Efficacy of GV1001 with gemcitabine/capecitabine in previously untreated patients with advanced pancreatic ductal adenocarcinoma having high serum eotaxin levels (KG4/2015): an open-label, randomised, Phase 3 trial

BACKGROUND

The TeloVac study indicated GV1001 did not improve the survival of advanced pancreatic ductal adenocarcinoma (PDAC). However, the cytokine examinations suggested that high serum eotaxin levels may predict responses to GV1001. This Phase III trial assessed the efficacy of GV1001 with gemcitabine/capecitabine for eotaxin-high patients with untreated advanced PDAC.

METHODS

Patients recruited from 16 hospitals received gemcitabine (1000 mg/m2, D 1, 8, and 15)/capecitabine (830 mg/m2 BID for 21 days) per month either with (GV1001 group) or without (control group) GV1001 (0.56 mg; D 1, 3, and 5, once on week 2-4, 6, then monthly thereafter) at random in a 1:1 ratio. The primary endpoint was overall survival (OS) and secondary end points included time to progression (TTP), objective response rate, and safety.

RESULTS

Total 148 patients were randomly assigned to the GV1001 (n = 75) and control groups (n = 73). The GV1001 group showed improved median OS (11.3 vs. 7.5 months, P = 0.021) and TTP (7.3 vs. 4.5 months, P = 0.021) compared to the control group. Grade >3 adverse events were reported in 77.3% and 73.1% in the GV1001 and control groups (P = 0.562), respectively.

CONCLUSIONS

GV1001 plus gemcitabine/capecitabine improved OS and TTP compared to gemcitabine/capecitabine alone in eotaxin-high patients with advanced PDAC.

CLINICAL TRIAL REGISTRATION

NCT02854072.

Bias and Type I error Control in Correcting Treatment Effect for Treatment Switching Using Marginal Structural Models in Phase III Oncology Trials

This research focuses on the bias and type I error control issues when the marginal structural models (MSMs) are applied to evaluate the causal survival benefits of active intervention versus control in randomized clinical trials (RCTs) with treatment switching after disease progression. When MSMs are applied in the RCT setting, the question of interest, model specifications, strategies for type I error control, bias reduction, etc. differ somewhat from those for observational studies. This manuscript discusses the approaches used to accommodate these differences. Through Monte Carlo simulations and a case study, our research demonstrates that, with sufficient attention paid to issues applicable to RCTs in particular, MSMs may perform better than the inverse probability of censoring weighting (IPCW) method in analyzing the survival endpoint in RCTs with treatment switching because more information is used by the MSM.

Estimation of Overall Survival with Subsequent Treatment Effect by Applying Inverse Probability of Censoring Weighting in the LATITUDE Study

Background

In the LATITUDE study (ClinicalTrials.gov, NCT01715285), compared with placebos, abiraterone acetate plus prednisone (AAP) with androgen deprivation therapy (ADT) provided significant overall survival (OS) benefit in high-risk metastatic castration-sensitive prostate cancer (mCSPC) patients. It is controversial whether survival benefits would remain if all patients in the placebo group subsequently received life-extending therapies.

Objective

To estimate treatment effect in the case of all patients in the placebo group receiving life-extending subsequent therapies.

Design, setting, and participants

A post hoc analysis of LATITUDE final-analysis data was carried out (setting and participants have been reported previously).

Intervention

AAP or placebos plus ADT.

Outcome measurements and statistical analysis

We applied the inverse probability of censoring weighting (IPCW) method to represent the situation in which all patients in the placebo group would have received life-extending subsequent therapies. The OS hazard ratio (HR) of AAP versus placebos and associated 95% confidence interval (CI) were estimated using a Cox proportional hazards model.

Results and limitations

Of the 581 eligible patients in the placebo group, 237 (40.8%) did not receive life-extending subsequent therapies. From the unadjusted intention-to-treat analysis, the HR for OS for AAP versus placebos was 0.661 (95% CI 0.564–0.775). Using IPCW to adjust for patients in the placebo group without life-extending subsequent therapies, the HR was 0.732 (95% CI 0.604–0.887). A limitation is a lack of proof that the Cox proportional hazards model for the absence of life-extending subsequent therapy is correctly specified for the IPCW method.

Conclusions

Treatment with AAP exerts OS benefit over placebos in high-risk mCSPC patients, regardless of whether life-extending subsequent therapy is given.

