Progression-free survival as a surrogate for overall survival in first-line chemotherapy for advanced pancreatic cancer

Short-term serial circulating tumor DNA assessment predicts therapeutic efficacy for patients with advanced pancreatic cancer

PURPOSE

We investigated the potential clinical utility of short-term serial KRAS-mutated circulating cell-free tumor DNA (ctDNA) assessment for predicting therapeutic response in patients undergoing first-line chemotherapy for advanced pancreatic cancer.

METHODS

We collected 144 blood samples from 18 patients with locally advanced or metastatic cancer that were undergoing initial first-line chemotherapy of gemcitabine plus nab-paclitaxel (GEM plus nab-PTX). Analysis of KRAS-mutated ctDNA was quantified by digital droplet polymerase chain reaction (ddPCR) as mutant allele frequency (MAF). This study investigated pretreatment KRAS-mutated ctDNA status and ctDNA kinetics every few days (days 1, 3, 5 and 7) after initiation of chemotherapy and their potential as predictive indicators.

RESULTS

Of the 18 enrolled patients, an increase in KRAS-mutated ctDNA MAF values from day 0-7 after initiation of chemotherapy was significantly associated with disease progression (P < 0.001). Meanwhile, positive pretreatment ctDNA status (MAF ≥ 0.02%) (P = 0.585) and carbohydrate antigen 19-9 (CA19-9) values above the median (P = 0.266) were not associated with disease progression. In univariate analysis, this short-term increase in ctDNA MAF values (day 0-7) was found to be associated with significantly shorter progression free survival (PFS) (hazard ration [HR], 24.234; range, (2.761-212.686); P = 0.0002).

CONCLUSION

This short-term ctDNA kinetics assessment may provide predictive information to reflect real-time therapeutic response and lead to effective refinement of regimen in patients with advanced pancreatic cancer undergoing systemic chemotherapy.

Association Between Intermediate End Points, Progression-free Survival, and Overall Survival in First-line Advanced or Recurrent Endometrial Cancer

PURPOSE

Advanced/recurrent endometrial cancer is associated with poor long-term outcomes. Clinical studies of novel regimens are ongoing, but given that data on overall survival (OS) take a long time to mature, surrogate end points are often used to support clinical-research interpretation. The aim of this study was to explore the correlation between progression-free survival (PFS)/time to progression (TTP) and OS across multiple time points in the first-line treatment of advanced/recurrent endometrial cancer.

METHODS

This study comprised meta-analyses of Phase 2/3 randomized, controlled trials of first-line treatments in patients with advanced primary or first-recurrent endometrial cancer identified via systematic literature review. The strength of the surrogacy relationship was assessed by correlation analyses (estimated with Spearman and Pearson correlation coefficients) and weighted linear regression.

FINDINGS

Data from 15 studies were included. PFS and TTP (TTP was reported in one study only) were highly correlated with future OS at multiple time points (Spearman values, 0.83-0.90; Pearson values, 0.86-0.93), suggesting that a change in PFS/TTP would likely be correlated with a change in OS in the same direction. On weighted linear regression, a 10% increase in PFS/TTP probability was significantly associated with a 9.3% to 13.3% increase in the probability of future OS. The strong positive association between PFS/TTP and OS was supported by findings from sensitivity analyses based on identified sources of interstudy heterogeneity.

IMPLICATIONS

PFS/TTP is a good potential candidate for predicting long-term OS outcomes in trials of first-line treatment in patients with advanced/recurrent endometrial cancer. The findings from this report may help to inform health-authority and clinical decision makers that PFS/TTP improvements are likely to translate into subsequent OS improvements once data mature.

Tislelizumab plus chemotherapy versus pembrolizumab plus chemotherapy for the first-line treatment of advanced non-small cell lung cancer: systematic review and indirect comparison of randomized trials

