Time to progression as a surrogate marker for overall survival in patients with advanced non-small cell lung cancer

Patient eligibility for trials with imaging response assessment at the time of molecular tumor board presentation

PURPOSE

To assess the eligibility of patients with advanced or recurrent solid malignancies presented to a molecular tumor board (MTB) at a large precision oncology center for inclusion in trials with the endpoints objective response rate (ORR) or duration of response (DOR) based on Response Evaluation Criteria in Solid Tumors (RECIST version 1.1).

METHODS

Prospective patients with available imaging at the time of presentation in the MTB were included. Imaging data was reviewed for objectifiable measurable disease (MD) according to RECIST v1.1. Additionally, we evaluated the patients with MD for representativeness of the identified measurable lesion(s) in relation to the overall tumor burden.

RESULTS

262 patients with different solid malignancies were included. 177 patients (68%) had MD and 85 (32%) had non-measurable disease (NMD) at the time point of MTB presentation in accordance with RECIST v1.1. MD was not representative of the overall tumor burden in eleven patients (6%). The main reasons for NMD were lesions with longest diameter shorter than 10 mm (22%) and non-measurable peritoneal carcinomatosis (18%). Colorectal cancer and malignant melanoma displayed the highest rates of MD (> 75%). In contrast, gastric cancer, head and neck malignancies, and ovarian carcinoma had the lowest rates of MD (< 55%). In case of MD, the measurable lesions were representative of the overall tumor burden in the vast majority of cases (94%).

CONCLUSION

Approximately one third of cancer patients with advanced solid malignancies are not eligible for treatment response assessment in trials with endpoints ORR or DOR at the time of MTB presentation. The rate of patients eligible for trials with imaging endpoints differs significantly based on the underlying malignancy and should be taken under consideration during the planning of new precision oncology trials.

A deep learning-based system for survival benefit prediction of tyrosine kinase inhibitors and immune checkpoint inhibitors in stage IV non-small cell lung cancer patients: A multicenter, prognostic study

BACKGROUND

For clinical decision making, it is crucial to identify patients with stage IV non-small cell lung cancer (NSCLC) who may benefit from tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). In this study, a deep learning-based system was designed and validated using pre-therapy computed tomography (CT) images to predict the survival benefits of EGFR-TKIs and ICIs in stage IV NSCLC patients.

METHODS

This retrospective study collected data from 570 patients with stage IV EGFR-mutant NSCLC treated with EGFR-TKIs at five institutions between 2010 and 2021 (data of 314 patients were from a previously registered study), and 129 patients with stage IV NSCLC treated with ICIs at three institutions between 2017 and 2021 to build the ICI test dataset. Five-fold cross-validation was applied to divide the EGFR-TKI-treated patients from four institutions into training and internal validation datasets randomly in a ratio of 80%:20%, and the data from another institution was used as an external test dataset. An EfficientNetV2-based survival benefit prognosis (ESBP) system was developed with pre-therapy CT images as the input and the probability score as the output to identify which patients would receive additional survival benefit longer than the median PFS. Its prognostic performance was validated on the ICI test dataset. For diagnosing which patient would receive additional survival benefit, the accuracy of ESBP was compared with the estimations of three radiologists and three oncologists with varying degrees of expertise (two, five, and ten years). Improvements in the clinicians' diagnostic accuracy with ESBP assistance were then quantified.

FINDINGS

ESBP achieved positive predictive values of 80·40%, 75·40%, and 77·43% for additional EGFR-TKI survival benefit prediction using the probability score of 0·2 as the threshold on the training, internal validation, and external test datasets, respectively. The higher ESBP score (>0·2) indicated a better prognosis for progression-free survival (hazard ratio: 0·36, 95% CI: 0·19-0·68, p<0·0001) in patients on the external test dataset. Patients with scores >0·2 in the ICI test dataset also showed better survival benefit (hazard ratio: 0·33, 95% CI: 0·18-0·55, p<0·0001). This suggests the potential of ESBP to identify the two subgroups of benefiting patients by decoding the commonalities from pre-therapy CT images (stage IV EGFR-mutant NSCLC patients receiving additional survival benefit from EGFR-TKIs and stage IV NSCLC patients receiving additional survival benefit from ICIs). ESBP assistance improved the diagnostic accuracy of the clinicians with two years of experience from 47·91% to 66·32%, and the clinicians with five years of experience from 53·12% to 61·41%.

INTERPRETATION

This study developed and externally validated a preoperative CT image-based deep learning model to predict the survival benefits of EGFR-TKI and ICI therapies in stage IV NSCLC patients, which will facilitate optimized and individualized treatment strategies.

FUNDING

This study received funding from the National Natural Science Foundation of China (82001904, 81930053, and 62027901), and Key-Area Research and Development Program of Guangdong Province (2021B0101420005).

Clinical impact of post-progression survival in patients with locally advanced non-small cell lung cancer after chemoradiotherapy

BACKGROUND

The efficacy of first-line chemoradiotherapy for overall survival (OS) might be confounded by the subsequent treatments in patients with locally advanced non-small cell lung cancer (NSCLC). In this study, we assessed the associations of progression-free survival (PFS) and post-progression survival (PPS) with OS after chemoradiotherapy for locally advanced NSCLC using patient-level data.

PATIENTS AND METHODS

Between January 2011 and December 2018, 45 patients with locally advanced NSCLC who had received first-line chemoradiotherapy and in whom recurrence occurred were analysed. The associations of PFS and PPS with OS were analysed at the individual level.

RESULTS

Linear regression and Spearman rank correlation analyses revealed that PPS was strongly correlated with OS (r = 0.72, p < 0.05, R2 = 0.54), whereas PFS was moderately correlated with OS (r = 0.58, p < 0.05, R² = 0.34). The Glasgow prognostic score and liver metastases at recurrence were significantly associated with PPS (p < 0.001).

CONCLUSIONS

The current analysis of individual-level data of patients treated with first-line chemoradiotherapy implied that PPS had a higher impact on OS than PFS in patients with locally advanced NSCLC. Additionally, current perceptions indicate that treatment beyond progression after first-line chemoradiotherapy might strongly affect OS.

Course of postoperative relapse in non-small cell lung cancer is strongly associated with post-progression survival

Background

For early‐stage non‐small cell lung cancer (NSCLC), surgical resection is considered the most effective treatment strategy and curative treatment. Unfortunately, even after complete resection, almost half of all patients with stage I–IIIA NSCLC relapse and die. Although the possibility of a cure for postoperative recurrence of NSCLC is significantly low, the course of subsequent treatment can possibly affect overall survival (OS). Here, we examined the association of relapse‐free survival (RFS) and post‐progression survival (PPS) with OS in patients with postoperative recurrence of NSCLC.

Methods

We evaluated 128 patients with NSCLC who underwent complete resection between January 2007 and December 2018. The association between RFS and PPS on OS was examined at the patient level.

Results

Spearman's rank correlation and linear regression analyses revealed that PPS was strongly correlated with OS (r = 0.83, p < 0.05, R² = 0.72), whereas RFS was weakly associated with OS (r = 0.56, p < 0.05, R² = 0.37). Additionally, the performance status at relapse and administration of tyrosine kinase inhibitors were significantly correlated with PPS.