Patient summary

In a previous study, high-risk metastatic castration-sensitive prostate cancer patients who received abiraterone acetate plus prednisone (AAP) with androgen deprivation therapy generally survived longer than those given placebos. The benefit of adding AAP continues regardless of whether life-extending subsequent therapy is given.

Prescription opioid treatment for non-cancer pain and initiation of injection drug use: large retrospective cohort study

OBJECTIVE

To assess the association between long term prescription opioid treatment medically dispensed for non-cancer pain and the initiation of injection drug use (IDU) among individuals without a history of substance use.

DESIGN

Retrospective cohort study.

SETTING

Large administrative data source (containing information for about 1.7 million individuals tested for hepatitis C virus or HIV in British Columbia, Canada) with linkage to administrative health databases, including dispensations from community pharmacies.

PARTICIPANTS

Individuals age 11-65 years and without a history of substance use (except alcohol) at baseline.

MAIN OUTCOME MEASURES

Episodes of prescription opioid use for non-cancer pain were identified based on drugs dispensed between 2000 and 2015. Episodes were classified by the increasing length and intensity of opioid use (acute (lasting <90 episode days), episodic (lasting ≥90 episode days; with <90 days' drug supply and/or <50% episode intensity), and chronic (lasting ≥90 episode days; with ≥90 days' drug supply and ≥50% episode intensity)). People with a chronic episode were matched 1:1:1:1 on socioeconomic variables to those with episodic or acute episodes and to those who were opioid naive. IDU initiation was identified by a validated administrative algorithm with high specificity. Cox models weighted by inverse probability of treatment weights assessed the association between opioid use category (chronic, episodic, acute, opioid naive) and IDU initiation.

RESULTS

59 804 participants (14 951 people from each opioid use category) were included in the matched cohort, and followed for a median of 5.8 years. 1149 participants initiated IDU. Cumulative probability of IDU initiation at five years was highest for participants with chronic opioid use (4.0%), followed by those with episodic use (1.3%) and acute use (0.7%), and those who were opioid naive (0.4%). In the inverse probability of treatment weighted Cox model, risk of IDU initiation was 8.4 times higher for those with chronic opioid use versus those who were opioid naive (95% confidence interval 6.4 to 10.9). In a sensitivity analysis limited to individuals with a history of chronic pain, cumulative risk for those with chronic use (3.4% within five years) was lower than the primary results, but the relative risk was not (hazard ratio 9.7 (95% confidence interval 6.5 to 14.5)). IDU initiation was more frequent at higher opioid doses and younger ages.

CONCLUSIONS

The rate of IDU initiation among individuals who received chronic prescription opioid treatment for non-cancer pain was infrequent overall (3-4% within five years) but about eight times higher than among opioid naive individuals. These findings could have implications for strategies to prevent IDU initiation, but should not be used as a reason to support involuntary tapering or discontinuation of long term prescription opioid treatment.

Critical review of oncology clinical trial design under non-proportional hazards

In trials of novel immuno-oncology drugs, the proportional hazards (PH) assumption often does not hold for the primary time-to-event (TTE) efficacy endpoint, likely due to the unique mechanism of action of these drugs. In practice, when it is anticipated that PH may not hold for the TTE endpoint with respect to treatment, the sample size is often still calculated under the PH assumption, and the hazard ratio (HR) from the Cox model is still reported as the primary measure of the treatment effect. Sensitivity analyses of the TTE data using methods that are suitable under non-proportional hazards (non-PH) are commonly pre-planned. In cases where a substantial deviation from the PH assumption is likely, we suggest designing the trial, calculating the sample size and analyzing the data, using a suitable method that accounts for non-PH, after gaining alignment with regulatory authorities. In this comprehensive review article, we describe methods to design a randomized oncology trial, calculate the sample size, analyze the trial data and obtain summary measures of the treatment effect in the presence of non-PH. For each method, we provide examples of its use from the recent oncology trials literature. We also summarize in the Appendix some methods to conduct sensitivity analyses for overall survival (OS) when patients in a randomized trial switch or cross-over to the other treatment arm after disease progression on the initial treatment arm, and obtain an adjusted or weighted HR for OS in the presence of cross-over. This is an example of the treatment itself changing at a specific point in time - this cross-over may lead to a non-PH pattern of diminishing treatment effect.

