Impact of Renin-Angiotensin System Inhibitors on Response to PD1/L1 Inhibitors in Patients With Metastatic Renal Cell Carcinoma.

Background: The renin-angiotensin-aldosterone system (RAAS), traditionally associated with blood pressure and fluid regulation, also plays a role in tumorigenesis. Renin-angiotensin-aldosterone system inhibitors (RAASI), including angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARBs), have been shown to improve outcomes in various malignant neoplasms. In metastatic urothelial cancer, the use of RAASI have been associated with higher rates of tumor regression in patients receiving immunotherapy (IO) with PD1/L1 inhibitors. This is thought to be due to RAASI-induced downregulation of TGF-beta, for which increased expression is a known mechanism of PD1/L1 inhibitor resistance. We hypothesized that concurrent RAASI in patients with mRCC receiving IO is associated with increased tumor regression.

Methods: We conducted a retrospective analysis of patients with mRCC receiving IO as a first- or second-line therapy from 2016-2023 at the University of Virginia. A logistic regression model was used to evaluate the impact of concurrent RAASI on tumor regression. The primary endpoint was any regression of tumor on imaging.

Results: Data were available for 128 patients with mRCC who received IO as a first- (n = 91, 71.0%) or second- (n = 37, 28.9%) line treatment. Patients who received RAASI during IO were more likely to have tumor regression compared to patients who were not on concurrent RAASI (OR 3.84 [95% CI 1.81-8.47, P =< .001). This held true regardless if patients received IO as a first-line (OR 2.83 [95% CI 1.2-6.94], P = .0173) or second-line (OR 9.5 [95% CI 1.89-73.1], P = .005) treatment.

Conclusions: Our hypothesis generating study suggests that in our mRCC population, concurrent use of RAASI in patients receiving IO was associated with a significantly increased likelihood of tumor regression. These findings highlight the potential therapeutic advantage of RAASI in combination with IO for mRCC patients. Further exploration of this association is warranted in prospective studies to improve treatment outcomes for this patient population.