Progression-free survival as a surrogate endpoint of overall survival in patients with metastatic renal cell carcinoma

Predicting overall survival benefit in previously untreated, unresectable or metastatic melanoma from improvement in progression-free survival: a correlation meta-analysis

Objectives

To evaluate the association between the treatment effects on progression-free survival (PFS) and overall survival (OS) for previously untreated, unresectable or metastatic melanoma.

Methods

A systematic literature review identified eligible trials reporting PFS and OS. Bivariate random effects meta-analysis (BRMA) was performed to estimate the correlation between the hazard ratios (HRs) of OS (HROS) and PFS (HRPFS), and sample size-weighted linear regression (WLR) was used to estimate a surrogacy equation which predict the HROS from the HRPFS. Strength of the correlation obtained from BRMA and WLR models was assessed using published guidelines. Predictive performance of the WLR model was also evaluated internally by leave-one-out cross-validation (LOOCV) and externally against data from newly published trials. Further analyses included adjustments for BRAF mutation status, and restriction to phase III trials or trials evaluating immune checkpoint or BRAF/MEK inhibitors, without crossover or crossover-adjusted, or meeting proportional hazards assumption.

Results

BRMA and WLR estimated a correlation of 0.74 (95%CI: 0.51-0.87) and 0.81 (95%CI: 0.58-0.92), respectively. The estimated surrogacy equation derived from the WLR was lnHROS = -0.05 + 0.50 × lnHRPFS with a statistically non-significant intercept (95% CI: -0.14 - 0.03) and a statistically significant slope (95% CI: 0.35 - 0.65). The surrogacy equation derived from the BRMA was lnHROS = -0.11 + 0.36 × lnHRPFS with a statistically non-significant intercept (95% CI: -0.23 - 0.00) and a statistically significant slope (95% CI: 0.17 - 0.57). The predictive accuracy of the WLR was 95.8% in LOOCV. Across sensitivity analyses correlations between HRPFS and HROS were ≥0.77 and ≥0.85 based on BRMA and WLR, respectively, and the accuracy of the WLR model in LOOCV was ≥88%. When predicting HROS for newly published trials, the differences between the observed and model-predicted HROS's were <0.05.

Conclusions

Results suggest a clinically meaningful and moderate trial-level correlation between PFS and OS across all analyses. The analyses and high accuracy of the surrogacy equations shown in internal and external validations can enable earlier prediction of treatment effects on OS from the improvements on PFS for previously untreated unresectable or metastatic melanoma.

Ambulatory Routine Care in Oncology in Germany: Real-World Survival Data

INTRODUCTION

Survival data reported by randomised controlled trials are collected in a highly selected patient population and can thus only be transferred to a limited extent to real-world patients: the patients in routine care are mostly older, present with more comorbidities and a worse general state of health. This so-called efficacy-effectiveness gap typically results in inferior survival data in routine healthcare.

METHODS

Six prospective clinical tumour registries recruited a total of 11,679 patients receiving systemic therapy in haemato-oncological practices in Germany between 2006 and 2020. For these patients with advanced colorectal cancer, breast cancer, lung cancer, pancreatic cancer, renal cell cancer, and lymphatic neoplasms, overall survival was analysed. A comprehensive literature search was performed to identify suitable pivotal randomised controlled trials.

RESULTS

Median overall survival of patients treated in German routine care, with advanced colorectal, breast, lung, and pancreatic cancer, as well as with diffuse large B-cell lymphoma and multiple myeloma, is not shorter than the respective survival data reported in trials. Patients with advanced renal cell carcinoma, chronic lymphocytic leukaemia, or indolent non-Hodgkin lymphoma showed slightly lower survival rates compared to clinical trials.

CONCLUSIONS

Despite less favourable patient characteristics, survival data from patients with cancer treated in ambulatory routine care in Germany are in range with results from randomised controlled studies.

Urinary miRNAs Predict Metastasis in Patients With Clinically Localized Clear Cell Renal Cell Carcinoma Treated With Nephrectomy

PURPOSE

Patients with clear cell renal cell carcinoma (ccRCC) might develop metastasis after surgery with curative intent. We aimed to characterize the expression levels of microRNAs in the urine (UmiRNAs) of patients before and after nephrectomy to determine the impact of UmiRNAs expression in the emergence of metastases.

METHODS

We prospectively collected pre- and post-nephrectomy urine samples from 117 patients with clinically localized and locally advanced ccRCC. UmiRNAs were extracted, purified, and measured using RT-PCR. Relative quantifications (RQ) of 137 UmiRNAs were calculated through 2-∆∆ method. The post-surgery/pre-surgery RQs ratio represented the magnitude of the expression levels of the UmiRNAs. The association of UmiRNA expression and the development of distant metastases was tested with Cox regression model.