Conclusions

PPS was significantly more strongly correlated with OS than was RFS in patients with postoperative recurrence of NSCLC. These results suggest that therapy following postoperative recurrence affects OS. Therefore, it is necessary to validate these promising results in a large prospective study.

Post-Progression Survival Influences Overall Survival among Patients with Advanced Non-Small Cell Lung Cancer Undergoing First-Line Pembrolizumab Monotherapy

BACKGROUND

Among patients with non-small cell lung cancer (NSCLC), the impact of first-line treatment on overall survival (OS) may be influenced by subsequent therapies. Thus, using patient-level data, we assessed the relationships of progression-free survival (PFS) and post-progression survival (PPS) with OS among patients with high-programmed death-ligand 1 (PD-L1) expression undergoing first-line pembrolizumab monotherapy for NSCLC.

METHODS

We reviewed data from 133 patients with high PD-L1 expression undergoing first-line pembrolizumab monotherapy for NSCLC at 6 Japanese centers between February 2017 and December 2018. The correlations of PFS and PPS with OS were evaluated at the patient level.

RESULTS

Linear regression analyses and Spearman's rank correlation coefficient revealed that PPS was strongly correlated with OS (r = 0.76, p < 0.05, R2 = 0.65), while PFS was only moderately correlated with OS (r = 0.71, p < 0.05, and R2 = 0.4). Furthermore, PPS was significantly associated with performance status at the end of pembrolizumab monotherapy, as well as the use of platinum-based combination chemotherapy after pembrolizumab monotherapy (both p < 0.05).

CONCLUSIONS

Among patients with high PD-L1 expression undergoing first-line pembrolizumab monotherapy for NSCLC, PPS was more strongly correlated with OS, relative to the relationship between PFS and OS. Therefore, subsequent treatment appears to significantly influence OS in patients with disease progression following first-line pembrolizumab monotherapy.

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.

Post-Progression Survival Is Strongly Associated with Overall Survival in Patients Exhibiting Postoperative Relapse of Non-Small-Cell Lung Cancer Harboring Sensitizing EGFR Mutations

Background and Objective: Patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitizing epidermal growth factor receptor (EGFR) mutations show a good response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs). The subsequent treatments influence the evaluability of the efficacy of front-line therapy on overall survival (OS). Consequently, we evaluated the associations of relapse-free survival (RFS) and post-progression survival (PPS) with OS in patients who exhibited postoperative relapse of EGFR-mutated NSCLC. Materials and Methods: We analyzed the data of 35 patients with EGFR-mutated NSCLC who underwent complete resection between January 2007 and June 2019. The correlations of RFS and PPS with OS were evaluated at the individual patient level. Results: Linear regression and Spearman’s rank correlation analyses demonstrated that the PPS highly correlated with OS (r = 0.91, p < 0.05, R² = 0.85), whereas the RFS weakly associated with OS (r = 0.36, p < 0.05, R² = 0.25). Age and performance status at relapse were significantly associated with PPS. Conclusion: Overall, PPS was more strongly and significantly associated with OS than RFS. These results suggest that the OS of our cohort may be affected by treatments, besides postoperative relapse. However, larger-scale prospective studies are needed to confirm these results.

Prognostic Impact of the Advanced Lung Cancer Inflammation Index (ALI) in Metastatic Non-Small Cell Lung Cancer Treated with First Line Chemotherapy

Background:

The advanced lung cancer inflammation index (ALI) has been reported to predict the overall survival in patients with advanced non-small cell lung cancer (NSCLC). However, no previous studies have examined the prognostic significance of ALI in metastatic NSCLC treated with first line chemotherapy. The objective of this study was to explore the relationship between ALI and the prognosis of metastatic NSCLC treated with first line chemotherapy.

Materials and Methods:

Data of 109 metastatic NSCLC patients who had completed first line treatment with chemotherapy was collected. A multivariate flexible parametric proportional-hazards model with restricted cubic splines (RCS) was used to explore and identify the independent prognostic factors, including clinical potential factors and ALI for the overall survival. Multivariate regression analysis was used to evaluate the potential prognostic factors associated with short survival less than 6 months. The analysis of the restricted mean survival time (RMST) method was used to estimate the event-free time from zero to 18 months.

Results:

The median OS was 10.9 months (95%CI 9.57-13.18) and median PFS was 7.5 months (95%CI 6.85-8.00).The multivariate survival analyses revealed two prognostic factors for worse survival: Poor ECOG PS (HR46.90; 95%CI 2.90-758.73; p=0.007) and progressive disease after completing the first line chemotherapy treatment (HR 2.85; 95%CI1.18-6.88; p=0.02),whereas a low ALI <11 referred to a non-significant prognostic factor (HR 1.42; 95%CI 0.67-3.01; p=0.364).The results of the multivariate regression analysis revealed that the low ALI and progressive disease status were significantly associated with the short survival outcome (OR 5.12; 95%CI 1.11-23.65; p=0.037; OR 12.57; 95%CI 3.00-52.73; p=0.001).

Conclusions:

A low ALI was associated with the short survival in metastatic NSCLC treated with chemotherapy. However, using ALI as a prognostic factor only was still too limited. Other considerable clinical prognostic factors should also be used simultaneously, which would have strong significant prognostic impacts.

Clinical impact of post-progression survival on overall survival in patients receiving nivolumab monotherapy as a second-line treatment for advanced non-small cell lung cancer

Background

The effect of second‐line treatment on overall survival (OS) may be affected by subsequent treatment in patients with non‐small cell lung cancer (NSCLC); however, in such patients, the correlation between post‐progression survival (PPS) and OS is unclear. Our study assessed the correlation of progression‐free survival (PFS) and PPS with OS, using individual patient data, in advanced NSCLC patients who were treated with second‐line nivolumab monotherapy,

Methods

Between January 2016 and March 2019, we evaluated 92 NSCLC patients who received second‐line nivolumab treatment after first‐line platinum‐based combination chemotherapy. Using individual patient data, the correlations of PFS and PPS with OS were examined.

Results

Linear regression and Spearman rank correlation analysis demonstrated that PPS was strongly correlated with OS (r = 0.85, p < 0.05, R² = 0.75), while PFS was moderately correlated with OS (r = 0.65, p < 0.05, R² = 0.42). Performance status at the beginning of second‐line treatment, immune checkpoint inhibitor rechallenge, and the number of treatment regimens used post‐progression, after the second‐line treatment significantly correlated with PPS (p < 0.05). In advanced NSCLC patients who underwent second‐line treatment with nivolumab, in comparison to PFS, there was a stronger correlation between PPS and OS.

Conclusions

Our findings suggest that subsequent treatment for disease progression after a second‐line nivolumab treatment had a significant impact on OS.

