Post-study therapy as a source of confounding in survival analysis of first-line studies in patients with advanced non-small-cell lung cancer

The evolving value assessment of cancer therapies: Results from a modified Delphi study

The move toward early detection and treatment of cancer presents challenges for value assessment using traditional endpoints. Current cancer management rarely considers the full economic and societal benefits of therapies. Our study used a modified Delphi process to develop principles for defining and assessing value of cancer therapies that aligns with the current trajectory of oncology research and reflects broader notions of value. 24 experts participated in consensus-building activities across 5 months (16 took part in structured interactions, including a survey, plenary sessions, interviews, and off-line discussions, while 8 participated in interviews). Discussion focused on: 1) which oncology-relevant endpoints should be used for assessing treatments for early-stage cancer and access decisions for early-stage treatments, and 2) the importance of additional value components and how these can be integrated in value assessments. The expert group reached consensus on 4 principles in relation to the first area (consider oncology-relevant endpoints other than overall survival; build evidence for endpoints that provide earlier indication of efficacy; develop evidence for the next generation of predictive measures; use managed entry agreements supported by ongoing evidence collection to address decision-maker evidence needs) and 3 principles in relation to the second (routinely use patient reported outcomes in value assessments; assess broad economic impact of new medicines; consider other value aspects of relevance to patients and society).

Pattern of progression of intrahepatic cholangiocarcinoma: Implications for second-line clinical trials

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is the second most frequent liver cancer. The overall survival of iCCA and other biliary tract cancers (BTC) remains poor. Recently, the ABC-06 trial reported the superiority of FOLFOX vs clinical observation as a second-line treatment. Still, the survival benefit was less than expected. We hypothesized that the pattern of progression of iCCA can drive post-progression survival (PPS), similar to hepatocellular carcinoma.

METHODS

Multicentre retrospective evaluation of consecutive iCCA patients who progressed after frontline systemic treatment with gemcitabine as monotherapy or in combination with platinum. Radiological assessment of progression was evaluated according to RECIST 1.1. The progression pattern was divided according to the presence/absence of new extrahepatic lesions (NEH).

RESULTS

We included 206 patients from 5 centres. The median OS was 14.1 months and its independent predictors (hazard ratio [HR], 95% confidence interval [CI]) were previous surgery 0.699 [0.509-0.961], performance status >2.445 [1.788-3.344], permanent first-line discontinuation 16.072 [5.102-50.633], registration of ascites 2.226 [1.448-3.420] or bilirubin >3 mg/dl 3.004 [1.935-4.664] during the follow-up, and disease progression 2.523 [1.261-5.050]. The appearance of NEH independently predicted OS 2.18 [1.55-3.06] in patients with radiological progression. Amongst 138 patients eligible for second-line treatment, PPS was 16.8 and 5.9 months in cases without and with NEH, respectively (P = .001). Progression owing to NEH lesions was an independent predictor of PPS 1.873 [1.333-2.662], together with performance status, time to progression to the frontline treatment, bilirubin >3 mg/dl and ascites.

CONCLUSIONS

PPS of iCCA is influenced by progression pattern, with important implications for second-line trial design and analysis.

Application of causal inference methods in the analyses of randomised controlled trials: a systematic review

BACKGROUND

Applications of causal inference methods to randomised controlled trial (RCT) data have usually focused on adjusting for compliance with the randomised intervention rather than on using RCT data to address other, non-randomised questions. In this paper we review use of causal inference methods to assess the impact of aspects of patient management other than the randomised intervention in RCTs.

METHODS

We identified papers that used causal inference methodology in RCT data from Medline, Premedline, Embase, Cochrane Library, and Web of Science from 1986 to September 2014, using a forward citation search of five seminal papers, and a keyword search. We did not include studies where inverse probability weighting was used solely to balance baseline characteristics, adjust for loss to follow-up or adjust for non-compliance to randomised treatment. Studies where the exposure could not be assigned were also excluded.

RESULTS

There were 25 papers identified. Nearly half the papers (11/25) estimated the causal effect of concomitant medication on outcome. The remainder were concerned with post-randomisation treatment regimens (sequential treatments, n =5 ), effects of treatment timing (n = 2) and treatment dosing or duration (n = 7). Examples were found in cardiovascular disease (n = 5), HIV (n = 7), cancer (n = 6), mental health (n = 4), paediatrics (n = 2) and transfusion medicine (n = 1). The most common method implemented was a marginal structural model with inverse probability of treatment weighting.

CONCLUSIONS

Examples of studies which exploit RCT data to address non-randomised questions using causal inference methodology remain relatively limited, despite the growth in methodological development and increasing utilisation in observational studies. Further efforts may be needed to promote use of causal methods to address additional clinical questions within RCTs to maximise their value.