RESULTS

Five UmiRNAs (miR-191-5p, miR-324-3p, miR-186-5p, miR-93-5p, miR-30b-5p) levels were upregulated before nephrectomy (p < .05). This conferred a 2- to 4-fold increased risk of metastasis, with miR-191-5p showing the most significant association with this endpoint (HR = 4.16, 95% CI = 1.38-12.58, p = .011). In a multivariate model stratified with stage and Fuhrman grade, we found that miR-191-5p, miR-324-3p, and miR-186-5p exhibited a strong association with metastasis development in patients with pathological T3 (pT3) tumors. Enrichment analysis with the most differentially expressed UmiRNAs showed that these UmiRNAs targeted genes that regulate cell survival and proliferation.

CONCLUSION

Our study indicated UmiR-191-5p, UmiR-324-3p, and UmiR-186-5p are potential markers to predict the development of metastasis, particularly in pT3 patients.

PATIENT SUMMARY

We compared changes of UmiRNAs expression detected pre- and postnephrectomy of patients with ccRCC. Our findings suggest that UmiRNA expression likely reflects tumor-specific changes that can be promising to predict the metastasis development, particularly in patients with non-metastatic locally advanced ccRCC. If confirmed, these findings may be useful for surveillance protocols for adjuvant therapy protocols.

A Surrogate Endpoint for Overall Survival in Locally Advanced and Resectable Esophageal Squamous Cell Carcinoma: A Reanalysis of Data From the NEOCRTEC5010 Trial

PURPOSE

This study aimed to investigate disease-free survival (DFS) as a surrogate endpoint for overall survival (OS) in patients with locally advanced and resectable esophageal squamous cell carcinoma.

METHODS AND MATERIALS

We re-analyzed patient data from the NEOCRTEC5010 randomized controlled trial (N = 451 patients) to compare their OS with that of an age- and sex-matched cohort from the general population of China. We used expected survival and the standardized mortality ratio, respectively, in our analysis of data collected from a neoadjuvant chemoradiation therapy (NCRT) plus surgery group and a surgery-only group. Published data from 6 randomized controlled trials and 20 retrospective studies were used to examine the correlation between DFS and OS at the trial level.

RESULTS

The annual hazard rate of disease progression decreased to 4.9% and 8.1% within 3 years in the NCRT and surgery groups, respectively. Patients who were disease-free at 36 months had a 5-year OS of 93.9% (95% CI, 89.7%-98.4%) in the NCRT group with a standardized mortality ratio of 1.1 (95% CI, 0.7-1.8; P = .5639). In contrast, the 5-year OS was only 12.9% (95% CI, 7.3%-22.6%) for patients in the NCRT group who exhibited disease progression within 36 months. At the trial level, DFS and OS were correlated with treatment effect (R2 = 0.605).

CONCLUSIONS

Disease-free status at 36 months is a valid surrogate endpoint for 5-year OS in patients with locally advanced and resectable esophageal squamous cell carcinoma. Patients who were disease-free at 36 months showed a favorable OS, which was indistinguishable from that of the age- and sex-matched comparison group from the general population; otherwise, their 5-year OS was extremely poor.

Association between age and efficacy of first-line immunotherapy-based combination therapies for mRCC: a meta-analysis

Aim: To compare the efficacy of first-line immune checkpoint inhibitor (ICI)-based combinations in metastatic renal cell carcinoma (mRCC) patients stratified by chronological age. Methods: According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, hazard ratios for overall survival (OS) from randomized controlled trials were synthesized. Results: Five RCTs were eligible for meta-analyses. ICI-based combinations significantly improved OS compared with sunitinib alone, both in younger (<65 years) and older (≥65 years) patients, whereas the OS benefit was significantly better in younger patients (p = 0.007). ICI-based combinations did not improve OS in patients aged ≥75 years. Treatment rankings showed age-related differential recommendations regarding improved OS. Conclusion: OS benefit from first-line ICI-based combinations was significantly greater in younger patients. Age-related differences could help enrich shared decision-making.

Clinical presentation, treatment patterns, and outcomes of colorectal cancer patients at Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia: A prospective cohort study

BACKGROUND

Colorectal cancer (CRC) is the third most common cause of cancer death in both genders worldwide.

AIMS

This study aimed to evaluate the outcomes and prognostic factors of CRC patients at Tikur Anbessa Specialized Hospital in Ethiopia.

METHODS AND RESULTS

A prospective cohort study was conducted on 209 patients from January 2020 to September 2022. Kaplan-Meier curves and bivariate and multivariate Cox regression analyses were used to analyze overall and progression-free survival, with a significance value of P < .05. Results showed an overall mortality rate was 67.46% (95% confidence interval [CI]: 61.0-74.0), while the 1-year overall survival (OS) rate was 63.16% (95% CI: 56.23-69.29), with a median follow-up duration of 20 months. The median OS and progression-free survival times were 17 and 11 months, respectively. Age above 40 years (hazard ratio [HR] = 1.53, 1.02-2.29, p < .040), lower educational level (high school and below) (HR = 2.20, 1.24-3.90, p < .007), poor performance status (HR = 1.60, 1.03-2.48, p < .035), Hgb ≤12.5 g/dL (HR = 1.55, 1.03-2.08, p < .035), T-4 disease (HR = 6.05, 2.28-16.02, p < .000), and metastases at diagnosis (HR = 8.53, 3.77-19.25, p < .000) were all associated with poorer survival.