Post-progression survival is highly linked to overall survival in patients with non-small-cell lung cancer harboring sensitive EGFR mutations treated with first-line epidermal growth factor receptor-tyrosine kinase inhibitors

Background

In patients with epidermal growth factor receptor (EGFR)‐mutated advanced non‐small‐cell lung cancer (NSCLC), epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) treatment has shown a good response. Subsequent treatments jeopardize the ability to determine the effect of first‐line chemotherapy on overall survival (OS). Therefore, using patient‐level data, we aimed to study the associations of progression‐free survival (PFS) and post‐progression survival (PPS) with OS after first‐line EGFR‐TKI treatment in patients with EGFR‐mutated NSCLC.

Methods

Between November 2006 and December 2016, we analyzed 92 patients with EGFR‐mutated NSCLC treated with first‐line EGFR‐TKI. The correlations of PFS and PPS with OS were analyzed for each patient.

Results

Spearman's rank correlation and linear regression analyzes showed that PPS correlated highly with OS (r = 0.85, P < 0.05, R² = 0.75), whereas PFS correlated weakly with OS (r = 0.76, P < 0.05, R² = 0.50). The best responses after first‐line and second‐line treatments were significantly associated with PPS.

Conclusions

PPS has a higher impact on OS than PFS in patients with EGFR‐mutated NSCLC treated with first‐line EGFR‐TKIs. These outcomes suggest that the OS in this patient group may be affected by treatments following first‐line chemotherapy; however, this remains to be verified in prospective trials.

Is time to progression associated with post-progression survival in previously treated metastatic non-small cell lung cancer with BRAF V600E mutation? A secondary analysis of phase II clinical trial data

OBJECTIVE

Longer time to progression (TTP) is associated with prolonged post-progression survival (PPS) in anaplastic lymphoma kinase+non-small cell lung cancer (NSCLC). This study evaluated whether TTP is associated with PPS among previously treated patients with metastatic v-Raf murine sarcoma viral oncogene homolog B V600E NSCLC receiving dabrafenib as monotherapy or in combination with trametinib.

DESIGN

Secondary analysis of phase II clinical trial data.

SETTING

Patients who experienced disease progression treated with dabrafenib monotherapy or in combination with trametinib as second line or later in an open-label, non-randomised, phase II study.

PRIMARY OUTCOME MEASURES

The primary outcome was the TTP-PPS association. PPS was assessed with Kaplan-Meier analysis among patients with shorter versus longer TTP (< or ≥6 months). The TTP-PPS association was quantified in the Cox models adjusting for clinical covariates.

RESULTS

Of the 84 included patients who progressed on dabrafenib monotherapy (n=57) or combination therapy (n=27), 60 (71%) died during post-progression follow-up. Patients with TTP ≥6 months experienced significantly longer PPS compared with those with TTP <6 months (median PPS: 9.5 vs 2.7 months, log-rank p<0.001). Each 3 months of longer TTP was associated with a 32% lower hazard of death following progression (HR 0.68, 95% CI 0.52 to 0.88) in the multivariable Cox model. Similar associations were seen in each treatment arm.

CONCLUSION

A longer TTP duration after treatment with dabrafenib monotherapy or combination therapy was associated with significantly longer PPS duration.

TRIAL REGISTRATION NUMBER

NCT01336634; Post-results.

Clinical significance of post-progression survival in lung cancer

Progression-free survival (PFS) and overall survival (OS) are two common endpoints in cancer trials. OS is usually preferred, because it is reliable, precise, meaningful, and can easily be documented. However, subsequent lines of therapy might confound the effects of first-line treatment on OS. Whether PFS or OS is the more appropriate endpoint in clinical trials of metastatic cancer remains controversial. Previous reports on lung cancer have shown that an increase in PFS does not necessarily result in an increase in OS; however, post-progression survival (PPS) is strongly associated with OS after early-line treatment. The significance of PPS after first and second-line therapy at the individual level in patients with advanced lung cancer has also recently been reported. Findings of previous reports indicate that PPS is highly associated with OS after first and second-line chemotherapy in patients with advanced non-small cell lung cancer and small cell lung cancer, whereas PFS is only moderately associated with OS. Therefore, subsequent treatment after disease progression following early-line treatments may greatly influence OS. This review demonstrates that even in advanced lung cancer, PPS, rather than PFS, has become more strongly associated with OS over the years, potentially because of intensive post-study treatments. As a result of the increasing impact of PPS on OS, a PFS-related advantage does not necessarily indicate an OS-related advantage. Thus, the prolongation of PPS might limit the classical role of OS for assessing true efficacy derived from early-line chemotherapy in future clinical trials.

Post-Progression Survival Associated with Overall Survival in Patients with Advanced Non-Small-Cell Lung Cancer Receiving Docetaxel Monotherapy as Second-Line Chemotherapy

BACKGROUND

In patients with non-small-cell lung cancer (NSCLC), the effects of second-line chemotherapy on overall survival (OS) might be confounded by subsequent therapies. Therefore, using individual-level data, we aimed to determine the relationships between progression-free survival (PFS) and post-progression survival (PPS) with OS in patients with advanced NSCLC treated with docetaxel monotherapy as second-line chemotherapy.

METHODS

Between April 2002 and December 2014, data from 86 patients with advanced NSCLC who underwent second-line docetaxel monotherapy following first-line treatment with platinum combination chemotherapy were analyzed. The relationships of PFS and PPS with OS were analyzed at the individual level.

RESULTS

Spearman rank correlation and linear regression analyses showed that PPS was strongly associated with OS (r = 0.86, p < 0.05, R2 = 0.93), whereas PFS was moderately correlated with OS (r = 0.50, p < 0.05, R2 = 0.21). Performance status at the end of second-line treatment and the number of regimens after progression beyond second-line chemotherapy were significantly associated with PPS (p < 0.05).

CONCLUSIONS

In patients with advanced NSCLC with unknown oncogenic driver mutations undergoing docetaxel monotherapy as second-line chemotherapy, when compared with PFS, PPS had a stronger association with OS. This finding suggests that subsequent treatment after disease progression following second-line docetaxel monotherapy has a significant influence on OS.

Validation of surrogate endpoints in advanced solid tumors: systematic review of statistical methods, results, and implications for policy makers

OBJECTIVES

Licensing of, and coverage decisions on, new therapies should rely on evidence from patient-relevant endpoints such as overall survival (OS). Nevertheless, evidence from surrogate endpoints may also be useful, as it may not only expedite the regulatory approval of new therapies but also inform coverage decisions. It is, therefore, essential that candidate surrogate endpoints be properly validated. However, there is no consensus on statistical methods for such validation and on how the evidence thus derived should be applied by policy makers.

METHODS

We review current statistical approaches to surrogate-endpoint validation based on meta-analysis in various advanced-tumor settings. We assessed the suitability of two surrogates (progression-free survival [PFS] and time-to-progression [TTP]) using three current validation frameworks: Elston and Taylor's framework, the German Institute of Quality and Efficiency in Health Care's (IQWiG) framework and the Biomarker-Surrogacy Evaluation Schema (BSES3).

RESULTS

A wide variety of statistical methods have been used to assess surrogacy. The strength of the association between the two surrogates and OS was generally low. The level of evidence (observation-level versus treatment-level) available varied considerably by cancer type, by evaluation tools and was not always consistent even within one specific cancer type.

