Adverse Events in a Randomized Trial Comparing Radiotherapy with or without Olaparib for Inflammatory Breast Cancer
Reshma Jagsi1, Allison Meisner2, Pavani Chalasani3
1Emory University, Atlanta, GA, USA; University of Michigan, Ann Arbor, MI, USA.
Summary
Concurrent olaparib with breast radiotherapy increased radiation dermatitis and other adverse events. Caution is advised when using olaparib with radiotherapy outside clinical trials.
Area of Science:
- Oncology
- Radiotherapy
- Pharmacology
Background:
- Conflicting reports exist on PARP inhibitors' tolerability with breast radiotherapy.
- Analysis of adverse events from a national cooperative group trial is motivated by these reports.
Purpose of the Study:
- To analyze and compare adverse events in patients receiving concurrent radiotherapy and olaparib versus radiotherapy alone.
- To assess the safety profile of olaparib when administered concurrently with breast radiotherapy.
Main Methods:
- A Phase 2 NCI-cooperative group trial enrolled 146 patients with inflammatory, non-metastatic breast cancer.
- Patients received either standard radiotherapy or radiotherapy plus olaparib (25 mg twice daily).
- Adverse events were assessed weekly using CTCAE v5.0 and categorized by treatment relationship.
Main Results:
- Grade 3 radiation dermatitis occurred in 24.7% of the olaparib group vs. 5.5% of the control group (p=0.003).
- All acute chest-region adverse events were significantly higher in the olaparib arm (24.7% vs. 6.8%, p=0.006).
- Gastrointestinal events and laboratory abnormalities were more frequent in the olaparib group.
Conclusions:
- Concurrent administration of olaparib and radiotherapy is associated with increased adverse events.
- Caution is recommended when considering olaparib with radiotherapy outside of investigational settings.