CONCLUSION

These findings suggest that poor survival of CRC patients in Ethiopia is largely due to advanced stage of the disease and lack of timely treatment, and highlight the urgent need for improved access to cancer treatment in the region.

Progression-free survival as surrogate endpoint of overall survival in esophageal squamous cell carcinoma: a real-world data and literature-based analysis

Background

The surrogacy of progression-free survival (PFS) for overall survival (OS) in esophageal squamous cell carcinoma (ESCC) remains unelucidated. This study aimed to determine the validity of PFS as a surrogate endpoint for OS in ESCC patients treated with definitive radiotherapy or definitive chemoradiotherapy (dRT/dCRT), as well as characterize the prognostic factors and survival of such patients.

Methods

A total of 3662 patients from 10 cancer centers were enrolled. One-, 2-, and 3-year PFS (PFS12, PFS24, and PSF36, respectively) were used as time points for analysis. At each time point, ESCC-specific mortality and OS were characterized using competing risk and conditional survival models, while correlation between PFS and OS was evaluated by linear regression.

Results

At PFS12, PFS24, and PFS36, a progressive decrease in 5-year ESCC-specific mortality (35.2%-13.4%) and increase in 5-year OS (46.6%-62.9%) were observed. Regardless, the OS of patients remained markedly lower than those of the age- and sex-matched Chinese general population. TNM stage remained a significant prognostic factor at PFS36. Strong correlation was found between 3-year PFS and 5-year OS, which was further externally validated.

Conclusions

Three-year PFS may act as a potential surrogate endpoint for 5-year OS. TNM stage was considered a significant prognostic factor for OS, and may represent the optimal prognostic tool to guide clinical decision-making and post-treatment follow-up.

Analysis of a Real-World Progression Variable and Related Endpoints for Patients with Five Different Cancer Types

INTRODUCTION

We previously demonstrated that real-world progression (rwP) can be ascertained from unstructured electronic health record (EHR)-derived documents using a novel abstraction approach for patients with advanced non-small cell lung cancer (base case). The objective of this methodological study was to assess the reliability, clinical relevance, and the need for disease-specific adjustments of this abstraction approach in five additional solid tumor types.

METHODS

Patients with metastatic breast cancer (mBC), advanced melanoma (aMel), small cell lung cancer (SCLC), metastatic renal cell carcinoma (mRCC), and advanced gastric/esophageal cancer (aGEC) were selected from a real-world database. Disease-specific additions to the base case were implemented as needed. The resulting abstraction approach was applied to each disease cohort to capture rwP events and dates. To provide comprehensive clinical context, real-world progression-free survival (rwPFS) and time to progression (rwTTP) were compared to real-world overall survival (rwOS), time to next treatment (rwTTNT), and time to treatment discontinuation (rwTTD). Endpoint estimates were assessed using the Kaplan-Meier method. Correlations between real-world endpoints and rwOS were calculated using Spearman's ρ.

RESULTS

Additions to the base-case rwP abstraction approach were required for mBC, aMel, and SCLC. Inter-abstractor agreement for rwP occurrence, irrespective of date, ranged from 88% to 97%. Occurrence of clinically relevant downstream events (new antineoplastic systemic therapy start, antineoplastic systemic therapy end, or death relative to the rwP event) ranged from 59% (aMel) to 72% (mBC). Median rwPFS ranged from 3.7 (aMel) to 7.7 (mBC) months, and median rwTTP ranged from 4.6 (aMel) to 8.3 (mRCC) months. Correlations between rwOS and rwPFS ranged from 0.52 (aMel) to 0.82 (SCLC). The correlation between rwOS and rwTTD was often lower relative to other comparisons (range 0.40-0.62).

CONCLUSION

Derivation of a rwP variable from EHR documentation is feasible and reliable across the five solid tumors. Endpoint analyses show that rwP produces clinically meaningful information.

Evidence-based Urology: Surrogate Endpoints - For

The use of intermediate clinical endpoints and overall survival surrogates can shorten trial duration and related costs. This would potentially allow for an earlier introduction in practice of novel practice changing medications or treatments with a consequent impact on patient prognosis.