Effectiveness and safety of post-induction phase bevacizumab treatment for patients with non-small-cell lung cancer: results from the ARIES observational cohort study

Data from randomized, controlled trials suggest that post-induction phase (IP) treatment with bevacizumab may benefit patients with advanced non-small-cell lung cancer (NSCLC). Real-world clinical practice, however, can involve variable use and patterns of treatment in broader patient populations. To assess the effect of bevacizumab on post-IP overall survival (OS) following IP chemotherapy + bevacizumab, analyses were conducted in patients enrolled in the Avastin(®) Registry--Investigation of Effectiveness and Safety (ARIES) observational cohort study (OCS) who received post-IP bevacizumab. ARIES was a large, prospective OCS of patients who received chemotherapy in combination with bevacizumab for the first-line treatment of NSCLC. This unplanned, post hoc analysis included patients who received chemotherapy and bevacizumab and who did not have progressive disease through the completion of IP treatment. A dichotomous analysis compared outcomes in patients who did and did not receive bevacizumab before a landmark date of day 30 post IP. A cumulative exposure analysis used a time-dependent Cox regression model to assess the effect of cumulative post-IP bevacizumab exposure on post-IP OS. In the dichotomous analysis, the duration of post-IP OS was significantly longer in patients who received post-IP bevacizumab; median post-IP OS was 15.6 vs. 11.3 months, respectively (hazard ratio [HR] = 0.80; 95 % confidence interval 0.71-0.91; P < 0.001). The cumulative exposure analysis observed that each additional cycle of cumulative bevacizumab exposure decreased the HR for post-IP OS by 2.7 %, on average. In conclusion, post-IP bevacizumab exposure was associated with improved post-IP OS in patients with advanced NSCLC who were enrolled in the ARIES OCS.

S-1 plus oxaliplatin versus capecitabine plus oxaliplatin for the first-line treatment of patients with metastatic colorectal cancer: updated results from a phase 3 trial

Background

We report updated progression-free survival (PFS) and overall survival (OS) data from a trial that compared capecitabine plus oxaliplatin (CapeOX) versus S-1 plus oxaliplatin (SOX) for the first-line treatment of metastatic colorectal cancer.

Methods

This trial was a randomized, two-armed, non-inferiority phase 3 comparison of CapeOX (capecitabine 1000 mg/m2 twice daily on days 1–14 and oxaliplatin 130 mg/m2 on day 1) versus SOX (S-1 40 mg/m2 twice daily on days 1–14 and oxaliplatin 130 mg/m2 on day 1). The primary end point was to show non-inferiority of SOX relative to CapeOX in terms of PFS. Thus, a follow-up exploratory analysis of PFS and OS was performed.

Results

The intention to treat (ITT) population was comprised of 340 patients (SOX arm: 168 and CapeOX arm: 172). The updated median PFS was 7.1 months (95% CI 6.4-8.0) in the SOX group and 6.3 months (95% CI 4.9-6.7) in the CapeOX group (hazard ratio [HR], 0.83 [0.66-1.04], p = .10). The median OS was 19.0 months (95% CI 15.3-23.0) in the SOX group and 18.4 months (95% CI 14.1-20.7) in the CapeOX group (HR, 0.86 [0.68-1.08], p = .19). Subgroup analyses according to principal demographic factors such as sex, age, ECOG (Eastern Cooperative Oncology Group) performance status, primary tumor location, measurability, previous adjuvant therapy, number of metastatic organs, and liver metastases showed no interaction between any of these characteristics and the treatment.

Conclusions

Updated survival analysis shows that SOX is similar to CapeOX, confirming the initial PFS analysis. Therefore, the SOX regimen could be an alternative first-line doublet chemotherapy strategy for patients with metastatic colorectal cancer.

Trial registration

NCT00677443 and May 12 2008

Is overall survival still the primary endpoint in maintenance non-small cell lung cancer studies? An analysis of phase III randomised trials

BACKGROUND

In advanced non-small cell lung cancer (NSCLC), the increasing number of active compounds available in second line settings makes overall survival (OS) with maintenance treatment a not frequently observed endpoint. A literature review was conducted to examine whether post-progression survival (PPS) correlates with OS in maintenance trials.

MATERIALS AND METHODS

PPS was defined as median OS - median PFS. The authors used the coefficient of correlation (r) to assess the correlation between them. They also evaluated the surrogacy of PFS and OS.

RESULTS

Ten trials with 11 arms were identified. Overall, a stronger correlation was observed between OS and PPS [Spearman rank correlation coefficient (r) =0.75] than OS and PFS time (r=0.37). The correlation of differences in median PFS (ΔPFS) and median OS (ΔOS) is 0.64 (P=0.0326). The slope of the regression line is 0.76, indicating that a maintenance therapy producing a one-month gain in PFS will yield an estimated three weeks prolongation in OS.

CONCLUSIONS

PPS is strongly associated with OS because of intensive post-study further lines of treatment. However, improvements in PFS are moderately associated with improvements in OS. Hence, in this setting, PFS is a possible surrogate for OS.