Progression-free survival and one-year milestone survival as surrogates for overall survival in previously treated advanced non-small cell lung cancer

Correlations of response rate and progression-free survival with overall survival in immunotherapy trials for metastatic non-small-cell lung cancer: an FDA pooled analysis

BACKGROUND

Radiographic changes might not fully capture the treatment effects of immune checkpoint inhibitors (ICIs). We aimed to assess correlations of overall response rate and progression-free survival with overall survival in trials of ICIs for metastatic non-small-cell lung cancer (NSCLC).

METHODS

To assess trial-level and patient-level correlations of overall response rate and progression-free survival with overall survival, we conducted a pooled analysis of first-line randomised trials (including patients aged ≥18 years with metastatic squamous and non-squamous NSCLC and an Eastern Cooperative Oncology Group performance status of 0-1) submitted to the US Food and Drug Administration from June 24, 2016, to March 16, 2021. Eligible trials evaluated at least one ICI in the experimental group versus chemotherapy in the control group. At the trial level, we used weighted linear regression to derive coefficients of determination (R2). At the patient level, we used Cox proportional hazards models to compare overall survival between responders versus non-responders per Response Evaluation Criteria in Solid Tumours (version 1.1).

FINDINGS

A total of 13 trials including 9285 patients evaluated ICIs alone or in combination with chemotherapy versus chemotherapy alone. At the trial level, the R2 was 0·61 (95% CI 0·32-0·84) for correlation of overall response rate with overall survival and 0·70 (0·40-0·89) for correlation of progression-free survival with overall survival. Correlations ranged from weak to moderate when evaluating subgroups by PD-L1 expression and were consistent across trials evaluating ICIs alone or in combination with chemotherapy. At the patient level, responders had longer overall survival than non-responders (hazard ratio [HR] 0·28 [95% CI 0·26-0·30]). Among responders, overall survival was longer in patients enrolled in experimental groups than in control groups (HR 0·54 [95% CI 0·48-0·61]).

INTERPRETATION

Correlations of overall response rate and progression-free survival with overall survival were generally moderate in this pooled analysis. The findings support routine analysis of mature overall survival data, where feasible, in first-line randomised trials of ICIs for metastatic NSCLC.

FUNDING

US Food and Drug Administration.

Surrogacy of one-year survival for overall survival in advanced hepatocellular carcinoma

BACKGROUND

The increasing number of sequential treatments complicates the evaluation of overall survival (OS) in clinical trials for hepatocellular carcinoma (HCC), therefore, reliable surrogate endpoints (SEs) are required. This study aimed to evaluate the surrogacy of progression-free survival (PFS) and one-year (1-yr) milestone survival for OS in HCC trials.

METHODS

We systematically searched databases for randomized clinical trials that evaluated systemic treatments for advanced HCC. Individual patient data were reconstructed to calculate the 1-yr survival rate. We adopted a two-stage meta-analytic validation model to evaluate the correlation between SEs and OS, and the correlation between treatment effects on SEs and OS. The hazard ratio (HR) was calculated to assess the treatment effects on PFS and OS, and the 1-yr survival ratio was calculated to evaluate the treatment effects on the 1-yr milestone survival.

RESULTS

Thirty-two HCC trials involving 13,808 patients were included. A weak correlation was detected between the median PFS and median OS (R2 = 0.32), whereas the correlation improved between PFS HR and OS HR (R2 = 0.58). We identified strong correlations between the 1-yr survival rate and median OS and between the 1-yr survival ratio and OS HR (R2 = 0.74 and 0.65, respectively). In subgroup analyses, PFS HR strongly correlated with OS HR in trials relevant to immune checkpoint inhibitors (ICIs). Although the correlation remained weak between PFS and OS even in trials with PFS HR ≤ 0.6, the 1-yr survival rate and 1-yr survival ratio were strong surrogates for median OS and OS HR, respectively (R2 = 0.77 and 0.75).

CONCLUSIONS

One-year milestone survival outperformed PFS as a SE for OS in HCC, indicating the application of 1-yr survival as a secondary endpoint. In particular, PFS HR was a potential SE for OS HR in the ICI trials.

Identification on surrogating overall survival with progression-free survival of first-line immunochemotherapy in advanced esophageal squamous cell carcinoma-an exploration of surrogate endpoint

BACKGROUND

Overall survival (OS) is the gold standard to assess novel therapeutics to treat cancer. However, to identify early efficacy and speed up drug approval, trials have used progression-free survival (PFS) as a surrogate endpoint (SE). Herein, we aimed to examine if PFS could function as an OS surrogate in advanced Esophageal Squamous Cell Carcinoma (ESCC) treated with first-line immunochemotherapy.