Conditional copula models for correlated survival endpoints: Individual patient data meta-analysis of randomized controlled trials

Correlations among survival endpoints are important for exploring surrogate endpoints of the true endpoint. With a valid surrogate endpoint tightly correlated with the true endpoint, the efficacy of a new drug/treatment can be measurable on it. However, the existing methods for measuring correlation between two endpoints impose an invalid assumption: correlation structure is constant across different treatment arms. In this article, we reconsider the definition of Kendall's concordance measure (tau) in the context of individual patient data meta-analyses of randomized controlled trials. According to our new definition of Kendall's tau, its value depends on the treatment arms. We then suggest extending the existing copula (and frailty) models so that their Kendall's tau can vary across treatment arms. Our newly proposed model, a joint frailty-conditional copula model, is the implementation of the new definition of Kendall's tau in meta-analyses. In order to facilitate our approach, we develop an original R function condCox.reg(.) and make it available in the R package joint.Cox (https://CRAN.R-project.org/package=joint.Cox). We apply the proposed method to a gastric cancer dataset (3288 patients in 14 randomized trials from the GASTRIC group). This data analysis concludes that Kendall's tau has different values between the surgical treatment arm and the adjuvant chemotherapy arm (p-value<0.001), whereas disease-free survival remains a valid surrogate at individual level for overall survival in these trials.

Concordance index: Surrogacy of progression-free survival for overall survival

In oncology clinical trials, the primary endpoint is often time to an event of clinical interest, e.g., time to disease progression or time to death. As a result, progression-free survival (PFS: the time from initiation of treatment till disease progression or death whichever occurs first) and overall survival (OS: the time from initiation of treatment till death) are the focus of statistical analysis in comparison of two treatment arms. It is often argued that PFS may serve as a surrogate endpoint for OS, while the validity of such surrogacy is still under debates in different types of cancer. In practice, one may observe a significant difference in PFS but no significant difference in OS; or vice versa. We provide a concordance index (C-index) to measure the degree of concordance between PFS and OS, and elaborate on the PFS vs OS discrepancies using the C-index using simulation studies and real trial analysis.

Prolonged progression-free survival and overall survival are associated with diabetes mellitus but inversely associated with levels of blood glucose in patients with lung cancer

BACKGROUND

Previous studies have provided conflicting evidence about the increased overall survival (OS) in lung cancer patients with diabetes mellitus (DM) compared with those without DM. This study assessed progression-free survival (PFS)/OS in lung cancer patients with or without DM and tentatively analyzed the impact of blood glucose levels on PFS/OS in lung cancer patients.

METHODS

Data were collected from lung cancer patients based upon admission records from January 2010 to January 2012 and follow-up records from January 2010 to January 2015 in the Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai. The data included patient sex, age, body mass index (BMI), smoking status, history of DM, level of blood glucose, pathological type, clinical stage of cancer, chemotherapy regimen, and history of anti-DM drugs. The Cox regression model and Kaplan-Meier method were used for the analysis of hazard factors and PFS/OS. For comparison of PFS/OS in lung cancer with or without DM, patients were divided into three groups: lung cancer with DM, lung cancer without DM but with elevated level of blood glucose, lung cancer without DM or elevated level of blood glucose.

RESULTS

In total, the data from 200 lung cancer patients (138 males/62 females, aged 29.0 to 78.0 years, mean 60.0 ± 8.6 years) were collected. For the comparison of PFS/OS in lung cancer patients with or without DM, patients were divided into three groups: lung cancer with DM (n = 31); lung cancer without DM but with elevated levels of blood glucose (n = 40); and lung cancer without both DM and elevated levels of blood glucose (n = 128), whereas 1 patient dropped out of the study. All the patients underwent complete chemotherapy and were followed up for 36.0 to 60.0 months. Kaplan-Meier survival analysis showed that lung cancer patients with DM had increased PFS and OS compared with those without DM (log-rank, P < 0.05, P < 0.01); the median PFS in lung cancer with DM was 12.0 months (95% confidence interval [CI], 4.0-16.0) vs. 6.0 months in those without DM (95% CI, 5.8-6.3); and the median OS in lung cancer patients with DM was 37.0 months (95% CI, 29.0-46.6) vs. 12.0 months in those without DM (95% CI, 10.9-13.1). For the other two groups of patients without DM, there was a trend toward a shorter PFS and OS in patients with elevated blood glucose compared with those without elevated blood glucose. Cox regression showed that PFS in lung cancer patients was favorably associated with the usage of anti-DM drugs, BMI, clinical stage of cancer, and chemotherapy regimen (all P < 0.05) but was inversely associated with the level of blood glucose (P < 0.05).

CONCLUSIONS

Lung cancer patients with DM have prolonged PFS and OS compared with those without DM, and the level of blood glucose was inversely associated with PFS. The current results indicate that PFS may be a meaningful intermediate endpoint for OS and that the levels of blood glucose hopefully represent a prognostic factor in lung cancer patients.

