Ribociclib-Induced Pneumonitis: A Case Report

Concurrent use of Radiotherapy and Ribociclib: Preliminary Results and Review of the Literature

OBJECTIVES

In the recent MONALEESA-2, MONALEESA-3, and MONALEESA-7 clinical trials, the addition of ribociclib, a CDK4/6 inhibitor, to standard endocrine therapy significantly improved progression-free survival (PFS) compared with hormone therapy alone in the treatment of locally advanced or metastatic estrogen receptor-positive (ER) and HER2-negative breast cancer. However, its toxicity raises concerns when administered concomitantly with radiotherapy, leading most radiotherapists and medical oncologists to prefer to discontinue Ribociclib during radiotherapy (RT). Although there are insufficient published data on this combination, our preliminary experience with the first 2 patients treated at Institut Curie suggests promising results when using Ribociclib with Letrozole or Fulvestrant concurrently with palliative radiotherapy in the treatment of metastatic breast cancer. Our study aimed to evaluate the safety of combining Ribociclib with palliative radiotherapy in patients with metastatic breast cancer, providing crucial insights for clinical decision-making.

METHODS

A retrospective analysis was conducted on patients treated for hormone receptor-positive metastatic breast cancer with Ribociclib and concurrent radiotherapy at the Institut Curie (Paris, France) between September 2023 and April 2024. Among 38 patients who received Ribociclib and underwent irradiation, 36 temporarily suspended Ribociclib during radiotherapy, while 2 continued Ribociclib concurrently and were included in the analysis. Palliative radiotherapy was administered using volumetric modulated arc therapy, delivering 20 Gy in 5 fractions to bone metastatic sites. Ribociclib was given at 600 mg/day with hormonotherapy. Follow-up was conducted from the last day of RT until the last medical consultation. Toxicities were graded using CTCAE V5.0.

RESULTS

Two patients received Ribociclib concomitantly with radiotherapy, experiencing pain relief without interruptions in RT. However, Ribociclib treatment was halted in both cases due to grade 3 neutropenia and grade 1 QTc interval prolongation, respectively. One patient had a dose reduction to 400 mg due to neutropenia, with favorable outcomes observed. Both patients continued Ribociclib treatment, with one achieving complete remission and the other partial remission of bone disease. No late toxicities were observed.

CONCLUSION

Despite the need for further investigation, our results suggest safety consistent with pivotal trials, advocating for a prospective cooperative data collection initiative to explore this combined strategy further, potentially revolutionizing metastatic breast cancer management.

Infection associated with CDK4/6 inhibitors: a pharmacovigilance analysis of the FDA adverse event reporting system database

Introduction

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are first-line treatments for hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer. With their increasing clinical use, infection-related adverse events (AEs) associated with CDK4/6 inhibitors have been widely reported in recent years. This study aimed to analyze the occurrence of infections associated with the CDK4/6 inhibitors (palbociclib, ribociclib and abemaciclib) based on the real-world data from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

Methods

Data were extracted from the FAERS database between 2015Q1 and 2022Q3. The clinical characteristics of patients with primary suspected infection-related AEs were analyzed. A disproportionality analysis was performed to investigate the potential association between AEs and CDK4/6 inhibitors. The influencing factors were evaluated using Pearson's chi-square test.

Results

Reports of infection-related AEs associated with ribociclib accounted for 8.58% of the total reports of AEs associated with ribociclib, followed by palbociclib (2.72%) and abemaciclib (1.24%). Ribociclib (67.65%) was associated with more serious outcome events than palbociclib (30%) or abemaciclib (48.08%). The sex and age were not associated with outcome severity. Disproportionality analysis showed that fourteen, sixteen and two infection-related preferred terms were detected for palbociclib, ribociclib and abemaciclib, respectively.

Conclusion

Infection-related AEs were highly associated with three CDK4/6 inhibitors, especially palbociclib and ribociclib, based on the real-world data from the FAERS database. However, further causality assessment is required.

Ribociclib-induced pulmonary infiltrates in a patient with breast cancer

INTRODUCTION

Breast cancer is the most common cancer in women worldwide. One of the treatment choices used in hormone receptor positive and HER2 expression negative metastatic breast cancer is cyclin dependent kinase 4/6 (CDK) inhibitors. There are differences between the effects and adverse events of all CDK4/6 inhibitors. In this report, we describe a 48-year-old female patient with breast cancer who developed pulmonary infiltrates secondary to drug in the second year of follow-up with Ribociclib therapy.

CASE REPORT

The patient who used ribociclib for metastatic breast cancer was admitted to hospital for routine controls. The patient, in the eighth month of ribociclib treatment, had no active complaints. In the patient's imaging, pulmonary infiltrates were detected in the lower lobe of the right lung.