CONCLUSIONS

Not in all solid tumors the treatment-level association between PFS or TTP and OS has been investigated. According to IQWiG's framework, only PFS achieved acceptable evidence of surrogacy in metastatic colorectal and ovarian cancer treated with cytotoxic agents. Our study emphasizes the challenges of surrogate-endpoint validation and the importance of building consensus on the development of evaluation frameworks.

Prognostic value of early response assessment using 18F-FDG PET/CT in chemotherapy-treated patients with non-small-cell lung cancer

OBJECTIVE

We aimed to evaluate the prognostic value of early response assessment using a volumetric fluorine-18-fluorodeoxyglucose (F-FDG) PET analysis in chemotherapy-treated patients with non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

We retrospectively reviewed 33 patients with NSCLC who received first-line chemotherapy and performed F-FDG PET/computed tomography before (baseline PET) and after two cycles of chemotherapy (interim PET). The maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of the total malignant lesion were measured in baseline (SUV1 and MTV1) and interim (SUV2 and MTV2) PET images, and percentage changes in SUVmax (ΔSUV) and MTV (ΔMTV) were calculated between the two images. We compared PET parameters and clinicopathologic variables in terms of the 2-year overall survival (OS).

RESULTS

The median follow-up period was 14.3 months and the 2-year OS was 31%. In PET images, the mean SUV1, MTV1, SUV2, MTV2, ΔSUV, and ΔMTV were 13.1±4.5, 307.9±340.0 cm, 9.5±5.1, 180.4±29.6 cm, 27±28%, and 42±65%, respectively. In univariable analysis, M stage, TNM stage, and all six PET parameters associated significantly with OS. Both the MTV1 and the ΔMTV were tested against OS controlling for M stage, one at time, and the effect remained significant in multivariable analyses.

CONCLUSION

A smaller baseline MTV and greater decrease in MTV between baseline and interim PET images are associated with a significantly prolonged OS. A volume-based F-FDG PET analysis would facilitate prediction of clinical outcome and identification of treatment-resistant patients early during chemotherapy and could thus be used in personalized treatment approaches for patients with NSCLC.

Relationship between Overall Survival and Response or Progression-Free Survival in Advanced Non-Small Cell Lung Cancer Patients Treated with Anti-PD-1/PD-L1 Antibodies

INTRODUCTION

Alternative predictive end points for overall survival (OS), such as tumor response and progression-free survival (PFS), are useful in the early detection of drug efficacy; however, they have not been fully investigated in patients with advanced NSCLC treated with anti-programmed death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) antibodies.

METHODS

In a systematic review of the reported prospective clinical trials, data for response rate, median PFS, and median OS were extracted from 12 arms in 10 reported clinical trials using anti-PD-1/PD-L1 antibody, and their correlation was investigated. In a retrospective analysis at our institution, OS was compared according to tumor response on 5- to 9-week computed tomography scans and status of being progression-free at 8, 16, and 24 weeks by landmark analysis in 71 patients with advanced NSCLC treated with anti-PD-1/PD-L1 antibodies between 2013 and 2015.

RESULTS

In a systematic review, moderate correlations between median OS and median PFS (p = 0.120, r = 0.473) and between median OS and response rate (p = 0.141, r = 0.452) were identified using the Spearman correlation coefficient, although these correlations were not statistically significant. In a retrospective analysis of patients treated at our institution, disease control (partial response [PR]/stable disease versus progressive disease/not evaluable), and progression-free status at 8, 16, and 24 weeks significantly predicted OS (Cox proportional hazards model, PR/stable disease versus progressive disease/not evaluable, p = 0.0104, HR = 3.041; 8-week progression-free yes versus no, p = 0.0183, HR = 2.684; 16-week progression-free yes versus no, p = 0.0036, HR = 4.009; and 24-week progression-free yes versus no, p = 0.0002, HR = 12.726).

CONCLUSIONS

Both disease control (PR plus stable disease status) and landmark progression-free survival were correlated with OS, with the longer interval landmark PFS being the best predictor of survival in patients with NSCLC treated with anti-PD-1/PD-L1 antibodies.

Clinical impact of post-progression survival on overall survival in elderly patients with extensive disease small-cell lung cancer

Background

The effects of first‐line chemotherapy on overall survival (OS) might be confounded by subsequent therapies in patients with small‐cell lung cancer (SCLC). Therefore, the objective of our study was to determine the relationships between progression‐free survival (PFS) or post‐progression survival (PPS) and OS after first‐line chemotherapy in elderly patients with extensive disease‐SCLC (ED‐SCLC), using individual level data.

Methods

Between July 1998 and December 2014, we analyzed 57 cases of elderly patients with ED‐SCLC who were treated with carboplatin and etoposide as first‐line chemotherapy. The relationships between PFS and PPS with OS were analyzed at an individual level.

Results

Spearman rank correlation and linear regression analyses showed that PPS was strongly correlated with OS (r = 0.92, P < 0.05, R² = 0.83) and PFS was moderately correlated with OS (r = 0.76, P < 0.05, R² = 0.25). The best response at second‐line treatment and the number of regimens after progression beyond first‐line chemotherapy were both significantly associated with PPS (P < 0.05).

Conclusions

PPS has a stronger impact on OS than PFS in elderly ED‐SCLC patients after first‐line chemotherapy. In addition, the response at second‐line treatment and the number of additional regimens after first‐line treatment are significant independent prognostic factors for PPS. These results suggest that OS in elderly ED‐SCLC patients may be influenced by treatments subsequent to first‐line chemotherapy; however, this remains to be verified with prospective studies.

Clinical Significance of the Relationship between Progression-Free Survival or Postprogression Survival and Overall Survival in Patients with Extensive Disease-Small-Cell Lung Cancer Treated with Carboplatin plus Etoposide

Background. The effects of first-line chemotherapy on overall survival (OS) might be confounded by subsequent therapies in patients with small-cell lung cancer (SCLC). Therefore, by using individual-level data, we aimed to determine the relationships between progression-free survival (PFS) or postprogression survival (PPS) and OS after first-line chemotherapies in patients with extensive disease-SCLC (ED-SCLC) treated with carboplatin plus etoposide. Methods. Between July 1998 and December 2014, we analyzed 63 cases of patients with ED-SCLC who were treated with carboplatin and etoposide as first-line chemotherapy. The relationships of PFS and PPS with OS were analyzed at the individual level. Results. Spearman rank correlation analysis and linear regression analysis showed that PPS was strongly correlated with OS (r = 0.90, p < 0.05, and R² = 0.71) and PFS was moderately correlated with OS (r = 0.72, p < 0.05, and R² = 0.62). Type of relapse (refractory/sensitive) and the number of regimens administered after disease progression after the first-line chemotherapy were both significantly associated with PPS (p < 0.05). Conclusions. PPS has a stronger relationship with OS than does PFS in ED-SCLC patients who have received first-line chemotherapy. These results suggest that treatments administered after first-line chemotherapy affect the OS of ED-SCLC patients treated with carboplatin plus etoposide.

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.