Metastasectomy and Targeted Therapy for Patients With Spinal Metastases of Renal Cell Carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is an aggressive malignant disease that frequently metastasizes to the spine. The main purpose of our study is to evaluate the influence of surgery as well as targeted therapy on the survival of patients with RCC metastases of the spine.

METHODS

Retrospective cohort study. We identified 100 patients with spinal RCC metastases who were retrospectively reviewed for preoperative conditions, treatment, and survival. Metastasectomy was performed in 39 cases, and 61 patients underwent decompression procedures with stabilization. Only 26 patients had adjuvant targeted therapy (7 with metastasectomy, 19 with palliative decompression). Pain, neurological status, survival time (from operation to death or last follow up), and local progression-free survival were evaluated.

RESULTS

Neurological function recovery and reported significant pain relief were observed. There was no significant difference in overall survival for the patients with metastasectomy and palliative decompression (P = .750). Metastasectomy provided better local control of disease compared with decompression (P = .043). There was a statistically significant difference in overall survival for the patients who received targeted therapy (P = .012).

CONCLUSIONS

Metastasectomy is effective for local control of tumors. Targeted therapy can potentially prolong overall survival for patients with spinal RCC metastases.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Our findings suggest that spinal metastasectomy is useful for local control of tumor growth but not for live expectancy. Effective systemic therapy is key role in stopping of disease progression.

CHALLENGES AND METHODOLOGIES IN USING PROGRESSION FREE SURVIVAL AS A SURROGATE FOR OVERALL SURVIVAL IN ONCOLOGY

OBJECTIVES

A primary outcome in oncology trials is overall survival (OS). However, to estimate OS accurately requires a sufficient number of patients to have died, which may take a long time. If an alternative end point is sufficiently highly correlated with OS, it can be used as a surrogate. Progression-free survival (PFS) is the surrogate most often used in oncology, but does not always satisfy the correlation conditions for surrogacy. We analyze the methodologies used when extrapolating from PFS to OS.

METHODS

Davis et al. previously reviewed the use of surrogate end points in oncology, using papers published between 2001 and 2011. We extend this, reviewing papers published between 2012 and 2016. We also examine the reporting of statistical methods to assess the strength of surrogacy.

RESULTS

The findings from 2012 to 2016 do not differ substantially from those of 2001 to 2011: the same factors are shown to affect the relationship between PFS and OS. The proportion of papers reporting individual patient data (IPD), strongly recommended for full assessment of surrogacy, remains low: 33 percent. A wide range of methods has been used to determine the appropriateness of surrogates. While usually adhering to reporting standards, the standard of scholarship appears sometimes to be questionable and the reporting of results often haphazard.

CONCLUSIONS

Standards of analysis and reporting PFS to OS surrogate studies should be improved by increasing the rigor of statistical reporting and by agreeing to a minimum set of reporting guidelines. Moreover, the use of IPD to assess surrogacy should increase.

Surrogate endpoints shortening the therapeutic evaluation duration for different subgroups of patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: A retrospective analysis of 830 patients stratified by the 8th edition of the UICC/AJCC staging system and plasma Epstein-Barr viral

Purpose: Investigating surrogate endpoints shortening the time of therapeutic evaluation in nasopharyngeal carcinoma (NPC) after radical treatment.

Patients and Methods: We retrospectively analyzed 830 patients receiving intensity-modulated radiotherapy (IMRT) from 2008 to 2010 and being stratified by the 8th edition of UICC/AJCC staging system and the plasma Epstein-Barr virus DNA (EBV DNA). The annual rates of overall survival (OS), progression-free survival (PFS), loco-regional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were sequentially calculated using the life table and compared by the McNemar method.

Results: The time of shortening therapeutic evaluation by surrogate endpoints: OS, PFS, LRFS and DMFS could be shortened to 1-year (100% vs 100%, P=1) in patients with stage I; OS, PFS, LRFS and DMFS could be shortened to 3-year (96.9% vs 96.1%, P = 1; 94.6% vs 92.2%, P = 0.125; 96.9% vs 95.3%, P = 0.5) and 4-year (92.2% vs 91.2%, P = 0.125) in stage II; In the high EBV DNA group , OS and DMFS could be shortened to 1-year (100% vs 100%, P = 1;100% vs 100%, P = 0.25) in stage II; OS and PFS could be shortened to 3-year (94.3% vs 91.4%, P = 1;82.9% vs 74.3%, P = 0.25) in stage III; OS could be shortened to 4-year (75% vs 72.7%, P = 1) in stage IVA.

Conclusions: The time of therapeutic evaluation could be shortened to <5-year in stages I-II patients. The year of surrogate endpoints could be ahead in stages II-IVA with high EBV DNA.

Progression-free survival as a surrogate endpoint of overall survival in patients with metastatic colorectal cancer

Background

In many clinical trials designed to assess the efficacy of anticancer treatments, overall survival (OS) is often used as a primary endpoint despite its several points of weakness.

