisms related to drug metabolism and efflux in a phase II trial. We prospectively evaluated the area under the plasma concentration–time curve (AUC) of axitinib, objective response rate, and adverse events in 44 consecutive advanced RCC patients treated with axitinib. To establish a model for predicting clinical efficacy and adverse events, polymorphisms in genes including ABC transporters (ABCB1 and ABCG2), UGT1A, and OR2B11 were analyzed by whole-exome sequencing, Sanger sequencing, and DNA microarray. To validate this prediction model, calculated AUC by 6 gene polymorphisms was compared with actual AUC in 16 additional consecutive patients prospectively. Actual AUC significantly correlated with the objective response rate (P = 0.0002) and adverse events (hand-foot syndrome, P = 0.0055; and hypothyroidism, P = 0.0381). Calculated AUC significantly correlated with actual AUC (P < 0.0001), and correctly predicted objective response rate (P = 0.0044) as well as adverse events (P = 0.0191 and 0.0082, respectively). In the validation study, calculated AUC prior to axitinib treatment precisely predicted actual AUC after axitinib treatment (P = 0.0066). Our pharmacogenetics-based AUC prediction model may determine the optimal initial dose of axitinib, and thus facilitate better treatment of patients with advanced RCC.

Time to progression after first-line tyrosine kinase inhibitor predicts survival in patients with metastatic renal cell carcinoma receiving second-line molecular-targeted therapy

OBJECTIVES

The effect of response to first-line tyrosine kinase inhibitor (TKI) therapy on second-line survival in patients with metastatic renal cell carcinoma who receive second-line molecular-targeted therapy (mTT) after first-line failure remains unclear.

MATERIALS AND METHODS

Sixty patients who developed disease progression after first-line TKI, without prior cytokine therapy, were enrolled. According to the median first-line time to progression (1L-TTP), patients were divided into 2 groups (i.e., short vs. long). Second-line progression-free survival (2L-PFS) and second-line overall survival (2L-OS) were defined as the time from second-line mTT initiation. Survival was calculated with the Kaplan-Meier method and compared using the log-rank test between patients with short and long 1L-PFS. Predictors for survivals were identified using Cox proportional hazards regression models.

RESULTS

The median 1L-TTP was 8.84 months. Thirty patients (50.0%) with short 1L-TTP (<8.84mo) had significantly shorter 2L-PFS and 2L-OS compared to patients with long 1L-TTP (2L-PFS: 4.96 vs. 10.2mo, P = 0.0002; 2L-OS: 9.6 vs. 28.0mo, P = 0.0036). Multivariable analyses for 2L-PFS and 2L-OS showed that 1L-TTP was an independent predictor both as a categorical classification (cutoff: 8.84mo) and as a continuous variable (both P<0.05). The median follow-up duration was 13.1 months (interquartile range: 6.56-24.7).

CONCLUSIONS

Patients who achieve a long-term response after first-line TKI therapy could have a favorable prognosis with second-line mTT.

Effect of Systemic Inflammation on Survival in Patients With Metastatic Renal Cell Carcinoma Receiving Second-line Molecular-targeted Therapy

BACKGROUND

The role of systemic inflammatory markers, including C-reactive protein (CRP), the neutrophil/lymphocyte ratio (NLR), and the platelet/lymphocyte ratio (PLR), in predicting survival for patients with metastatic renal cell carcinoma receiving second-line molecular-targeted therapy (mTT) after first-line tyrosine kinase inhibitor failure remains unclear. Thus, we investigated the relationship between systemic inflammation and survival in such patients.

PATIENTS AND METHODS

Sixty-three patients were evaluated. Progression-free survival (PFS) and overall survival (OS) after second-line mTT initiation were evaluated according to the inflammatory marker levels. In addition, the prognostic factors for survival were examined.

RESULTS

The receiver operating characteristic curves for CRP, NLR, and PLR had areas under the curve of 0.779, 0.619, and 0.655, respectively; no significant differences were noted. The corresponding cutoff values were 0.48, 2.53, and 183. Patients with higher CRP (n = 40), NLR (n = 32), and PLR (n = 22) levels had significantly lower PFS and OS than those with lower CRP, NLR, and PLR levels. Multivariate analyses showed that CRP was the sole independent predictor for PFS and OS.

CONCLUSION

Systemic inflammation is associated with survival after second-line mTT. In particular, CRP was a strong independent predictive biomarker of prognosis.