Abstract 1901
Background
AEs resulting from placebo administration have not been well studied in oncology. The aim of this study was to describe the incidence of AEs in the placebo arms of target and immunotherapy cancer drugs in all treatment settings, and to analyze their relation with AEs reported in the active arms of included trials.
Methods
Based on PRISMA guidelines, a systematic literature search was performed including phase 3, randomized, double-blind, placebo-controlled trials from 1/1/2000 to 1/5/19. Adjuvant and advanced-stage studies using targeted and immunotherapy were included. Trials involving active anticancer treatment in addition to placebo in the control group were excluded. Random-effects meta-analysis was performed to estimate the incidence of grade 3-4 placebo AEs.
Results
Of 4396 studies screened, 40 trials were eligible (adjuvant n = 14; advanced n = 26) including 10 cancer types and 28,520. Median incidence of any-grade placebo AEs was 90% (IQR 89-91%) in the adjuvant and 89.5% (IQR 72-96%) in the advanced trials. Grade 5 drug-related AEs were reported in 19 pts receiving placebo. 4 trials reported a higher frequency of grade 3-4 AEs in the placebo arm than in the active treatment arm. The overall, random-effects pooled incidence of grade 3-4 placebo AEs was 22% (95% CI, 17-27%; [I2= 95%]) for the adjuvant and 27% (95% CI, 20-35%; [I2= 97%]) for the advanced trials. No statistical differences were observed comparing both settings (Wilcoxon rank-sum test, P = 0.2). Frequency of grade 3-4 placebo AEs was found to be correlated between the treatment and placebo arms in both adjuvant (ρ = 0.5; P = .042) and advanced studies (ρ = 0.6; P = .003).
Conclusions
Placebo administration was associated with a substantial incidence of grade 3-4 placebo AEs in adjuvant and advanced settings. An association between the active treatment and placebo arms was observed in both scenarios. These findings should be taken into consideration by the medical community in the toxicity evaluation criteria of a placebo-controlled clinical trial.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
5107 - Tolerability of PCV in Low Grade Glioma: a Real World Experience
Presenter: Razia Aslam
Session: Poster Display session 1
Resources:
Abstract
6171 - Molecular EGFR/PD-L1 profile of glioblastoma: Hints for therapeutic strategies
Presenter: Wojciech Szopa
Session: Poster Display session 1
Resources:
Abstract
4418 - Role of Intraoperative MRI (iMRI) in neurosurgery, potential imaging tool for maximizing gross total resection (GTR) rate of CNS tumours.
Presenter: Shweta Wadhwa
Session: Poster Display session 1
Resources:
Abstract
4791 - Tumor related impairments of neurocognitive functions in patients with brain metastases
Presenter: Lei Wen
Session: Poster Display session 1
Resources:
Abstract
5372 - Is radiation therapy influencing Alzheimer’s in Brain and Head and Neck Cancers?
Presenter: Anas Saad
Session: Poster Display session 1
Resources:
Abstract
2329 - Mature Treatment Results of 120 Cases of Acoustic Neuroma Treated with Cyberknife at a single institution.
Presenter: Shawn Malone
Session: Poster Display session 1
Resources:
Abstract
3207 - A phase II/III trial of high-dose, intermittent sunitinib in patients with recurrent glioblastoma: the STELLAR study
Presenter: Cyrillo Brahm
Session: Poster Display session 1
Resources:
Abstract
3589 - CNS penetration and Preliminary Efficacy of Sacutizumab Govitecan in Breast Brain Metastasis and Glioblastoma: A Surgical Study
Presenter: Andrew Brenner
Session: Poster Display session 1
Resources:
Abstract
1969 - Wedge resection with omission of lymph node dissection as an optional treatment strategy in octogenarians or older with early stage non-small cell lung cancers
Presenter: Takahiro Mimae
Session: Poster Display session 1
Resources:
Abstract
5116 - Characterization of lung tumorspheres reveals cancer stem-like cells potential targets and prognostic markers in non-small cell lung cancer
Presenter: Alejandro Herreros Pomares
Session: Poster Display session 1
Resources:
Abstract