Methods

This study evaluated the role of progression-free survival (PFS) in the first three lines of treatment as a potential surrogate endpoint of OS in patients with metastatic colorectal cancer (MCRC). One hundred and twenty patients with MCRC were enrolled in this study. The median PFS of the first-, second-, and third-lines of treatment and the OS were evaluated. The correlation between the time to progression and the OS was analyzed. The median PFS of the three lines of treatment were 8.5, 5, and 3 months, respectively.

Results

The median OS was 32.4 months. A modest correlation was found between the PFS to the first-line treatment with Folfox–avastin and OS. Similar data were obtained with the second-line treatment. However, no correlation was found between the PFS and OS during the third-line treatment. The regression analysis revealed that PFS is predictive of OS.

Conclusion

In brief, the PFS of the first- and second-lines of treatment could be a good candidate as a surrogate endpoint of OS in patients with MCRC.

Cabozantinib versus sunitinib as initial therapy for metastatic renal cell carcinoma of intermediate or poor risk (Alliance A031203 CABOSUN randomised trial): Progression-free survival by independent review and overall survival update

BACKGROUND

The randomised phase 2 CABOSUN trial comparing cabozantinib with sunitinib as initial therapy for advanced renal cell carcinoma (RCC) of intermediate or poor risk met the primary end-point of improving progression-free survival (PFS) as assessed by investigator. We report PFS by independent radiology review committee (IRC) assessment, ORR per IRC and updated overall survival (OS).

PATIENTS AND METHODS

Previously untreated patients with advanced RCC of intermediate or poor risk by IMDC criteria were randomised 1:1 to cabozantinib 60 mg daily or sunitinib 50 mg daily (4 weeks on/2 weeks off). Stratification was by risk group and presence of bone metastases.

RESULTS

A total of 157 patients were randomised 1:1 to cabozantinib (n = 79) or sunitinib (n = 78). Median PFS per IRC was 8.6 months (95% confidence interval [CI] 6.8-14.0) versus 5.3 months (95% CI 3.0-8.2) for cabozantinib versus sunitinib (hazard ratio [HR] 0.48 [95% CI 0.31-0.74]; two-sided p = 0.0008), and ORR per IRC was 20% (95% CI 12.0-30.8) versus 9% (95% CI 3.7-17.6), respectively. Subgroup analyses of PFS by stratification factors and MET tumour expression were consistent with results for the overall population. With a median follow-up of 34.5 months, median OS was 26.6 months (95% CI 14.6-not estimable) with cabozantinib and 21.2 months (95% CI 16.3-27.4) with sunitinib (HR 0.80 [95% CI 0.53-1.21]. The incidence of grade 3 or 4 adverse events was 68% for cabozantinib and 65% for sunitinib.

CONCLUSIONS

In this phase 2 trial, cabozantinib treatment significantly prolonged PFS per IRC compared with sunitinib as initial systemic therapy for advanced RCC of poor or intermediate risk.

TRIAL REGISTRATION NUMBER

NCT01835158.

Statistical controversies in clinical research: data access and sharing-can we be more transparent about clinical research? Let's do what's right for patients

Calls for greater transparency and 'open data access' in clinical research are widespread, from sources including the Executive Office of the President, which in 2013 called for increased access to the results of federally funded research. In 2015, The Institute of Medicine issued a report advocating for a multi-stakeholder effort to foster responsible data sharing, and there are many others. Open science is good for researchers, good for innovation, and good for patients. The question at the center of the open-science efforts for clinical trials should not be whether data should be shared, but rather how we can usher in responsible methods for doing so. Unfortunately, there remain numerous perceived barriers to complete transparency around clinical trial data. This paper reviews the current status of data disclosure, the barriers to achieving it and a suggestion for the future.

Strength of Validation for Surrogate End Points Used in the US Food and Drug Administration's Approval of Oncology Drugs

OBJECTIVE

To determine the strength of the surrogate-survival correlation for cancer drug approvals based on a surrogate.

PARTICIPANTS AND METHODS

We performed a retrospective study of the US Food and Drug Administration (FDA) database, with focused searches of MEDLINE and Google Scholar. Among cancer drugs approved based on a surrogate end point, we examined previous publications assessing the strength of the surrogate-survival correlation. Specifically, we identified the percentage of surrogate approvals lacking any formal analysis of the strength of the surrogate-survival correlation, and when conducted, the strength of such correlations.

RESULTS

Between January 1, 2009, and December 31, 2014, the FDA approved marketing applications for 55 indications based on a surrogate, of which 25 were accelerated approvals and 30 were traditional approvals. We could not find any formal analyses of the strength of the surrogate-survival correlation in 14 out of 25 accelerated approvals (56%) and 11 out of 30 traditional approvals (37%). For accelerated approvals, just 4 approvals (16%) were made where a level 1 analysis (the most robust way to validate a surrogate) had been performed, with all 4 studies reporting low correlation (r≤0.7). For traditional approvals, a level 1 analysis had been performed for 15 approvals (50%): 8 (53%) reported low correlation (r≤0.7), 4 (27%) medium correlation (r>0.7 to r<0.85), and 3 (20%) high correlation (r≥0.85) with survival.

