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Published on: February 25, 2020
Completion Rate and Positive Results Reporting Among Immunotherapy Trials in Breast Cancer, 2004-2023
Marco Mariani1,2, Giulia Viale1,2, Barbara Galbardi2
1Università Vita-Salute San Raffaele, Milan, Italy.
Importance:
Clinical trials are the path to test and introduce new therapies in the clinic. Trials that are unable to produce results represent inefficiency in the system and may also undermine patient confidence in the new drug development process.
Objectives:
To survey the immunotherapy clinical trial landscape of breast cancer between January 2004 and April 2023 and examine what fraction of trials with primary completion date up to November 30, 2022, failed to report outcome, assessing the proportion of trials that yielded positive results and describing trial features associated with these 2 outcomes.
Design, Setting, And Participants:
This cross-sectional study included breast cancer immunotherapy trials identified in ClinicalTrials.gov. Trial details and results were retrieved in December 2023. Google Scholar, PubMed, and LARVOL CLIN websites were also searched for reports.
Main Outcomes And Measures:
Trial outcome reported as abstract or manuscript. Reported trials were categorized as positive (ie, met its end point) or negative. Association between reporting and trial features were tested using Fisher exact test.
Results:
A total of 331 immuno-oncology trials were initiated in breast cancer by April 2023; 242 trials were phase II, 47 were phase I, and 42 phase III. By setting, 212 studies (64.0%) were conducted in metastatic, 94 (28.4%) in neoadjuvant, and 25 (7.6%) in adjuvant settings. Among phase II and III trials, 168 (59.2%) were nonrandomized. One hundred twenty trials had primary completion dates up to November 30, 2022, of which 30 (25.0%; enrolling a combined 2428 patients) failed to report their outcomes; 7 phase I trials (31.8%), 21 phase II trials (23.6%), and 2 phase III trials (22.2%) were unreported. Single-center studies were significantly more likely to be unreported than multicenter studies (19 of 54 [35.2%] vs 9 of 60 [15.0%]; P = .02). Of the 90 reported trials, 47 (52.2%) and 43 (47.8%) were positive and negative, respectively. Seventeen of 19 (89.5%) of the reported randomized trials (accruing a total of 4189 patients) were negative.
Conclusions And Relevance:
In this cross-sectional study of immunotherapy breast cancer trials, the large number of trials yielded modest clinical impact. Single-center trials commonly failed to report their outcomes and many phase II studies have not translated into corresponding successful phase III trials.
Insights
Many breast cancer immunotherapy trials fail to report outcomes, especially single-center studies. A significant portion of phase II trials did not lead to successful phase III trials, limiting clinical impact.
Area of Science:
- Oncology
- Clinical Trials
- Immunotherapy
Background:
- Clinical trials are crucial for developing new therapies, but reporting failures can hinder progress and patient trust.
- Assessing the outcomes of breast cancer immunotherapy trials is vital for understanding their real-world impact.
Purpose of the Study:
- To analyze the landscape of breast cancer immunotherapy trials from 2004 to 2023.
- To determine the proportion of trials that failed to report outcomes and identify associated trial features.
- To assess the success rate of reported trials and the translation from phase II to phase III studies.
Main Methods:
- A cross-sectional study of breast cancer immunotherapy trials registered in ClinicalTrials.gov.
- Data retrieval from ClinicalTrials.gov, supplemented by searches on Google Scholar, PubMed, and LARVOL CLIN.
- Statistical analysis using Fisher exact test to identify associations between trial features and reporting outcomes.
Main Results:
- Out of 331 initiated trials, 120 had completion dates by November 2022, with 30 (25%) failing to report outcomes.
- Single-center studies were significantly more likely to be unreported (35.2%) compared to multicenter studies (15.0%).
- Of 90 reported trials, 52.2% were positive and 47.8% were negative. Notably, 89.5% of reported randomized trials were negative.
Conclusions:
- The high volume of breast cancer immunotherapy trials has yielded a modest clinical impact.
- A substantial number of single-center trials do not report outcomes, indicating a need for improved reporting practices.
- Many phase II studies have not successfully translated into phase III trials, suggesting a gap in the drug development pipeline.
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