METHODS

Two hundred ninety-two advanced ESCC patients treated using inhibitors of PD-1/PD-L1 + chemotherapy or chemotherapy alone were collected. In addition, six phase III randomized clinical trials were eligible for inclusion. Bayesian normal-induced-copula-estimation model in retrospective patient data and regression analysis in the published trial data were used to determine the PFS-OS correlation.

RESULTS

PFS correlated moderately with OS in the retrospective cohort (Kendall's Tau = 0.684, τ = 0.436). In trial-level, treatments effects for PFS correlated weakly with those for OS in intention-to-treat population (R² = 0.436, adj.R² = 0.249, P > 0.05) and in PD-L1-enriched population (R² = 0.072). In arm-level, median PFS also correlated weakly with median OS. Moreover, analysis of the retrospective cohort demonstrated that the annual death risk after progression in the continued immunotherapy group was considerably lower than that in the discontinued group.

CONCLUSION

In trials of anti-PD-1 agents to treat advanced ESCC, the current results provide only weak support for PFS as an OS surrogate; OS cannot be substituted completely by PFS in these cases. The results also suggest that qualified patients with advanced ESCC might benefit from continuous immunotherapy beyond progression to achieve a decreased risk of death.

VEGF single nucleotide polymorphisms predict improved outcome in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy

We aimed to investigate the prognostic role of genetic variants of VEGF in advanced NSCLC patients treated with platinum-based chemotherapy. A total of 196 patients with advanced NSCLC treated with first-line platinum-based chemotherapy were enrolled. We evaluated the relationship between VEGF polymorphisms and efficacy outcomes and chemotherapy toxicity. We found that rs699947, rs833061 and rs1005230 were in full linkage disequilibrium. Patients with CC genotype of rs833061 had a significant longer PFS than TT genotype (CC vs TT, HR = 1.67, 95%CI = 1.01-2.76, P = 0.043). Patients harbouring CC genotype had longer PFS compared with CT genotype (P < 0.001). Moreover, CC genotypes conferred a significantly increased PFS compared to CT and TT genotype in dominant model (CC vs CT + TT, HR = 1.95, 95%CI = 1.23-3.10, P = 0.005). Patients carrying TT genotype of rs833061 had improved both ORR (HR = 0.54, 95%CI = 0.30-0.98, P = 0.041) and DCR (HR = 0.37, 95%CI = 0.20-0.66, P = 0.001) than non-TT patients. Furthermore, no association was found between any rs833061 alleles and adverse events (P = 0.425), but patients carrying rs1570360 AA genotype were more likely to experience grade 3-4 toxicities (P = 0.004) (GG vs AA, HR = 3.16, 95%CI = 1.26-7.94, P = 0.015). In conclusion, the variant homozygote CC of rs833061 exhibited a better prognosis based on association analysis. The present study provides reference for the future study of platinum-based chemotherapy response and toxicity.

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

Background

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

Methods

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

Results

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

Conclusions

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

Progression-free survival assessed per immune-related or conventional response criteria, which is the better surrogate endpoint for overall survival in trials of immune-checkpoint inhibitors in lung cancer: A systematic review and meta-analysis

Progression-free survival (PFS) has been used as a surrogate endpoint for overall survival (OS) in lung cancer trials. The pattern of response to immune-checkpoint inhibitors (ICIs) differs from that to conventional chemotherapy, so immune-related response evaluation criteria were proposed. This study aims at determining which PFS measure, PFS assessed per immune-related response evaluation criteria (iPFS), or conventional criteria (cPFS), is the better surrogate endpoint for OS in trials of ICIs in lung cancer. We selected clinical trials in lung cancer that administered ICIs to at least one arm and reported both median OS and median PFS from PubMed, Embase, and The Cochrane Library. We compared the correlation between treatment effect (hazard ratio) on OS and cPFS or iPFS and the correlation between median OS and median cPFS or iPFS using weighted linear regression at trial level. We analyzed 78 ICI arms (13,438 patients) from 54 studies, including 66 arms with cPFS, seven arms with iPFS, and five arms with both kinds of PFS. We demonstrated an excellent correlation between treatment effect (hazard ratio) on OS and iPFS (RWLS2  = 0.91), while the correlation was moderate for cPFS (RWLS2  = 0.38). Similarly, the correlation between median OS and median iPFS was also strong (RWLS2 ranging from 0.86 to 0.96) across different phases of trials and different types of lung cancer, ICI, and treatment modalities, while it was much weaker for median cPFS (RWLS2 ranging from 0.28 to 0.88). In conclusion, iPFS provides better trial-level surrogacy for OS than cPFS in trials of ICIs in lung cancer.