Purpose: Pembrolizumab and tislelizumab have demonstrated significant clinical benefits in first-line treatment for advanced NSCLC. However, no head-to-head clinical trial has ever compared the optimal choice. Therefore, we conducted an indirect comparison to explore the optimal choice for advanced NSCLC combined with chemotherapy. Methods: We conducted a systematic review of randomized trials; the clinical outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs). Indirect comparisons between tislelizumab and pembrolizumab were conducted with the Bucher method. Results: Data were abstracted from 6 randomized trials involving more than 2,000 participants. Direct meta-analysis showed that both treatment regimens improved clinical outcomes compared with chemotherapy alone (PFS: hazard ratio (HR)_{tis+chemo/chemo} 0.55, 95% CI 0.45-0.67; HR_{pem+chemo/chemo} 0.53, 95% CI 0.47-0.60; ORR: relative risk (RR)_{tis+chemo/chemo} 1.50, 95% CI 1.32-1.71; RR_{pem+chemo/chemo} 1.89, 95% CI 1.44-2.48). Regarding safety outcomes, tislelizumab and pembrolizumab have a higher risk in the incidence of grade 3 or higher AEs (RR_{tis+chemo/chemo} 1.12, 95% CI 1.03-1.21; RR_{pem+chemo/chemo} 1.13, 95% CI 1.03-1.24). The indirect comparison showed that there was no significant difference between tislelizumab plus chemotherapy and pembrolizumab plus chemotherapy in terms of PFS (HR: 1.04, 95% CI 0.82-1.31), ORR (RR: 0.79, 95% CI 0.59-1.07), the incidence of grade 3 or higher AEs (RR 0.99, 95% CI 0.87-1.12), and AEs leading to death (RR 0.70, 95% CI 0.23-2.09). In progression-free survival subgroup analysis, the results demonstrate no significant differences in PFS by PD-L1 TPS expression level, age, liver metastasis status, and smoking status between tislelizumab plus chemotherapy and pembrolizumab plus chemotherapy. Conclusion: The efficacy and safety of tislelizumab combination chemotherapy were not substantially different from pembrolizumab combination chemotherapy.

Copula graphic estimation of the survival function with dependent censoring and its application to analysis of pancreatic cancer clinical trial

In this article, we consider a survival function estimation method that may be suitable for analyses of clinical trials of cancer treatments whose prognosis is known to be poor such as pancreatic cancer treatment. Typically, these kinds of trials are not double-blind, and patients in the control group may drop out in more significant numbers than in the treatment group if their disease progresses (DP). If disease progression is associated with a higher risk of death, then censoring becomes dependent. To estimate the survival function with dependent censoring, we use copula-graphic estimation, where a parametric copula function is used to model the dependence in the joint survival function of the event and censoring time. In this article, we propose a novel method that one can use in choosing the copula parameter. As an application example, we estimate the survival function of the overall survival time of the KG4/2015 study, the phase 3 clinical trial of the efficacy of GV1001 as a treatment for pancreatic cancer. We provide both statistical and clinical pieces of evidence that support the violation of independent censoring. Applying the estimation method with dependent censoring, we obtain that the estimates of the median survival times are 339 days in the treatment group and 225.5 days in the control group. We also find that the estimated difference of the medians is 113.5 days, and the difference is statistically significant at the one-sided level with size 2.5%.

Staging CT and Diagnostic Laparoscopy With Cytology Prior to the Treatment of Pancreatic Adenocarcinoma: A Case Series

INTRODUCTION

Initial staging of pancreatic ductal adenocarcinoma (PDAC) is performed with computed tomography (CT). Laparoscopy with peritoneal cytology at staging can uncover occult disease undetected by CT. This case series assessed clinical course following staging laparoscopy with cytology in patients with PDAC.

METHODS

This single-center study examined patients with non-metastatic PDAC diagnosed from 2017 to 2020. Patients underwent CT and subsequent laparoscopy with cytology prior to treatment. Demographics, clinicopathologic status, treatment course, and survival were compared.

RESULTS

Eight patients were identified. All had negative laparoscopies. Five cytologies were negative, two were atypical, and one was positive. Two patients with negative cytology received neoadjuvant chemotherapy and underwent resection, with an average follow-up time of 32.9 months since diagnosis. Of the three remaining patients with negative cytology, none underwent resection. One received delayed chemotherapy, while the others could not due to medical contraindications. The average survival was 3.5 months (n=2). Of two patients with atypical cytology, neither underwent resection. One could not receive chemotherapy due to medical contraindication, while the other was lost to follow-up shortly after diagnosis. The average survival was 1.3 months (n=1). The patient with positive cytology received definitive chemotherapy without resection and survived for 21.6 months.

CONCLUSIONS

The patient with positive cytology may have been spared non-therapeutic surgery. Remaining unresected patients showed poor survival, though the lack of immediate chemotherapy may contribute to this finding. Further research is needed to determine optimal candidates for invasive staging and implications of atypical cytology.

Modelling approaches for histology-independent cancer drugs to inform NICE appraisals: a systematic review and decision-framework

BACKGROUND

The first histology-independent marketing authorisation in Europe was granted in 2019. This was the first time that a cancer treatment was approved based on a common biomarker rather than the location in the body at which the tumour originated. This research aims to explore the implications for National Institute for Health and Care Excellence appraisals.

