Purpose: To assess the role of pathologic complete response (pCR) after neoadjuvant therapy as surrogate end point of disease-free survival (DFS) and overall survival (OS) in patients with breast cancer, we performed a trial-based meta-regression of randomized studies comparing different neoadjuvant systemic treatments. Methods: The systematic literature search included electronic databases and proceedings of oncologic meetings. Endocrine therapy trials were excluded. Treatment effects on DFS and OS were expressed as hazard ratios (HRs), and treatment effects on pCR were expressed as odds ratios (ORs). A weighted regression analysis was performed on log-transformed treatment effect estimates to test the association between treatment effects on the surrogate outcome and treatment effects on the clinical outcome. Results: Twenty-nine trials, 59 arms, and 30 comparisons, for a total of 14,641 patients, were included in the analysis. Using the complete set of data, the regression of either the log(HR) for DFS or the log(HR) for OS on the log(OR) for pCR demonstrated only weak associations (R² = 0.08; 95% CI, 0 to 0.47; and R² = 0.09; 95% CI, 0.01 to 0.41, respectively). Better associations were found in an exploratory analysis assessing a subset of trials comparing intensified/dose-dense chemotherapy versus standard-dose regimens (DFS: R² = 0.79; 95% CI, 0.26 to 0.95; P = .003; and OS: R² = 0.57; 95% CI, 0.19 to 0.93; P = .03). Conclusion: This meta-regression analysis of 29 heterogeneous neoadjuvant trials does not support the use of pCR as a surrogate end point for DFS and OS in patients with breast cancer. However, pCR may potentially meet the criteria of surrogacy with specific systemic therapies.

We assessed the activity and toxicity of the XELBEVOCT regimen in patients with metastatic well-to-moderately differentiated neuroendocrine neoplasms (WMD-NEN). Ancillary studies evaluated hypertension, proteinuria, and vascular endothelial growth factor (VEGF) polymorphisms in predicting progression-free survival (PFS) and the predictive role of serum vitamin D in progression-free survival and proteinuria onset. This prospective phase 2 study included 45 patients with WMD-NEN arising from various primary sites. The treatment regimen was octreotide long-acting release (LAR), 20 mg monthly, metronomic capecitabine, 2000 mg/daily, and intravenous bevacizumab, 5 mg/kg every 2 weeks, without interruption for 9 months. Bevacizumab was continued until disease progression. Partial response was obtained in 8 patients (17.8%, 95% confidence interval [CI], 6.4%-28.2%); tumor response was more frequent in pancreatic than in non-pancreatic malignancies. The median PFS was 14.9 months; median overall survival was not attained. Biochemical and symptomatic responses were observed in 52.9% and 82.3% of cases, respectively. The treatment was well tolerated. Grade 3 toxicities included hand and foot syndrome (11.1%), proteinuria (4.4%), and renal toxicity (2.2%). Proteinuria (all grades) was correlated with longer PFS (p = 0.017). There was an inverse relationship between proteinuria and vitamin D levels. VEGF polymorphisms were not associated with patient outcome. The XELBEVOCT regimen is active and well tolerated in patients with metastatic WMD-NEN. Proteinuria correlated with hypovitaminosis D status and was the best predictive factor of treatment efficacy. Trial registration number NCT01203306 .

Immune-related adverse events (irAEs) are frequently reported during immune checkpoint inhibitor (ICI) therapy and are associated with long-term outcomes. It is unknown if the irAE occurrence is a valid surrogate of ICIs' efficacy. We identified articles reporting the results of randomized trials of experimental ICI therapy in solid tumors with a systematic search. The control arms could be placebo, cytotoxic/targeted therapy, or ICI therapy. We extracted the hazard ratios for overall survival (OS) with the number of OS events per arm and the number and percentages of overall and specific irAEs of grade 1-2 and grade 3-4 per arm. We estimated the treatment effect on the potential surrogate outcome with the odds ratio of the irAE rate between the experimental and the control arm. The statistical analysis consisted of weighted linear regression on a logarithmic scale between treatment effects on irAE rate and treatment effects on OS. Sixty-two randomized trials were included for a total of 79 contrasts and 42 247 patients. The analyses found no significant association between the treatment effects for overall grade 1-2 or grade 3-4 irAE rates or specific (skin, gastrointestinal, endocrine) irAE rates. In the non-small-cell lung cancer (NSCLC) trial subset, we observed a negative association between treatment effects on overall grade 1-2 irAEs and treatment effects on OS in studies with patients selected for programmed death-ligand 1 expression (R² = 0.55; 95% confidence interval 0.20-0.95; R = -0.69). In the melanoma trial subset, a negative association was shown between treatment effects on gastrointestinal grade 3-4 irAEs and treatment effects on OS in trials without an ICI-based control arm (R² = 0.77; 95% confidence interval 0.24-0.99; R = -0.89). We found low-strength correlations between the ICI therapy effects on overall or specific irAE rates and the treatment effects on OS in several cancer types.