CONCLUSIONS

The use of surrogate end points for drug approval often lacks formal empirical verification of the strength of the surrogate-survival association.

First-line treatment in the management of advanced renal cell carcinoma: systematic review and network meta-analysis

OBJECTIVES

To conduct a systematic review and network meta-analysis (NMA) to assess effectiveness of first-line treatments for advanced renal cell carcinoma (RCC).

METHODS

Database searches were conducted to identify randomized controlled trials (RCTs) reporting results for eligible treatments. A fixed-effect Bayesian NMA was conducted to assess the relative effectiveness of treatments, with progression-free survival (PFS) reported as hazard ratios (HRs) and 95% credible intervals (CrIs).

RESULTS

Eleven unique RCTs were suitable for inclusion in the NMA. In the base case, in terms of PFS, sunitinib was superior compared with bevacizumab + IFN-α (HR = 0.79, 95% CrI: 0.64 - 0.96), everolimus (HR = 0.70, 95% CrI: 0.56 - 0.87), sorafenib (HR = 0.56, 95% CrI: 0.40 - 0.77) and temsirolimus + bevacizumab (HR = 0.74, 95% CrI: 0.56 - 0.96). Although, the point values for the mean and median HRs were < 1.0, there was no significant difference in PFS between sunitinib and axitinib, pazopanib or tivozanib. Although sensitivity analyses impacted the results of the NMA, no treatment was significantly more efficacious than sunitinib.

CONCLUSION

Results from this analysis suggest that there is no treatment superior to the current benchmark treatment, sunitinib, in the management of advanced RCC in the first-line setting.

Bevacizumab: a review of its use in advanced cancer

The humanized monoclonal antibody bevacizumab (Avastin(®)) has been available in the EU since 2005. Results of phase III trials demonstrate that adding intravenous bevacizumab to antineoplastic agents improves progression-free survival and/or overall survival in patients with advanced cancer, including when used as first- or second-line therapy in metastatic colorectal cancer, as first-line therapy in advanced nonsquamous non-small cell lung cancer, as first-line therapy in metastatic renal cell carcinoma, as first-line therapy in metastatic breast cancer, and as first-line therapy in epithelial ovarian, fallopian tube or primary peritoneal cancer or in recurrent, platinum-sensitive or platinum-resistant disease. Results of these studies are supported by the findings of routine oncology practice studies conducted in real-world settings. The tolerability profile of bevacizumab is well defined and adverse events associated with its use (e.g. hypertension, proteinuria, haemorrhage, wound healing complications, arterial thromboembolism, gastrointestinal perforation) are generally manageable. In conclusion, bevacizumab remains an important option for use in patients with advanced cancer.

Detecting overall survival benefit derived from survival postprogression rather than progression-free survival

Broglio and Berry (2009) examined the impact of survival postprogression (SPP) on overall survival (OS) when progression-free survival (PFS) was used to assess treatment effect in metastatic cancer. Their simulation studies found no statistical difference in OS because of dilution effect from SPP, although there was a statistical difference in PFS between treatment arms. Recently, two phase III clinical trials showed efficacy of experimental treatments in OS, but not PFS. These results seem counterintuitive, because it may be reasonable to consider that the effect of treatment in prolonging PFS can influence OS prolongation. We conducted simulations to examine the role of SPP in OS under the assumption that only SPP, and not PFS, differed between treatment arms. We also explored the impact of patient heterogeneity on the OS analysis. Our study offers a reasonable explanation for the two phase III trials and recommends further discussion of PFS as an adequate endpoint and what role SPP might play in OS to evaluate current treatment regimens.

A novel test to compare two treatments based on endpoints involving both nonfatal and fatal events

In a clinical trial comparing two treatment groups, one commonly-used endpoint is time to death. Another is time until the first nonfatal event (if there is one) or until death (if not). Both endpoints have drawbacks. The wrong choice may adversely affect the value of the study by impairing power if deaths are too few (with the first endpoint) or by lessening the role of mortality if not (with the second endpoint). We propose a compromise that provides a simple test based on the time to death if the patient has died or time since randomization augmented by an increment otherwise. The test applies the ordinary two-sample Wilcoxon statistic to these values. The formula for the increment (the same for experimental and control patients) must be specified before the trial starts. In the simplest (and perhaps most useful) case, the increment assumes only two values, according to whether or not the (surviving) patient had a nonfatal event. More generally, the increment depends on the time of the first nonfatal event, if any, and the time since randomization. The test has correct Type I error even though it does not handle censoring in a customary way. For conditions where investigators would face no easy (advance) choice between the two older tests, simulation results favor the new test. An example using a renal-cancer trial is presented.