METHODS

Targeted reviews were undertaken to determine the type of evidence that is likely to be available at the point of marketing authorisation and the analyses required to support National Institute for Health and Care Excellence appraisals. Several challenges were identified concerning the design and conduct of trials for histology-independent products, the greater levels of heterogeneity within the licensed population and the use of surrogate end points. We identified approaches to address these challenges by reviewing key statistical literature that focuses on the design and analysis of histology-independent trials and by undertaking a systematic review to evaluate the use of response end points as surrogate outcomes for survival end points. We developed a decision framework to help to inform approval and research policies for histology-independent products. The framework explored the uncertainties and risks associated with different approval policies, including the role of further data collection, pricing schemes and stratified decision-making.

RESULTS

We found that the potential for heterogeneity in treatment effects, across tumour types or other characteristics, is likely to be a central issue for National Institute for Health and Care Excellence appraisals. Bayesian hierarchical methods may serve as a useful vehicle to assess the level of heterogeneity across tumours and to estimate the pooled treatment effects for each tumour, which can inform whether or not the assumption of homogeneity is reasonable. Our review suggests that response end points may not be reliable surrogates for survival end points. However, a surrogate-based modelling approach, which captures all relevant uncertainty, may be preferable to the use of immature survival data. Several additional sources of heterogeneity were identified as presenting potential challenges to National Institute for Health and Care Excellence appraisal, including the cost of testing, baseline risk, quality of life and routine management costs. We concluded that a range of alternative approaches will be required to address different sources of heterogeneity to support National Institute for Health and Care Excellence appraisals. An exemplar case study was developed to illustrate the nature of the assessments that may be required.

CONCLUSIONS

Adequately designed and analysed basket studies that assess the homogeneity of outcomes and allow borrowing of information across baskets, where appropriate, are recommended. Where there is evidence of heterogeneity in treatment effects and estimates of cost-effectiveness, consideration should be given to optimised recommendations. Routine presentation of the scale of the consequences of heterogeneity and decision uncertainty may provide an important additional approach to the assessments specified in the current National Institute for Health and Care Excellence methods guide.

FURTHER RESEARCH

Further exploration of Bayesian hierarchical methods could help to inform decision-makers on whether or not there is sufficient evidence of homogeneity to support pooled analyses. Further research is also required to determine the appropriate basis for apportioning genomic testing costs where there are multiple targets and to address the challenges of uncontrolled Phase II studies, including the role and use of surrogate end points.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 76. See the NIHR Journals Library website for further project information.

Surrogate Endpoints in Oncology: Overview of Systematic Reviews and Their Use for Health Decision Making in Mexico

OBJECTIVES

The use of surrogate endpoints (SEs) for cancer drug approval in health systems is common. The objectives of this study were to identify systematic reviews (SRs) that evaluated the correlation of SEs with overall survival (OS) in cancer drugs to analyze the applications of approved cancer drugs with SEs in Mexico and to apply the validation framework proposed by the Institute for Quality and Efficiency in Health Care (IQWiG).

METHODS

An overview of SRs was conducted according to Cochrane Collaboration methodology. Applications for approved cancer drugs with SEs in Mexico were analyzed. The IQWiG validation framework was applied to evaluate the SEs identified in the overview and in the applications in Mexico.

RESULTS

A total of 85 SRs that assessed 192 SEs for different types of cancer were selected. According to the IQWiG model, only 2.5% of the SEs analyzed in the overview and only one of the applications in Mexico could be used as surrogates for OS because the reliability (methodological quality) of the SRs and the strength of the correlation of SEs with OS was mostly low (92%) and low (correlation coefficient r ≤ 0.7; 50.5%), respectively. Of the total number of cancer drugs approved in Mexico, 19.4% used SEs.

CONCLUSIONS

Most SEs for different types of cancer could not be used as surrogates for OS according to the IQWiG model, and their use for the approval of cancer drugs in Mexico is generally not justified.

A systematic review of meta-analyses assessing the validity of tumour response endpoints as surrogates for progression-free or overall survival in cancer

BACKGROUND

Tumour response endpoints, such as overall response rate (ORR) and complete response (CR), are increasingly used in cancer trials. However, the validity of response-based surrogates is unclear. This systematic review summarises meta-analyses assessing the association between response-based outcomes and overall survival (OS), progression-free survival (PFS) or time-to-progression (TTP).