Clinical impact of post-progression survival on overall survival in patients with limited-stage disease small cell lung cancer after first-line chemoradiotherapy

Background

The effects of first-line chemoradiotherapy on overall survival (OS) may be confounded by subsequent lines of therapy in patients with limited-stage disease small cell lung cancer (LD-SCLC). Therefore, we aimed to determine the relationships between progression-free survival (PFS), post-progression survival (PPS) and OS after first-line chemoradiotherapy in LD-SCLC patients.

Patients and methods.

We retrospectively analyzed 71 LD-SCLC patients with performance status (PS) 0–2 who received first-line chemoradiotherapy and had disease recurrence between September 2002 and March 2013 at Shizuoka Cancer Center (Shizuoka, Japan). We determined the correlation between PFS and OS and between PPS and OS at the individual level. In addition, we performed univariate and multivariate analyses to identify significant prognostic factors of PPS.

Results

OS is more strongly correlated with PPS (Spearman’s r = 0.86, R² = 0.72, p < 0.05) than PFS (Spearman’s r = 0.46, R² = 0.38, p < 0.05). In addition, the response to second-line treatments, the presence of distant metastases at recurrence and the number of additional regimens after first-line chemoradiotherapy were significant independent prognostic factors for PPS.

Conclusions

PPS has more impact on OS than PFS in recurrent LD-SCLC patients with good PS at beginning of the treatment. Moreover, treatments administered after first-line chemoradiotherapy may affect their OS. However, larger multicenter studies are needed to validate these findings.

Magnitude of the benefit of progression-free survival as a potential surrogate marker in phase 3 trials assessing targeted agents in molecularly selected patients with advanced non-small cell lung cancer: systematic review

Background

In evaluation of the clinical benefit of a new targeted agent in a phase 3 trial enrolling molecularly selected patients with advanced non-small cell lung cancer (NSCLC), overall survival (OS) as an endpoint seems to be of limited use because of a high level of treatment crossover for ethical reasons. A more efficient and useful indicator for assessing efficacy is needed.

Methods and Findings

We identified 18 phase 3 trials in the literature investigating EGFR-tyrosine kinase inhibitor (TKIs) or ALK-TKIs, now approved for use to treat NSCLC, compared with standard cytotoxic chemotherapy (eight trials were performed in molecularly selected patients and ten using an “all-comer” design). Receiver operating characteristic analysis was used to identify the best threshold by which to divide the groups. Although trials enrolling molecularly selected patients and all-comer trials had similar OS-hazard ratios (OS-HRs) (0.99 vs. 1.04), the former exhibited greater progression-free survival-hazard ratios (PFS-HR) (mean, 0.40 vs. 1.01; P<0.01). A PFS-HR of 0.60 successfully distinguished between the two types of trials (sensitivity 100%, specificity 100%). The odds ratio for overall response was higher in trials with molecularly selected patients than in all-comer trials (mean: 6.10 vs. 1.64; P<0.01). An odds ratio of 3.40 for response afforded a sensitivity of 88% and a specificity of 90%.

Conclusion

The notably enhanced PFS benefit was quite specific to trials with molecularly selected patients. A PFS-HR cutoff of ∼0.6 may help detect clinical benefit of molecular targeted agents in which OS is of limited use, although desired threshold might differ in an individual trial.

Progression-free survival, post-progression survival, and tumor response as surrogate markers for overall survival in patients with extensive small cell lung cancer

OBJECTIVES

The effects of first-line chemotherapy on overall survival (OS) might be confounded by subsequent therapies in patients with small cell lung cancer (SCLC). We examined whether progression-free survival (PFS), post-progression survival (PPS), and tumor response could be valid surrogate endpoints for OS after first-line chemotherapies for patients with extensive SCLC using individual-level data.

METHODS

Between September 2002 and November 2012, we analyzed 49 cases of patients with extensive SCLC who were treated with cisplatin and irinotecan as first-line chemotherapy. The relationships of PFS, PPS, and tumor response with OS were analyzed at the individual level.

RESULTS

Spearman rank correlation analysis and linear regression analysis showed that PPS was strongly correlated with OS (r = 0.97, p < 0.05, R(2)= 0.94), PFS was moderately correlated with OS (r = 0.58, p < 0.05, R(2)= 0.24), and tumor shrinkage was weakly correlated with OS (r = 0.37, p < 0.05, R(2)= 0.13). The best response to second-line treatment, and the number of regimens employed after progression beyond first-line chemotherapy were both significantly associated with PPS ( p ≤ 0.05).

CONCLUSION

PPS is a potential surrogate for OS in patients with extensive SCLC. Our findings also suggest that subsequent treatment after disease progression following first-line chemotherapy may greatly influence OS.

Surrogate endpoints for overall survival in advanced non-small-cell lung cancer patients with mutations of the epidermal growth factor receptor gene

Subsequent therapies confound the ability to discern the effect of first-line chemotherapy on overall survival (OS). We investigated whether progression-free survival (PFS), post-progression survival (PPS) and tumor response were valid surrogate endpoints for OS following first-line chemotherapy in individual patients with advanced non-small-cell lung cancer (NSCLC) harboring sensitive epidermal growth factor receptor gene mutations. We retrospectively analyzed 35 patients with advanced NSCLC treated with first-line gefitinib. The associations of PFS, PPS and tumor response with OS were analyzed. PPS was found to be strongly correlated with OS, unlike PFS and tumor shrinkage. The factors significantly associated with PPS were performance status (PS) after first-line treatment, best response to second-line treatment and number of regimens used after disease progression. PPS may be a surrogate for OS in this patient population and further therapy after disease progression following first-line chemotherapy may significantly affect OS. However, a larger study is required to validate these results.

Relationship between progression-free survival and overall survival in patients with advanced non-small cell lung cancer treated with anticancer agents after first-line treatment failure

AIM

The hazard ratio of progression-free survival (PFS-HR) generally does not reflect that of overall survival (OS-HR) in advanced non-small cell lung cancer (NSCLC) patients treated with first-line therapy. Short survival post-progression (SPP) better reflects the PFS-HR and OS-HR in simulations. We aimed to evaluate whether the PFS-HR reflects the OS-HR in NSCLC clinical trials for post-first-line treatments.

METHOD

We reviewed clinical studies of post-first-line anticancer agents for NSCLC. We examined the sample size of the experimental arm (EA), median PFS (mPFS) or median time to progression in the EA, median overall survival (mOS) in the EA, the PFS-HR and the OS-HR. SPP was defined as the difference between mOS and mPFS. The association between mPFS and SPP, mPFS and mOS, and the PFS-HR and OS-HR was tested. We sought for the optimal point of correlation of PFS-HR and OS-HR by every 1 month of SPP.

RESULTS

We identified 32 trials (34 arms). mPFS and mOS were weakly correlated (correlation coefficient [r] = 0.376; P = 0.0286). The PFS-HR and OS-HR were also moderately correlated (r = 0.415; P = 0.015). The maximum r value was 0.770 (SPP < 6 months; P < 0.0001) when we tested the associations between the PFS-HR and OS-HR for SPP using 1-month increments. The estimated regression equation at this point was OS-HR = 0.679 × (PFS-HR) + 0.349.

