Conference Summary: In-Depth Academic Interpretation
Editor’s Note: Dr. Biagio Antonio Maiorano from the Department of Medical Oncology, IRCCS San Raffaele Hospital (Milan, Italy), presented a sub-analysis of the ARON-1 study. This analysis evaluated the real-world incidence of grade 3–4 adverse events (AEs) and their clinical impact on overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) receiving first-line immune checkpoint inhibitor (IO)-based combination therapies.
01 Background: The Gap Between Clinical Trials and Real-World Evidence
IO-based combinations, including IO-IO and IO-TKI regimens, are the current standard of care for first-line mRCC. In pivotal Phase III clinical trials, the reported incidence of grade 3 or higher adverse events (G3-4 AEs) ranged from 48.0% for nivolumab + ipilimumab to 82.4% for IO + TKI combinations. However, clinical trial populations are highly selected and may not fully represent patients in routine clinical practice. The ARON-1 study, a multinational retrospective registry, provides critical real-world evidence (RWE) to address this gap.
02 ARON-1 Study Design and Baseline Characteristics
The ARON-1 study included patients from 17 countries worldwide. This specific analysis included 1,921 mRCC patients treated with IO-based combinations in the first-line setting. • Gender: 75% male. • Median Age: 63 years. • Histology: 85% of patients had clear cell renal cell carcinoma (ccRCC). • Disease Status: Approximately 50% of patients had synchronous metastatic disease.
03 Safety Analysis: Real-World G3-4 AE Incidence Lower Than Clinical Trials
With a median follow-up of 19.1 months, the results showed that approximately one-third (33.3%) of patients in the real-world setting developed a G3-4 AE. This incidence is significantly lower than that reported in pivotal Phase III trials. G3-4 AE Incidence by Regimen: • Nivolumab + Ipilimumab: 29.0% (the lowest among all combinations). • Pembrolizumab + Lenvatinib: 45.0% (the highest among the regimens studied). Common Adverse Events: The most frequent AEs were fatigue, diarrhea, hepatotoxicity, and hypertension. Notably, the incidence of hypertension was significantly higher in the pembrolizumab + lenvatinib group (15%).
04 Risk Factors: Increased Risk in Male and Older Patients
Logistic regression analysis identified specific clinical factors associated with a higher risk of toxicity: • Gender: Male sex was associated with a higher risk of G3-4 AEs. • Age: Advanced age significantly increased the risk of toxicity. • Regimen-Specific Profiles: Fatigue and hypertension were more frequent with pembrolizumab + lenvatinib; diarrhea was more common with pembrolizumab + axitinib or pembrolizumab + lenvatinib; hepatotoxicity was linked to pembrolizumab + axitinib; and hand-foot syndrome was more prevalent with nivolumab + cabozantinib. Hypothyroidism showed a similar incidence across all regimens.
05 Clinical Outcomes: Correlation Between Severe AEs and Improved Survival
Survival analysis revealed a key clinical finding: patients who developed G3-4 AEs tended to have better survival outcomes. • Overall Population Median OS (mOS): Approximately 40 months. • G3-4 AE Group vs. Non-AE Group: mOS was 57.0 months versus 38.9 months, respectively. 6-Month Landmark Analysis: To minimize the guarantee-time bias (where longer treatment duration increases the likelihood of toxicity), a 6-month landmark analysis was performed, confirming the survival advantage: • Landmark OS (Total Population): 59 months. • G3-4 AE Group: mOS reached 63 months. • Non-G3-4 AE Group: mOS was 52 months.
06 Conclusion and Perspectives
Dr. Biagio Antonio Maiorano concluded that the ARON-1 study demonstrates that the real-world safety profile of first-line IO combinations in mRCC is more favorable than that reported in pivotal clinical trials. The findings underscore the importance of considering patient-specific (gender, age) and regimen-specific factors in routine practice. Crucially, the occurrence of severe AEs may serve as a surrogate marker for a more robust immune response and superior survival. As clinicians move along the learning curve for managing immune-mediated toxicities, the ability to balance safety and efficacy has improved since the initial clinical trial era.