Induced Bias Due to Crossover Within Randomized Controlled Trials in Surgical Oncology: A Meta-regression Analysis of Minimally Invasive versus Open Surgery for the Treatment of Gastrointestinal Cancer

BACKGROUND

Randomized controlled trials (RCTs) inform clinical practice and have provided the evidence base for introducing minimally invasive surgery (MIS) in surgical oncology. Crossover (unplanned intraoperative conversion of MIS to open surgery) may affect clinical outcomes and the effect size generated from RCTs with homogenization of randomized groups.

OBJECTIVES

Our aims were to identify modifiable factors associated with crossover and assess the impact of crossover on clinical endpoints.

METHODS

A systematic review was performed to identify all RCTs comparing MIS with open surgery for gastrointestinal cancer (1990-2017). Meta-regression analysis was performed to analyze factors associated with crossover and the influence of crossover on endpoints, including 30-day mortality, anastomotic leak rate, and early complications.

RESULTS

Forty RCTs were included, reporting on 11,625 patients from 320 centers. Crossover was shown to affect one in eight patients (mean 12.6%, range 0-45%) and increased with American Society of Anesthesiologists score (β = + 0.895; p = 0.050). Pretrial surgeon volume (β = - 2.344; p = 0.037), composite RCT quality score (β = - 7.594; p = 0.014), and site of tumor (β = - 12.031; p = 0.021, favoring lower over upper gastrointestinal tumors) showed an inverse relationship with crossover. Importantly, multivariate weighted linear regression revealed a statistically significant positive correlation between crossover and 30-day mortality (β = + 0.125; p = 0.033), anastomotic leak rate (β = + 0.550; p = 0.004), and early complications (β = + 1.255; p = 0.001), based on intention-to-treat analysis.

CONCLUSIONS

Crossover in trials was associated with an increase in 30-day mortality, anastomotic leak rate, and early complications within the MIS group based on intention-to-treat analysis, although our analysis did not assess causation. Credentialing surgeons by procedural volume and excluding high comorbidity patients from initial trials are important in minimizing crossover and optimizing RCT validity.

The importance of censoring in competing risks analysis of the subdistribution hazard

BACKGROUND

The analysis of time-to-event data can be complicated by competing risks, which are events that alter the probability of, or completely preclude the occurrence of an event of interest. This is distinct from censoring, which merely prevents us from observing the time at which the event of interest occurs. However, the censoring distribution plays a vital role in the proportional subdistribution hazards model, a commonly used method for regression analysis of time-to-event data in the presence of competing risks.

METHODS

We present the equations that underlie the proportional subdistribution hazards model to highlight the way in which the censoring distribution is included in its estimation via risk set weights. By simulating competing risk data under a proportional subdistribution hazards model with different patterns of censoring, we examine the properties of the estimates from such a model when the censoring distribution is misspecified. We use an example from stem cell transplantation in multiple myeloma to illustrate the issue in real data.

RESULTS

Models that correctly specified the censoring distribution performed better than those that did not, giving lower bias and variance in the estimate of the subdistribution hazard ratio. In particular, when the covariate of interest does not affect the censoring distribution but is used in calculating risk set weights, estimates from the model based on these weights may not reflect the correct likelihood structure and therefore may have suboptimal performance.

CONCLUSIONS

The estimation of the censoring distribution can affect the accuracy and conclusions of a competing risks analysis, so it is important that this issue is considered carefully when analysing time-to-event data in the presence of competing risks.

Nucleotide excision repair and response and survival to chemotherapy in colorectal cancer patients

Several new chemotherapeutic agents have become available for the treatment of colorectal cancer, which has led to increased complexity in treatment planning. Treatment decision making for individual patients could be facilitated if guided by predictive and prognostic markers. As most cytotoxic drugs induce DNA damage, the DNA damage repair pathways hold potential for yielding such biomarkers. Here, we review the current evidence of a possible involvement of the nucleotide excision repair pathway in the efficacy of chemotherapeutic agents used in the treatment of colorectal cancer. Although a large number of studies have been conducted, they are generally of moderate size and heterogeneous in design. Up to date no firm conclusions can be drawn to translate these results into the clinic. We recommend further comprehensive investigations of the nucleotide excision repair pathway in large patient studies that include both discovery and validation cohorts.

Overall Survival Endpoint in Oncology Clinical Trials: Addressing the Effect of Crossover--The Case of Pazopanib in Advanced Renal Cell Carcinoma

OBJECTIVE

To identify the issues of using overall survival (OS) as a primary endpoint in the presence of crossover and the statistical analyses available to adjust for confounded OS due to crossover in oncology clinical trials.