CONCLUSION

The PFS-HR and OS-HR were strongly correlated in advanced NSCLC patients treated with post-first-line anticancer agents, with a SPP of less than 6 months.

Metabolic burden measured by (18)f-fluorodeoxyglucose positron emission tomography/computed tomography is a prognostic factor in patients with small cell lung cancer

Purpose

Evidence regarding the usefulness of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in predicting the prognosis of non-small cell lung cancer is increasing. However, data on small cell lung cancer (SCLC) are scarce. The aim of this study was to evaluate the prognostic value of metabolic parameters measured using ¹⁸F-FDG PET/CT in patients with SCLC.

Materials and Methods

We conducted a retrospective review of 114 patients with pathologically proven SCLC (26 cases of limited disease and 88 cases of extensive disease) who underwent pretreatment ¹⁸F-FDG PET/CT. The maximal SUV (SUV_max) was used quantitatively for determination of FDG PET activity. The SUV_max of the primary tumor (primary SUV_max), the sum of SUV_max values of malignant lesions (SUV_sum), and the mean SUV_max of malignant lesions were calculated.

Results

The patient population was subdivided using a median SUV_sum value of 24.6. High SUV_sum showed a significant association with known factors for poor prognosis, including higher neuron-specific enolase (p=0.010), CYFRA 21-1 (p=0.014), and extensive disease status (p=0.007). Patients with high SUV_sum had significantly shorter median overall survival (6.6 months vs. 13.0 months, p<0.001) and progression-free survival (5.2 months vs. 8.0 months, p<0.001) than patients with low SUV_sum. Results of multivariate analysis showed that SUV_sum, chemotherapy cycles, and the response to first-line treatment were significant prognostic factors of survival. In contrast, mean SUV_max and primary SUV_max were not significant predictors of survival.

Conclusion

In this study, metabolic burden represented by SUV_sum from pretreatment ¹⁸F-FDG PET/CT was an independent prognostic factor in patients with SCLC.

Correlation between overall survival and other endpoints in clinical trials of second-line chemotherapy for patients with advanced gastric cancer

BACKGROUND

The correlation between progression-free survival (PFS) or time to progression (TTP) and overall survival (OS) has been evaluated in patients with advanced gastric cancer (AGC) who received first-line chemotherapy. No corresponding analysis has been done in patients who have undergone second-line chemotherapy.

METHODS

We evaluated the correlation between PFS, TTP, objective response rate (ORR), disease control rate (DCR), and OS in patients with AGC who underwent second-line chemotherapy. Correlations were evaluated by Spearman rank correlation coefficient (ρ).

RESULTS

Sixty-four trials, including 10 randomized studies, were selected for analysis. Median PFS/TTP moderately correlated with OS (ρ = 0.56). The correlation tended to be stronger in non-Asian trials (ρ = 0.74) than in Asian trials (ρ = 0.37). ORR and DCR did not strongly correlate with OS (ρ = 0.38 for ORR; ρ = 0.54 for DCR). The hazard ratio of PFS and OS in each of the arms of the 10 randomized studies also showed a low correlation (ρ = 0.36).

CONCLUSIONS

PFS/TTP, ORR, and DCR did not correlate sufficiently with OS to be used as surrogate endpoints in patients with AGC who have undergone second-line chemotherapy. Further research is needed based on individual patient data from ongoing randomized trials.

Progression-free survival as a surrogate endpoint for overall survival in glioblastoma: a literature-based meta-analysis from 91 trials

Background

The aim of this study was to determine correlations between progression-free survival (PFS) and the objective response rate (ORR) with overall survival (OS) in glioblastoma and to evaluate their potential use as surrogates for OS.

Method

Published glioblastoma trials reporting OS and ORR and/or PFS with sufficient detail were included in correlative analyses using weighted linear regression.

Results

Of 274 published unique glioblastoma trials, 91 were included. PFS and OS hazard ratios were strongly correlated; R² = 0.92 (95% confidence interval [CI], 0.71–0.99). Linear regression determined that a 10% PFS risk reduction would yield an 8.1% ± 0.8% OS risk reduction. R² between median PFS and median OS was 0.70 (95% CI, 0.59–0.79), with a higher value in trials using Response Assessment in Neuro-Oncology (RANO; R² = 0.96, n = 8) versus Macdonald criteria (R² = 0.70; n = 83). No significant differences were demonstrated between temozolomide- and bevacizumab-containing regimens (P = .10) or between trials using RANO and Macdonald criteria (P = .49). The regression line slope between median PFS and OS was significantly higher in newly diagnosed versus recurrent disease (0.58 vs 0.35, P = .04). R² for 6-month PFS with 1-year OS and median OS were 0.60 (95% CI, 0.37–0.77) and 0.64 (95% CI, 0.42–0.77), respectively. Objective response rate and OS were poorly correlated (R² = 0.22).

Conclusion

In glioblastoma, PFS and OS are strongly correlated, indicating that PFS may be an appropriate surrogate for OS. Compared with OS, PFS offers earlier assessment and higher statistical power at the time of analysis.

Progression-free survival and post-progression survival in patients with advanced gastric cancer treated with first-line chemotherapy

PURPOSE

The impact of post-progression survival (PPS) on the overall survival (OS) of patients with advanced gastric cancer (AGC) has not yet been reported in detail. We analyzed prospectively collected data from AGC patients who received first-line chemotherapy including fluoropyrimidine plus platinum.

METHODS

We partitioned OS into progression-free survival (PFS) and PPS in each patient and analyzed correlations between OS and either PFS or PPS using the Spearman rank correlation coefficient (ρ).

RESULTS

A total of 291 AGC patients met the inclusion criteria with median PFS, PPS, and OS of 5.3, 8.1, and 14.8 months, respectively. PFS and OS for each patient showed a correlation of ρ = 0.75 [95% confidence interval (CI) 0.69-0.81]. PPS and OS showed a correlation of ρ = 0.87 (95% CI 0.84-0.91). According to multivariate analysis, performance status at progression, PFS of first-line chemotherapy, and use of second-line chemotherapy were independently associated with PPS.

CONCLUSIONS

These results indicate that both PFS and PPS are correlated with OS in first-line chemotherapy for AGC, suggesting the importance of reporting detailed patient characteristics and treatment course after disease progression in clinical trials of first-line chemotherapy for AGC.

Time-dependent endpoints as predictors of overall survival in multiple myeloma

Background

Supporting health care sector decisions using time-dependent endpoints (TDEs) such as time to progression (TTP), progression-free survival (PFS), and event-free survival (EFS) remains controversial. This study estimated the quantitative relationship between median TDE and median overall survival (OS) in multiple myeloma (MM) patients.

Methods

Studies (excluding allogeneic transplantation) published from 1970 to 2011 were systematically searched (PubMed). The nonparametric Spearman’s rank correlation coefficient measured the association between median TDE and OS. The quantitative relationship between TDEs and OS was estimated with a two-step approach to a simultaneous Tobit model.

