2387P - Avelumab first-line maintenance (1LM) for locally advanced or metastatic urothelial carcinoma (la/mUC): Treatment (tx) patterns and real-world (rw) outcomes in the US

Background

Avelumab 1LM was approved in the US in June 2020 for patients (pts) with la/mUC without disease progression after 1L platinum-based chemotherapy (PBC). This study describes rw outcomes in pts with la/mUC who received avelumab 1LM.

Methods

Pts with la/mUC diagnosed between Jan 2016 and Mar 2023 were identified in the Tempus database. Pts who completed 1L PBC after avelumab’s UC approval were considered eligible for 1LM. 1LM was differentiated from second-line (2L) tx based on recorded clinical intent or algorithmically based on initiation of immuno-oncology tx within 180 d of 1L PBC completion without recorded disease progression. Rw overall survival (rwOS), progression-free survival (rwPFS), time on treatment (TOT), and time to next treatment were estimated using Kaplan-Meier methods.

Results

Of 3,299 pts, 59% (1,939) received 1L systemic tx. Median age at diagnosis was 70 y, 74% were male, 85% were White, 88% had transitional cell carcinoma, and 48% had a smoking history. For the 50.2% (974/1,939) of pts who completed 1L tx, PBC was the most common 1L tx (66% [644/974]). Median follow-up (f/u) from 1L PBC start was 10.2 mo; median rwOS was 13.6 mo. 89% (574/644) of pts had no evidence of disease progression after completion of 1L PBC; of these, 38% (219/574) had a recorded 1LM tx, with 62% (135/219) receiving avelumab. These pts had a median f/u from 1LM start of 8.9 mo. RwOS landmark analysis from 1LM start showed that 80% of avelumab 1LM pts were still alive at 6 mo and 63% were alive at 12 mo. Median rwPFS from 1LM start was 6.4 mo; median TOT was 3.85 mo. After 1LM avelumab, 35% (47/135) of pts received 2L tx. 70% (33/47) of those received enfortumab vedotin (EV), with a median rwOS from 2L start of 11.6 mo.

Conclusions

Early uptake of avelumab 1LM was observed in pts with la/mUC whose disease had not progressed on 1L PBC. F/u time in avelumab-treated pts was short. Future studies with longer f/u may show increased use and allow further assessment of rwOS. Additionally, rw outcomes are improving with newly available 1L and sequencing options. Our study provides early evidence of the effectiveness of 2L EV following 1L PBC and avelumab 1LM.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

This study was sponsored by Merck (CrossRef Funder ID: 10.13039/100009945), as part of an alliance between Merck and Pfizer.

Disclosure

K. Carson: Financial Interests, Personal, Full or part-time Employment: Tempus Labs, Inc.; Financial Interests, Personal, Ownership Interest: Tempus Labs, Inc. H. Mahmoudpour: Financial Interests, Personal and Institutional, Full or part-time Employment: Merck Healthcare KGaA, Darmstadt, Germany. C. Ike: Financial Interests, Personal, Full or part-time Employment: EMD Serono, Inc., Rockland, MA, USA, an affiliate of Merck KGaA. S. Monzon, S. Fragkogianni, J. Ferrer: Financial Interests, Personal, Full or part-time Employment: Tempus Labs, Inc.; Financial Interests, Personal, Stocks or ownership: Tempus Labs, Inc. M. Kearney: Financial Interests, Personal, Full or part-time Employment: Merck; Financial Interests, Personal, Stocks or ownership: Merck, Novartis, UCB.