MANAGEMENT AND OUTCOME

The drug was continued in the patient who was asymptomatic and had no infectious signs. Pneumonitis, interstitial lung disease, tuberculosis, COVID-19 and other viral agents were excluded in the patient. A minimal increase in pulmonary infiltrates was observed in the follow-up. However, the patient who does not have any complaints is currently continuing ribociclib at 600 mg/day.

DISCUSSION

The pulmonary infiltrates that developed in the patient increased with continued use of ribociclib, suggesting that this was due to ribociclib. The Naranjo Adverse Drug Reaction Probability Scale also indicates probable relationship.

Clinical features of CDK4/6 inhibitor-related interstitial lung disease in patients with breast cancer: a case series study

BACKGROUND

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are the standard treatment for advanced hormone receptor-positive breast cancer. Although interstitial lung disease is a rare (1-3.3%) but serious adverse event associated with CDK4/6 inhibitors, the incidence of interstitial lung disease in Japanese patients in the real world and the risk factors of interstitial lung disease are not clear.

METHODS

We retrospectively investigated the incidence of interstitial lung disease in 224 patients with advanced breast cancer who received CDK4/6 inhibitors at our hospital between 31 January 2017 and 31 January 2021. The correlation of age (>50 vs ≤50 years), presence or absence of previous history of interstitial lung disease, lung metastasis, smoking history and chest radiation with the development of interstitial lung disease was evaluated.

RESULTS

In total, 177 cases received palbociclib, 39 cases received abemaciclib and 8 cases received both palbociclib and abemaciclib, constituting a palbociclib group (n = 185) and an abemaciclib group (n = 47). At a median observation period of 607 days, 8.0% (18/224) cases (13 definite and 5 probable cases) had interstitial lung disease; 6.5% (12/185) of palbociclib-treated and 13% (6/47) of abemaciclib-treated cases. The median time to interstitial lung disease onset was 178 (range, 14-750) days. There was no significant correlation between the background factors studied and the development of interstitial lung disease.

CONCLUSION

The frequency of CDK4/6 inhibitor-induced interstitial lung disease was higher than that reported in clinical trials. We did not identify any risk factors for the development of interstitial lung disease in this study, and thus, larger studies that include patient predisposition are required.

Interstitial lung disease in patients treated with Cyclin-Dependent Kinase 4/6 inhibitors: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Cyclin-Dependent Kinase (CDK) 4/6 inhibitors have shown significant clinical activity in cancer patients. However, some concerns regarding rare adverse events (AEs) have occurred including interstitial lung disease (ILD)/pneumonitis, for which data are deficient. The aim of this study was to evaluate the overall incidence and risk of ILD/pneumonitis related to CDK4/6 inhibitors in randomized controlled trials (RCTs).

METHODS

Electronic databases and ClinicalTrials.gov were searched from inception to October 1, 2021 for RCTs reporting the occurrence of LD/pneumonitis in cancer patients treated with CDK4/6 inhibitors. Peto odds ratios (Peto ORs) and 95% confidence intervals (CIs) were used to pool the study.

RESULTS

12 RCTs with a total of 16,060 patients were eligible. The overall incidence of all-grade ILD/pneumonitis was 1.6% (131/8407) in the treatment group compared with 0.7% (50/7349) in the control group. CDK4/6 inhibitors significantly increased the risk of all-grade ILD/pneumonitis with a pooled Peto OR of 2.12 (95% CI [1.57, 2.86], P < 0.00001) with no heterogeneity (I² = 0%, χ² P = 0.98). A higher incidence of grade 3 or higher ILD/pneumonitis was also observed in the treatment group (0.2%, 16/7087) compared with the control group (0.05%, 3/6617) with a Peto OR of 3.22 (95% CI [1.28, 8.09], P = 0.01) with no heterogeneity (I² = 0%, χ² P = 0.62). Two grade 5 pneumonitis were reported in the included studies. Subgroup analyses did not show any significant difference.

CONCLUSIONS

The risk of all-grade and grade 3 or higher ILD/pneumonitis was higher in patients treated with CDK4/6 inhibitors compared to controls. The awareness for these rare AEs in the application of CDK4/6 inhibitors should be enhanced. Further studies are required to validate the mechanisms and the risk factors of ILD/pneumonitis with CDK4/6 inhibitors.

Ribociclib-associated organising pneumonia

A 63-year-old woman with grade 2 infiltrating left breast carcinoma who was started on ribociclib complained of exertional dyspnoea along with dry cough. There were bilateral interscapular crackles and chest X-ray evidence of bilateral mid and lower zone non-homogeneous opacity. The patient's pulmonary function test (PFT) showed moderate restrictions and desaturation. CT was suggestive of organising pneumonia and drug administration was stopped. The patient was treated with steroids in tapering doses, which led to improvements. The drug was restarted with the probability of other aetiologies for interstetial lung disease (ILD). It was also considered the superior efficacy of ribociclib in managing breast cancer. But due to evidence indicating the reappearance of organising pneumonia following drug administration, it was again stopped, and steroid use was restarted for treatment. The patient showed improvements in subsequent follow-ups.