Results

We identified 153 studies: 230 treatment arms, 22,696 patients and mean study duration of 3.8 years. Mean of median TDEs was 22.5 months and median OS was 39.1 months. Correlation coefficients of median TTP, PFS, and EFS with median OS were 0.51 (P = 0.003), 0.75 (P < 0.0001), and 0.84 (P < 0.0001), respectively. We estimate a 2.5 month (95% confidence interval, 1.7–3.2) increase in median OS for each additional month reported for median TDEs. There was no evidence that this relationship differed by type of surrogate.

Conclusion

TDEs predict OS in MM patients; this relationship may be valuable in clinical trial design, drug comparisons, and economic evaluation.

Progression-free survival and overall survival in phase III trials of molecular-targeted agents in advanced non-small-cell lung cancer

BACKGROUND

We examined how crossover therapy might affect the association between progression-free survival (PFS) and overall survival (OS) in non-small cell lung cancer (NSCLC).

METHODS

We extracted PFS- and OS-hazard ratios (HRs) in phase III trials of molecular-targeted agents for advanced NSCLC. Their relationship was modeled in a linear function with the coefficient of determination (R-squared) to assess the correlation between PFS and OS.

RESULTS

Thirty-four trials with 35 pairs for the investigational and reference arms were identified (24,158 patients). Overall, there was little correlation between PFS- and OS-HRs (R-squared = 0.14), suggesting PFS-HR could account only for 14% of variation in OS-HR. The median proportion of crossover therapy per trial was 20%. If patients seldom crossed over (none or <1%), the association between PFS- and OS-HRs was strong (R-squared = 0.69). When the proportion of crossover was ≥1%, however, R-squared declined considerably (≥1% to <20% crossover, R-squared = 0.27; ≥20% to <40%, R-squared = 0.06; and ≥40%, R-squared = 0.27).

CONCLUSIONS

A PFS advantage seldom is associated with an OS advantage any longer. Our analysis suggests this is due to a high level of crossover now that an increasing number of active agents are available for NSCLC.

Treatment-related death in patients with small-cell lung cancer in phase III trials over the last two decades

Introduction

Treatment-related death (TRD) remains a serious problem in small-cell lung cancer (SCLC), despite recent improvements in supportive care. However, few studies have formally assessed time trends in the proportion of TRD over the past two decades. The aim of this study was to determine the frequency and pattern of TRD over time.

Methods

We examined phase 3 trials conducted between 1990 and 2010 to address the role of systemic treatment for SCLC. The time trend was assessed using linear regression analysis.

Results

In total, 97 trials including nearly 25,000 enrolled patients were analyzed. The overall TRD proportion was 2.95%. Regarding the time trend, while it was not statistically significant, it tended to decrease, with a 0.138% decrease per year and 2.76% decrease per two decades. The most common cause of death was febrile neutropenia without any significant time trend in its incidence over the years examined (p = 0.139). However, deaths due to febrile neutropenia as well as all causes in patients treated with non-platinum chemotherapy increased significantly (p = 0.033).

Conclusions

The overall TRD rate has been low, but not negligible, in phase III trials for SCLC over the past two decades.

Influence of the timing of tumor regression after the initiation of chemoradiotherapy on prognosis in patients with limited-disease small-cell lung cancer achieving objective response

PURPOSE

Chemoradiotherapy (CHRT) yields a favorable antitumor activity in patients with limited-stage small-cell lung cancer (LD-SCLC) with a response rate of around 80%. Even in such responders, the majority recur, indicating the importance of identifying a subset of patients with a poor outcome earlier through the treatment. We investigated whether the timing of obtaining tumor regression with the CHRT could affect the prognosis in LD-SCLC patients who finally achieved the objective response through the treatment.

PATIENTS AND METHODS

We retrospectively reviewed medical charts of 70 LD-SCLC patients who obtained complete response (CR) or partial response (PR) with the 3 or 4 cycles of first-line CHRT between 1988 and 2006.

RESULTS

In the whole 70 patients with CR/PR, the median survival time and median progression free survival (PFS) were 39.6 and 12.3months, respectively. Fifty-two (74.3%) of the 70 patients entered CR/PR after the first cycle of CHRT, and their 2-year survival rates were significantly longer than that in the remaining 18 patients without entering CR/PR yet at the end of first cycle (72.3% and 7.1%, respectively, p<0.001). Cox regression analysis showed that the early response to the treatment was a significant prognostic factors (hazard ratio=0.098; 95% confidence interval=0.036-0.269). Regarding PFS, similar findings were observed.

CONCLUSIONS

Patients without entering CR/PR yet after the first course had a poorer outcome even though the objective response was finally confirmed through the treatment. Development of more effective treatments for these high-risk patients is warranted to improve their poor prognosis.

Factors associated with long-term survival of patients with advanced non-small cell lung cancer

BACKGROUND AND OBJECTIVE

Only a small proportion of patients with advanced non-small cell lung cancer (NSCLC) have a life expectancy greater than 2 years. The aim of this study was to identify the factors associated with long-term survival of patients with advanced NSCLC.

METHODS

Patients who had received chemotherapy for stage IIIb or IV NSCLC that was not amenable to radiotherapy were studied retrospectively. Data were gathered prospectively from a comprehensive database. Long-term survivors (>2 years) were compared with the other patients, with respect to clinical, biological and tumour-node-metastasis criteria.

RESULTS

Data for 245 consecutive patients were collected. Thirty nine patients (15.9%) survived for more than 2 years. Long-term survivors were more likely to have had metastases at fewer sites (P = 0.008), an absence of bone metastases (P = 0.01), a performance status (PS) of 0-1 at first progression of the tumour (P = 0.002), a tumour that was controlled with first (P < 0.0001) and second-line (P = 0.004) chemotherapy, maintenance therapy (P = 0.001), curative surgery (P < 0.0001), time to first progression of the tumour of >3 months (P < 0.0001), normal LDH levels at diagnosis (P = 0.049), and a haemoglobin concentration >110 g/L at first progression of the tumour (P = 0.02). In multivariate analysis, surgery, maintenance treatment, time to first progression of the tumour of >3 months, a PS of 0-1 at first progression, the number of chemotherapy agents received, and LDH levels, were significant predictors of long-term survival.

CONCLUSIONS

  Assessment of these factors, and the use of maintenance therapy, when possible, may identify a population of patients with NSCLC that is likely to have a prolonged life expectancy.

Stopping rules employing response rates, time to progression, and early progressive disease for phase II oncology trials

Background

Response rate (RR), the most common early means of assessing oncology drugs, is not suitable as the sole endpoint for phase II trials of drugs which induce disease stability but not regression. Time to progression (TTP) may be more sensitive to such agents, but induces recruitment delays in multistage studies. Early progressive disease (EPD) is the earliest signal of time to progression, but is less intuitive to investigators, To study drugs with unknown anti-tumour effect, we designed the Combination Stopping Rule (CSR), which allows investigators to establish a hypothesis using RR and TTP, while the program also employs early progressive disease (EPD) to assess for drug inactivity during the first stage of study accrual.

Methods

A computer program was created to generate stopping rules based on specified error rates, trial size, and RR and median TTP of interest and disinterest for a two-stage phase II trial. Rules were generated for stage II such that the null hypothesis (H_nul) was rejected if either RR or TTP met desired thresholds, and accepted if both did not. Assuming an exponential distribution for progression, EPD thresholds were determined based on specified TTP values. Stopping rules were generated for stage I such that H_nul was accepted and the study stopped if both RR and EPD were unacceptable.