METHODS

An indirect comparison was conducted between pazopanib and sunitinib in advanced renal cell carcinoma. Statistical adjustment methods were used to estimate the true comparative effectiveness of these treatments. Recently, a head-to-head trial comparing pazopanib and sunitinib was completed. This provided the opportunity to compare the OS treatment effect estimated for pazopanib versus sunitinib using indirect comparison and statistical adjustment techniques with that observed in the head-to-head trial.

RESULTS

Using a rank-preserving structural failure time model to adjust for crossover in the pazopanib registration trial, the indirect comparison of pazopanib versus sunitinib resulted in an OS hazard ratio (HR) of 0.97, while an unadjusted analysis resulted in an OS HR of 1.96. The head-to-head trial reported a final OS HR of 0.92 for pazopanib versus sunitinib.

CONCLUSION

This case study supports the need to adjust for confounded OS due to crossover, which enables trials to meet ethical standards and provides decision makers with a more accurate estimate of treatment benefit.

A standardised, generic, validated approach to stratify the magnitude of clinical benefit that can be anticipated from anti-cancer therapies: the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS)

The value of any new therapeutic strategy or treatment is determined by the magnitude of its clinical benefit balanced against its cost. Evidence for clinical benefit from new treatment options is derived from clinical research, in particular phase III randomised trials, which generate unbiased data regarding the efficacy, benefit and safety of new therapeutic approaches. To date, there is no standard tool for grading the magnitude of clinical benefit of cancer therapies, which may range from trivial (median progression-free survival advantage of only a few weeks) to substantial (improved long-term survival). Indeed, in the absence of a standardised approach for grading the magnitude of clinical benefit, conclusions and recommendations derived from studies are often hotly disputed and very modest incremental advances have often been presented, discussed and promoted as major advances or 'breakthroughs'. Recognising the importance of presenting clear and unbiased statements regarding the magnitude of the clinical benefit from new therapeutic approaches derived from high-quality clinical trials, the European Society for Medical Oncology (ESMO) has developed a validated and reproducible tool to assess the magnitude of clinical benefit for cancer medicines, the ESMO Magnitude of Clinical Benefit Scale (ESMO-MCBS). This tool uses a rational, structured and consistent approach to derive a relative ranking of the magnitude of clinically meaningful benefit that can be expected from a new anti-cancer treatment. The ESMO-MCBS is an important first step to the critical public policy issue of value in cancer care, helping to frame the appropriate use of limited public and personal resources to deliver cost-effective and affordable cancer care. The ESMO-MCBS will be a dynamic tool and its criteria will be revised on a regular basis.

Impact of informative censoring on the Kaplan-Meier estimate of progression-free survival in phase II clinical trials

Informative censoring in a progression-free survival (PFS) analysis arises when patients are censored for initiation of an effective anticancer treatment before the protocol-defined progression, and these patients are at a different risk for treatment failure than those who continue on therapy. This may cause bias in the estimated PFS when using the Kaplan-Meier method for analysis. Although there are several articles that discuss this issue from a theoretical perspective or in randomized phase III studies, there are little data to demonstrate the magnitude of the bias on the estimated quantities from a phase II trial. This article describes the issues by using two oncology phase II trials as examples, evaluates the impact of the bias using simulations, and provides recommendations. The two trials were selected because they demonstrate two different reasons for censoring. Simulations show that the magnitude of the bias depends primarily on the proportion of patients who are informatively censored and secondarily on the hazard ratio between the group of patients who remain on study and the group of patients who are informatively censored. Recommendations include using an alternative end point, which includes inadequate response and initial signs of clinical progression as treatment failure, and a competing risk analysis for studies in which competing events preclude or modify the probability of observing the primary event of interest. If informative censoring cannot be avoided, then all patients should be observed until progression, and sensitivity analyses should be used as appropriate.

Neoadjuvant and adjuvant trastuzumab in patients with HER2-positive locally advanced breast cancer (NOAH): follow-up of a randomised controlled superiority trial with a parallel HER2-negative cohort

BACKGROUND

In our randomised, controlled, phase 3 trial NeOAdjuvant Herceptin (NOAH) trial in women with HER2-positive locally advanced or inflammatory breast cancer, neoadjuvant trastuzumab significantly improved pathological complete response rate and event-free survival. We report updated results from our primary analysis to establish the long-term benefit of trastuzumab-containing neoadjuvant therapy.