Acceptance of surrogate end points in clinical trials supporting approval of drugs for cancer treatment by the Japanese regulatory agency

BACKGROUND

This study investigated the historic use of different end points to support approval of drugs for cancer treatment in Japan.

PATIENTS AND METHODS

Anticancer drugs approved between April 2001 and April 2014 were comprehensively investigated using publicly available information.

RESULTS

Before the revision of the guideline for oncology drugs in April 2006 in Japan, >80% of end points supporting approval were response rate and overall survival (OS) was not frequent. After the revision of the guideline in Japan, using OS in pivotal clinical trials applied for approval increased to more than approximately one-third of oncology drugs, although trials with an end point of response rate decreased. Regarding drugs for major cancers including non-small-cell lung cancer, gastric cancer, colorectal cancer, and breast cancer, survival was used as an end point in 44.0%, whereas surrogate end points were used in 56.0%. Exploration of potential factors for using surrogate end points other than survival carried out through determinations of odds ratios and 95% confidence intervals identified 'orphan drug designation in Japan' and 'accelerated approval by the U.S. Food and Drug Administration' as significant factors.

CONCLUSIONS

The revised guideline for oncology drugs in Japan requires the results of phase 3 studies with survival as an end point at the time of new drug application at least for major cancers. The regulatory agency in Japan also accepts surrogate end points as end points supporting approval besides survival; however, the number of surrogate end points has decreased after the revision of the guideline. We consider that accepting surrogate end points in the Japanese regulatory systems is important to approve oncology drugs quickly in Japan.

Resampling the N9741 trial to compare tumor dynamic versus conventional end points in randomized phase II trials

PURPOSE

The optimal end point for randomized phase II trials of anticancer therapies remains controversial. We simulated phase II trials by resampling patients from N9741, a randomized phase III trial of chemotherapy regimens for metastatic colorectal cancer, and compared the power of various end points to detect the superior therapy (FOLFOX [infusional fluorouracil, leucovorin, and oxaliplatin] had longer overall survival than both IROX [irinotecan plus oxaliplatin] and IFL [irinotecan and bolus fluorouracil plus leucovorin]).

METHODS

Tumor measurements and progression-free survival (PFS) data were obtained for 1,471 patients; 1,002 had consistently measured tumors and were resampled (5,000 replicates) to simulate two-arm, randomized phase II trials with α = 0.10 (one sided) and 20 to 80 patients per arm. End points included log ratio of tumor size at 6, 12, and 18 weeks relative to baseline; time to tumor growth (TTG), estimated using a nonlinear mixed-effects model; and PFS. Arms were compared using rank sum tests for log ratio and TTG and a log-rank test for PFS.

RESULTS

For FOLFOX versus IFL, TTG and PFS had similar power, with both exceeding the power of log ratio at 18 weeks; for FOLFOX versus IROX, TTG and log ratio at 18 weeks had similar power, with both exceeding the power of PFS. The best end points exhibited > 80% power with 60 to 80 patients per arm.

CONCLUSION

TTG is a powerful end point for randomized phase II trials of cytotoxic therapies in metastatic colorectal cancer; it was either comparable or superior to PFS and log ratio at 18 weeks. Additional studies will be needed to clarify the potential of TTG as a phase II end point.

Evaluating surrogacy metrics and investigating approval decisions of progression-free survival (PFS) in metastatic renal cell cancer: a systematic review

BACKGROUND

In metastatic renal cell cancer (mRCC) trials, progression-free survival (PFS) is increasingly used instead of overall survival (OS) as the approval end point. Unlike other solid tumors, there is no published demonstration of what PFS is needed across and by treatment class in mRCC. We determine this and evaluate drug approval decisions in mRCC targeted therapy.

METHODS

We identified all randomized, controlled trials reporting PFS and OS in mRCC. Surrogacy metrics were the coefficient of determination and surrogate threshold effect (STE)-the PFS difference needed to predict, with 95% confidence, an OS difference. Data from regulatory commentaries, briefing documents and transcripts were extracted.

RESULTS

No exclusively chemotherapy trial met criteria. Of 30 qualifying trials, 11 trials (13 comparisons) used targeted therapy. The all-trials and immunotherapy-only trials analysis failed to demonstrate a STE. The targeted trials, using the more conservative regression analysis demonstrated an STE of 3.9 months and an R(2) of 0.44. Crossover upon progression, control to active treatment, was common. Regulatory approval, accelerated or regular, labeling, interim analyses, and adjudication were context specific.

CONCLUSIONS

A new targeted therapy trial showing a PFS difference of 3.9 months can claim an OS benefit in mRCC. PFS surrogacy for OS in metastatic renal cell is not generalizable across all drug classes.