Results

Patient thresholds were generated for RR, median TTP, and EPD which achieved specified error rates and which allowed early stopping based on RR and EPD. For smaller proportional differences between interesting and disinteresting values of RR or TTP, larger trials are required to maintain alpha error, and early stopping is more common with a larger first stage.

Conclusion

Stopping rules are provided for phase II trials for drugs which have either a desirable RR or TTP. In addition, early stopping can be achieved using RR and EPD.

Role of survival post-progression in phase III trials of systemic chemotherapy in advanced non-small-cell lung cancer: a systematic review

Background

In advanced non-small-cell lung cancer (NSCLC), with the increasing number of active compounds available in salvage settings, survival after progression to first-line chemotherapy seems to have improved. A literature survey was conducted to examine whether survival post-progression (SPP) has improved over the years and to what degree SPP correlates with overall survival (OS).

Methods and Findings

Median progression-free survival (MPFS) time and median survival time (MST) were extracted in phase III trials of first-line chemotherapy for advanced NSCLC. SPP was pragmatically defined as the time interval of MST minus MPFS. The relationship between MPFS and MST was modeled in a linear function. We used the coefficient of determination (r²) to assess the correlation between them. Seventy trials with 145 chemotherapy arms were identified. Overall, median SPP was 4.7 months, and a steady improvement in SPP was observed over the 20 years (9.414-day increase per year; p<0.001) in parallel to the increase in MST (11.253-day increase per year; p<0.001); MPFS improved little (1.863-day increase per year). Overall, a stronger association was observed between MST and SPP (r² = 0.8917) than MST and MPFS time (r² = 0.2563), suggesting SPP and MPFS could account for 89% and 25% of the variation in MST, respectively. The association between MST and SPP became closer over the years (r² = 0.4428, 0.7242, and 0.9081 in 1988–1994, 1995–2001, and 2002–2007, respectively).

Conclusions

SPP has become more closely associated with OS, potentially because of intensive post-study treatments. Even in advanced NSCLC, a PFS advantage is unlikely to be associated with an OS advantage any longer due to this increasing impact of SPP on OS, and that the prolongation of SPP might limit the original role of OS for assessing true efficacy derived from early-line chemotherapy in future clinical trials.

Leukemia-free survival as a surrogate end point for overall survival in the evaluation of maintenance therapy for patients with acute myeloid leukemia in complete remission

BACKGROUND

In trials designed to evaluate new therapies for hematologic malignancies, end points such as leukemia-free survival are often used as surrogates for overall survival in acute leukemia. We aimed to assess whether leukemia-free survival is an acceptable statistical surrogate for overall survival when applied to remission maintenance therapy for acute myeloid leukemia.

DESIGN AND METHODS

Data were analyzed from a randomized Phase III trial of remission maintenance immunotherapy with histamine dihydrochloride plus low-dose interleukin-2 versus no treatment in adults with acute myeloid leukemia. A two-stage surrogate validation model was applied in which correlations between Kaplan-Meier estimates of leukemia-free survival and overall survival, and between log hazard ratios reflecting treatment effects were analyzed. Country of patient enrollment was the unit of analysis.

RESULTS

Kaplan-Meier estimates of overall survival at 36, 48, and 60 months and leukemia-free survival at 24 months were reasonably correlated (R(2) ranging from 0.44 to 0.84) both for the overall (n=320) and first complete remission (n=261) populations. The effects of histamine dihydrochloride/interleukin-2 on log hazard ratios for leukemia-free survival and overall survival were well correlated (R(2)=0.88-0.93).

CONCLUSIONS

The significant correlations between overall survival and the surrogate end point (leukemia-free survival) and between the effect of histamine dihydrochloride/interleukin-2 on leukemia-free survival and overall survival satisfy the two-stage surrogate validation model.

Progression-free survival and time to progression as surrogate markers of overall survival in patients with advanced gastric cancer: analysis of 36 randomized trials

Progression-free survival (PFS) and time to progression (TTP) have been reported to correlate with overall survival (OS) in several types of cancers. To our knowledge, however, their use in the evaluation of new agents for AGC has not been investigated. We evaluated the potential of PFS and TTP to act as surrogates of OS in clinical trial settings. Randomized trials of systemic chemotherapy for advanced gastric cancer were identified by comprehensive electronic and manual search. Correlations between PFS/TTP and OS were evaluated. Thirty-six trials with a total of 83 treatment arms and 10,484 patients were selected for analysis. The nonparametric Spearman rank correlation coefficient (ρ) between median PFS/TTP and OS was 0.70 (95% CI, 0.59 to 0.82) and the correlation coefficient between hazard ratios in PFS/TTP and OS was 0.80 (95% CI, 0.68 to 0.92). Correlation tended to be higher in trials reporting PFS (ρ = 0.85; 0.72-0.97) than in those reporting TTP (ρ = 0.60; 0.24-0.97), trials in Non-Asian countries (ρ = 0.80; 0.61-0.99) than Asia (ρ = 0.67; 0.39-0.94), trials in patients with measurable lesions only (ρ = 0.91; 0.77-1.00) than in those including non-measurable lesions (ρ = 0.71; 0.50-0.93), albeit that none of these differences was significant. Our results indicate that improvements in PFS/TTP in advanced gastric cancer strongly correlate with improvements in OS. Further research is needed to clarify the surrogacy of PFS/TTP for OS or the role of PFS as the true end point in future randomized clinical trials of chemotherapy for AGC.

Identification of potential surrogate end points in randomized clinical trials of aggressive and indolent non-Hodgkin's lymphoma: correlation of complete response, time-to-event and overall survival end points

BACKGROUND

The correlation between efficacy end points in randomized controlled trials (RCTs) of systemic therapy for non-Hodgkin's lymphoma (NHL) was investigated to identify an appropriate surrogate end point for overall survival (OS).

METHODS

RCTs of previously untreated NHL published from 1990 to 2009 were identified. Associations between absolute differences in efficacy end points were determined using nonparametric Spearman's rank correlation coefficients (r(s)).

RESULTS

Thirty-eight RCTs representing 85 treatment arms for aggressive NHL and 20 RCTs representing 42 arms for indolent NHL were included. For aggressive NHL, differences in 3-year progression-free survival (PFS)/event-free survival (EFS) were high correlated with differences in 5-year OS {r(s) of 0.90 [95% confidence interval (CI) 0.73-0.96]} and linear regression determined that a 10% improvement in 3-year EFS or PFS would predict for a 7% ± 1% improvement in 5-year OS. For indolent histology disease, differences in complete response were strongly correlated with differences in 3-year EFS [r(s) 0.86 (95% CI 0.35-0.97)], but there was no correlation between 3-year time-to-event end points and 5-year OS.

CONCLUSIONS

Improvements in 3-year EFS/PFS are highly correlated with improvements in 5-year OS in aggressive NHL and should be explored as a candidate surrogate end point. Definition of these relationships may inform future clinical trial design and interpretation of interim trial data.