METHODS

We did this multicentre, open-label, randomised trial in women with HER2-positive locally advanced or inflammatory breast cancer. Participants were randomly assigned (1:1), by computer program with a minimisation technique, to receive neoadjuvant chemotherapy alone or with 1 year of trastuzumab (concurrently with neoadjuvant chemotherapy and continued after surgery). A parallel group with HER2-negative disease was included and received neoadjuvant chemotherapy alone. Our primary endpoint was event-free survival. Analysis was by intention to treat. This study is registered at www.controlled-trials.com, ISRCTN86043495.

FINDINGS

Between June 20, 2002, and Dec 12, 2005, we enrolled 235 patients with HER2-positive disease, of whom 118 received chemotherapy alone and 117 received chemotherapy plus trastuzumab. 99 additional patients with HER2-negative disease were included in the parallel cohort. After a median follow-up of 5.4 years (IQR 3.1-6.8) the event-free-survival benefit from the addition of trastuzumab to chemotherapy was maintained in patients with HER2-positive disease. 5 year event-free survival was 58% (95% CI 48-66) in patients in the trastuzumab group and 43% (34-52) in those in the chemotherapy group; the unadjusted hazard ratio (HR) for event-free survival between the two randomised HER2-positive treatment groups was 0.64 (95% CI 0.44-0.93; two-sided log-rank p=0.016). Event-free survival was strongly associated with pathological complete remission in patients given trastuzumab. Of the 68 patients with a pathological complete response (45 with trastuzumab and 23 with chemotherapy alone), the HR for event-free survival between those with and without trastuzumab was 0.29 (95% CI 0.11-0.78). During follow-up only four cardiovascular adverse events were regarded by the investigator to be drug-related (grade 2 lymphostasis and grade 2 lymphoedema, each in one patient in the trastuzumab group, and grade 2 thrombosis and grade 2 deep vein thrombosis, each in one patient in the chemotherapy-alone group).

INTERPRETATION

These results show a sustained benefit in event-free survival from trastuzumab-containing neoadjuvant therapy followed by adjuvant trastuzumab in patients with locally advanced or inflammatory breast cancer, and provide new insight into the association between pathological complete remission and long-term outcomes in HER2-positive disease.

Preclinical and clinical development of afatinib: a focus on breast cancer and squamous cell carcinoma of the head and neck

ABSTRACT: Aberrant signaling of the ErbB family of receptors plays an integral role in the tumorigenesis of many cancer types, including head and neck squamous cell carcinoma (HNSCC) and breast cancer (BC). Significant research efforts have focused on developing new treatments that target ErbB family members, with the last decade seeing the approval of small-molecule tyrosine kinase inhibitors and monoclonal antibodies that inhibit ErbB signaling. However, treatment resistance is an ever-growing problem and, therefore, new therapies are being investigated to overcome this hurdle. Afatinib is an irreversible ErbB family blocker that has demonstrated potent anti-tumor activity in preclinical models and has displayed clinical efficacy in patients with non-small-cell lung cancer, and activity in HNSCC and BC. Here, the preclinical and clinical development of afatinib in the treatment of non-small-cell lung cancer, HNSCC and BC is described in the context of currently approved agents.

The misguided ethics of crossover trials

Crossover is increasingly favored in trials of cancer therapies; even those that seek to establish the basic efficacy of novel drugs. Crossover is done in part for trial recruitment, but also out of a sense of doing the right thing-offering the investigational agent to more patients. In this paper, we argue that this ethical inclination-that crossover is a preferred trial choice-is misguided. In seeking to sate the desires of participants, we might undermine a trial's ability to answer a meaningful clinical question. When a trial is incapable of answering a question, it becomes unethical. Using a crossover strategy in oncology clinical trials can make trials less ethical, not more.

[Status of clinical trials in oncology--2013 and onwards]

Clinical trials connect basic science with patient care. They form the backbone of evidence-based medicine and clinical guidelines. The unprecedented implementation of new methods in oncology over the past 40 years has only been possible on the basis of multiple well-organized clinical study groups. The continued existence of these study groups in their current multitude is in danger. Far-reaching changes in the legal framework, underfunding, new definitions of patient-related outcome and shifts in the organization of cancer patient care ask for critical reappraisal and new concepts.