Hazard ratio of progression-free survival is an excellent predictor of overall survival in phase III randomized controlled trials evaluating the first-line chemotherapy for extensive-disease small-cell lung cancer

Background

Whether hazard ratio (HR) of progression-free survival (HRpfs), odds ratio (OR) of response rate (ORrr), OR of disease control rate (ORdcr), and OR of 1-year overall survival (ORos1y) used for extensive-disease small-cell lung cancer (ED-SCLC) correlate with HR of overall survival (HRos) at a randomized-trial level, especially for a trial that evaluates molecular-targeted therapy (MTT) or immune-checkpoint inhibitor (ICI), is unclear.

Methods

We included an individually randomized controlled trial (RCT) comparing two regimens as the first-line treatment for chemo-naive ED-SCLC, which have been reported in English-language since 2000. A weighted Spearman’s rank correlation coefficient (r) was evaluated.

Results

We finally found 42 eligible articles consisted of 11,478 cases. Estimated r with HRos were as followings: HRpfs (29 trial, 8,573 cases, r=0.87), ORrr (39 trials, 11,030 cases, r=0.47), ORdcr (29 trials, 7,799 cases, r=0.48), and ORos1y (40 trials, 11,250 cases, r=0.69). Phase III subgroup (16 trials, 7,079 cases) yielded an excellent r between HRpfs and HRos of 0.96. ORdcr presented the best correlation with HRos for phase II trial subgroup (r=−0.64); however, this result was mainly calculated from MTT trials. HRpfs may overestimate the efficacy of MMT in a phase II trial. ORrr and ORdcr might undervalue the efficacy of ICI even in a phase III trial.

Conclusions

HRpfs can be a good surrogate of HRos, especially in a phase III trial. Depending on a single outcome in a randomized phase II trial may result in unneeded phase III trial or inappropriate abandonment of the regimen.

Challenges of evaluating immunotherapy efficacy in solid tumors

Immunotherapy is one of the most promising treatments for multiple tumor types. The significant clinical benefits and durable responses of immunotherapy have led to the emergence of various immune-related clinical response patterns that extend beyond those achieved with cytotoxic agents. Various studies investigated the efficacy of immunotherapy, including the effect on tumor size, long-term survival benefits, and the ability to overcome the particularly challenging survival curves tailing phenomenon. The current immune-related methods guidelines, such as immune-related Response Criteria (irRC), immune-related Response Evaluation Criteria in Solid Tumors (irRECIST), immune Response Evaluation Criteria in Solid Tumors (iRECIST), and immune-modified Response Evaluation Criteria in Solid Tumors (imRECIST), could be well-adapted to identify the heterogeneity of responses that appear in patients receiving immunotherapy, such as pseudoprogression (PsPD) and hyperprogressive disease (HPD), and to some extent to overcome the limitation of evaluating the efficacy of immunotherapy on tumor size by imaging. Additionally, a second type of evaluation method was proposed based on survival, which includes milestone analysis and restricted mean survival time. Currently, milestone analysis is a complementary tool to summarize and interpret trial results along with more conventional measures of survival and other less established metrics. A golden standard evaluation method to distinguish the efficacy of immunotherapy may improve the process of imaging and aid survival-based efficacy evaluation in patients with solid tumors.

Endpoint surrogacy in oncological randomized controlled trials with immunotherapies: a systematic review of trial-level and arm-level meta-analyses

Few cancer drugs or their indications achieved survival benefit in subsequent trials during postmarket period after approval based on surrogate endpoints. This causes a concern of using surrogate endpoints instead of overall survival (OS) as the primary endpoint for trial design, implementation and regulation approval. We conducted a systematic review to summarize the findings from published meta-analyses which have evaluated endpoint surrogacy for OS in oncological randomized controlled trials (RCTs) with immunotherapies. After searching articles indexed in PubMed prior to 24 February 2019, we identified a total of 11 meta-analyses for advanced multiple tumors, non-small cell lung cancer (NSCLC), urothelial carcinoma, renal cell carcinoma, melanoma; most (91%; 10/11) focused on immune checkpoint inhibitors. Although the evaluation criteria adopted by these meta-analyses for validating endpoint surrogacy were not consistent (ranging from R² ≥0.60 to R² ≥0.80), the results were consistent. Few studies show an association between OS and progression-free survival (PFS)/objective response rate (ORR) that met the lowest evaluation criteria (R² ≥0.60), based on treatment effects (8%; 2/26 indications) or absolute results from experimental arm (0%; 0/11 indications). However, the association between OS and 1-year survival rate met the lowest criteria based on both the trial-level results (4/4 indications) and the arm-level results (5/5 indications). In lieu of this finding, we are supportive of an alternative endpoint, e.g., 1-year survival rate, rather than the more conventional choices PFS and ORR, as promising surrogate endpoint for OS in immunotherapy RCTs. We encourage further investigation on endpoint surrogacy based on the same or different settings, especially an assessment on survival rate at milestone time (e.g., 1-year), which has been demonstrated valuable for predicting OS in meta-analyses.