METHODS

Five databases were searched to March 2019. Meta-analyses reporting correlation or regression between response-based outcomes and OS, PFS or TTP were summarised.

RESULTS

The systematic review included 63 studies across 20 cancer types, most commonly non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and breast cancer. The strength of association between ORR or CR and either PFS or OS varied widely between and within studies, with no clear pattern by cancer type. The association between ORR and OS appeared weaker and more variable than that between ORR and PFS, both for associations between absolute endpoints and associations between treatment effects.

CONCLUSIONS

This systematic review suggests that response-based endpoints, such as ORR and CR, may not be reliable surrogates for PFS or OS. Where it is necessary to use tumour response to predict treatment effects on survival outcomes, it is important to fully reflect all statistical uncertainty in the surrogate relationship.

The AST/ALT (De Ritis) ratio predicts clinical outcome in patients with pancreatic cancer treated with first-line nab-paclitaxel and gemcitabine: post hoc analysis of an Austrian multicenter, noninterventional study

Background:

The pretreatment De Ritis ratio [aspartate transaminase (AST)/alanine transaminase (ALT)] has been shown to be an adverse prognostic marker in various cancer entities. However, its relevance to advanced pancreatic ductal adenocarcinoma (PDAC) has not yet been studied. In the present study we investigated the AST/ALT ratio as a possible predictor of treatment response and disease outcome in patients with advanced PDAC treated with first-line gemcitabine/nab-paclitaxel.

Methods:

A post hoc analysis of a prospective, multicenter, noninterventional study was performed. A total of 202 patients with advanced PDAC treated with first-line gemcitabine/nab-paclitaxel for whom the AST/ALT ratio was measured were included in this analysis.

Results:

Median and 1-year progression-free survival estimates were 4.8 months and 5.1%, respectively in patients with an AST/ALT ratio above the 75th percentile of its distribution, and 6.0 months and 18.7%, respectively in patients with an AST/ALT ratio less than or equal to this cutoff, respectively (log-rank p = 0.004). In univariable Cox regression, a doubling of the AST/ALT ratio was associated with a 1.4-fold higher relative risk of progression or death [hazard ratio = 1.38, 95% confidence interval (CI): 1.06–1.80, p = 0.017]. The prognostic association was also found in multivariable analysis adjusting for Eastern Cooperative Oncology Group performance status and lung metastases (hazard ratio per AST/ALT ratio doubling = 1.32, 95% CI: 1.00–1.75, p = 0.047). In treatment response analysis, a doubling of the AST/ALT ratio was associated with a 0.5-fold lower odds of objective response (odds ratio = 0.54, 95% CI: 0.31–0.94, p = 0.020).

Conclusions:

The pretreatment serum AST/ALT ratio predicts poor disease outcome and response rate in patients with advanced PDAC treated with gemcitabine/nab-paclitaxel and might represent a novel and inexpensive marker for individual risk assessment in the treatment of pancreatic cancer.

A novel, more reliable approach to use of progression-free survival as a predictor of gain in overall survival: The Ottawa PFS Predictive Model

Progression-free survival (PFS) hazard ratios and gain in median PFS are suggested predictors of overall survival (OS) gain (with gain defined as experimental arm minus control arm values). We assessed use of half-lives (time to progression/death of half remaining patients). We reviewed randomized trials from Journal of Clinical Oncology and New England Journal of Medicine, 01/2012-06/12/2017 (discovery series) and 01/01/2007-12/31/2011 (first validation series). If PFS or OS gains were significant, we used PFS/OS curve nonlinear regression analysis to estimate half-lives and defined "half-life gain" as experimental minus control arm half-life. With low crossover and significant PFS differences, PFS half-life gains ≥1.5 months had positive-predictive-values for OS gains ≥2 months of 79 % and 86 % and PFS half-life gains <1.5 months had negative-predictive-values for OS gains <2 months of 95 % and 75 %, in discovery and validation series, respectively. PFS half-life gains more reliably predicted OS gains than PFS hazard ratios or gains in median PFS. Findings were confirmed in a second validation series.

Predictive Value of 99MTC-hynic-toc Scintigraphy in Lung Neuroendocrine Tumor Diagnosis

Background:

Νeuroendocrine tumors of the lungs are rare arising in the thymus and gastro-entero-pancreatic tract and belonging to foregut of neuroendocrine tumors. The aim of the present prospective study was to estimate the potential impact of single-photon emission computed tomography somatostatin receptor scintigraphy using 99mTc-Tektrotyd on diagnosis, treatment response, and prognosis in patients with neuroendocrine tumors of the lungs.