Pertuzumab : evolving therapeutic strategies in the management of HER2-overexpressing breast cancer

INTRODUCTION

HER2 overexpression or amplification is present in approximately one-fifth of breast cancers and historically was associated with aggressive disease and poorer prognosis. The introduction of the humanized monoclonal antibody trastuzumab dramatically improved disease-free survival (DFS) and overall survival (OS) in this subgroup. As the majority of patients with metastatic disease ultimately develop resistance to trastuzumab, a need exists for more effective targeted therapies. Pertuzumab is an anti-HER2/neu-targeted therapy in the late stages of clinical development. The combination of pertuzumab, trastuzumab and docetaxel has been found to have an OS benefit in patients with HER2 positive metastatic breast cancer (MBC) when used in the first-line setting. This reflects a new standard of care, and pertuzumab was recently approved for this indication by the Food and Drug Administration (FDA). The efficacy of pertuzumab and trastuzumab in conjunction with chemotherapy is currently being evaluated in the adjuvant setting.

AREAS COVERED

This article provides an overview of preclinical investigations in addition to reviewing pertinent Phase I, Phase II and Phase III clinical trials.

EXPERT OPINION

Pertuzumab, in combination with the humanized monoclonal antibody trastuzumab, and docetaxel is a standard of care for patients with previously untreated metastatic breast cancer based on the CLEOPATRA study showing a survival benefit. There is no increase in cardiac toxicity with the combined HER2-targeted therapy. Future issues will address appropriate sequencing and combination with other anti-HER2-targeted therapies and/or chemotherapy.

Patient reported outcomes of a randomized, placebo-controlled trial of bevacizumab in the front-line treatment of ovarian cancer: a Gynecologic Oncology Group Study

PURPOSE

To analyze quality of life (QOL) in a randomized, placebo-controlled phase III trial concluding that the addition of concurrent and maintenance bevacizumab (Arm 3) to carboplatin and paclitaxel prolongs progression-free survival in front-line treatment of advanced ovarian cancer compared to chemotherapy alone (Arm 1) or chemotherapy with bevacizumab in cycles 2-6 only (Arm 2).

PATIENTS AND METHODS

The Trial Outcome Index of the Functional Assessment of Cancer Therapy-Ovary (FACT-O TOI) was used to assess QOL before cycles 1, 4, 7, 13, and 21; and 6months after completing study therapy. Differences in QOL scores were assessed using a linear mixed model, adjusting for baseline score, and age. The significance level was set at 0.0167 to account for multiple comparisons.

RESULTS

1693 patients were queried. Arm 2 (p<0.001) and Arm 3 (p<0.001) reported lower QOL scores than those in Arm 1. The treatment differences were observed mainly at cycle 4, when the patients receiving bevacizumab (Arm 2 and Arm 3) reported 2.72 points (98.3% CI: 0.88-4.57; effect size=0.18) and 2.96 points (98.3% CI: 1.13-4.78; effect size=0.20) lower QOL respectively, than those in Arm 1. The difference in QOL scores between Arm 1 and Arm 3 remained statistically significant up to cycle 7. The percentage of patients who reported abdominal discomfort dropped over time, without significant differences among study arms.

CONCLUSION

The small QOL difference observed during chemotherapy did not persist during maintenance bevacizumab.

Association between treatment effects on disease progression end points and overall survival in clinical studies of patients with metastatic renal cell carcinoma

BACKGROUND

The relationship between progression-free survival and time to progression (PFS/TTP) and overall survival (OS) has been demonstrated in a variety of solid tumours but not in metastatic renal cell carcinoma (mRCC).

METHODS

A systematic literature search was conducted to identify controlled trials of cytokine or targeted therapies for mRCC reporting information on treatment effects on PFS/TTP and OS for one or more comparison. The associations between treatment effects on PFS/TTP and OS were analysed using linear regression.

RESULTS

Thirty-one studies representing 10943 patients, 75 treatment groups, and 41 comparisons were identified. The correlation coefficient between the negative log of the hazard ratio (HR) for PFS/TTP (-ln HR(PFS/TTP)) vs the negative log of the HR for OS (-ln HR(OS)) was 0.80 (P<0.0001). In linear regression, the coefficient on -ln HR(PFS/TTP) vs -ln HR(OS) was 0.64 (95% confidence interval (CI): 0.470.81; R(2)=0.63), suggesting each 10% relative risk reduction (RRR) for PFS/TTP was associated with a 6% RRR for OS. A 1-month gain in median PFS/TTP was associated with a 1.17-month gain in median OS (95% CI: 0.59,1.76; R(2)=0.28).

CONCLUSION

In trials of treatments for mRCC, treatment effects on PFS/TTP are strongly associated with treatment effects on OS.