Methods:

Thirty-six patients with neuroendocrine tumors of the lungs were evaluated by using 99mTc-HYNIC-TOC scintigraphy. The scintigraphic results were compared to liver tissue uptake (Krenning score). Likewise, the functional imaging results were compared with biochemical indices including chromogranin A, neuroendocrine-specific enolase, and insulin-like growth factor 1 at the time of diagnosis (baseline) and disease progression.

Results:

The number of somatostatin receptors, expressed with Krenning score, did not show any correlation with the survival of patients both at baseline (P = .08) and at disease progression (P = .24), and scintigraphy results did not relate significantly to progression-free survival. Comparing the results of 99mTc-HYNIC-TOC scintigraphy according to the response of patients in the initial treatment, a statistically significant negative correlation was observed both in the first and in the second scintigraphy with patients’ response (P = .001 and P < .001, respectively). The concentrations of biochemical markers were in accordance with scintigraphy results in the diagnosis.

Conclusion:

This study indicates that 99mTc-HYNIC-TOC scintigraphy appears to be a reliable, noninvasive technique for detection of primary neuroendocrine tumors and their locoregional or distant metastases, although it cannot be used as a neuroendocrine tumors of the lungs predictive technique.

Evaluation of Phase II Trial Design in Advanced Pancreatic Cancer

OBJECTIVES

We evaluated how well phase II trials in locally advanced and metastatic pancreatic cancer (LAMPC) meet current recommendations for trial design.

METHODS

We conducted a systematic review of phase II first-line treatment trial for LAMPC. We assessed baseline characteristics, type of comparison, and primary end point to examine adherence to the National Cancer Institute recommendations for trial design.

RESULTS

We identified 148 studies (180 treatment arms, 7505 participants). Forty-seven (32%) studies adhered to none of the 5 evaluated National Cancer Institute recommendations, 62 (42%) followed 1, 31 (21%) followed 2, and 8 (5%) followed 3 recommendations. Studies varied with respect to the proportion of patients with good performance status (range, 0%-80%) and locally advanced disease (range, 14%-100%). Eighty-two (55%) studies concluded that investigational agents should progress to phase III testing; of these, 24 (16%) had documented phase III trials. Three (8%) phase III trials demonstrated clinically meaningful improvements for investigational agents. One of 38 phase II trials that investigated biological investigational agents was enriched for a biomarker.

CONCLUSIONS

Phase II trials do not conform well to current recommendations for trial design in LAMPC.

Evaluation of time to failure of strategy as an alternative surrogate endpoint in patients with lung cancer with EGFR mutations

Background

Epidermal growth factor receptor (EGFR) is one of the most common oncogenes in non-small cell lung cancer (NSCLC). EGFR-tyrosine kinase inhibitor (TKI) and platinum-doublet chemotherapy (PT) are effective regimens in patients with NSCLC harbouring EGFR mutations. Among these patients, progression-free survival (PFS) has been used as a surrogate endpoint; however, it may not correlate with overall survival (OS) due to crossover. Time to failure of strategy (TFS) has been proposed as an alternative endpoint in advanced colorectal cancer clinical trials where multiple effective therapies are provided either in combination or sequentially. Nevertheless, it remains unclear whether TFS is useful in lung cancer trials.

Patients and methods

We retrospectively reviewed patients with NSCLC harbouring EGFR mutations who chose a treatment strategy consisting of EGFR-TKI and PT as the initial two regimens at the National Cancer Center Hospital. We evaluated the relationship between PFS and OS and between TFS and OS.

Results

Between May 2005 and April 2015, a total of 374 patients were diagnosed with NSCLC harbouring EGFR mutations. Among them, 158 patients were eligible for analysis. The median PFS, TFS and OS of the patients were 11.2 months (95% CI 9.9 to 12.6), 21.3 months (95%  CI 18.6 to 26.2) and 36.6 months (95%  CI 32.0 to 41.8), respectively. OS and TFS, but not PFS, were better in patients who received PT then EGFR-TKI compared with those who received the opposite schedule. The non-parametric Spearman's rank correlation coefficients (r) between PFS and OS and between TFS and OS were 0.54 and 0.85, respectively.

Conclusions

This is the first report describing TFS data among patients with NSCLC with EGFR mutations who received EGFR-TKI and PT as the initial two regimens. TFS was acceptable as a surrogate endpoint for OS. Further validation in clinical trials is needed.