Time to real-world progression (TTrwP) among patients (pts) with relapsed/refractory (R/R) testicular germ cell tumors (GCT) undergoing palliative chemotherapy (CT) in the United States (US).

628 Background: Pts with R/R testicular GCT are considered to be incurable, having experienced progressive disease (PD) after salvage conventional-dose CT (CDCT) and/or high-dose CT (HDCT). Therapeutic options are limited to palliative CT, with an estimated real-world (rw) overall survival of 8 months from initiation of their first palliative CT regimen. Understanding TTrwP may help further inform clinical care. Methods: The Komodo Research Database (KRD; 01/2016-03/2023) was used to identify adult males in the US with testicular GCT who received palliative CT after salvage CT. TTrwP was estimated using Kaplan-Meier analysis and defined as time from index date (initiation of first palliative CT regimen) to first rw proxy of PD, which included 1) radiation after the first cycle of palliative CT, 2) treatment addition/switch, 3) treatment discontinuation prior to death, 4) hospice admission, or 5) death. Treatments received pre-/post index were described. Results: Among 248 pts receiving palliative CT, 97 (39.1%) had sufficient data to confirm prior salvage CT and, of those, 80 (82.5%) had ≥12 months of potential follow-up for outcome assessment. Median age was 33.0 years and most pts had commercial (51.3%) or Medicaid (42.5%) coverage. Before index, 49 (61.3%) pts were exposed to HDCT with or without CDCT (+/- CDCT) and 31 (38.8%) pts to CDCT only. Index regimens included gemcitabine-oxaliplatin (47.5%), oral etoposide (13.8%), gemcitabine-paclitaxel (13.8%), and gemcitabine-oxaliplatin-paclitaxel (7.5%). Median (95% confidence interval) TTrwP was 3.8 (2.6-4.7) months overall, 3.5 (2.3-4.7) months after prior HDCT +/- CDCT, and 4.0 (1.7-6.6) months after CDCT only. First PD events included radiation (32.5%), treatment discontinuation (31.3%), and treatment addition/switch (22.5%), occurring at a median of 2.8, 2.1, and 4.7 months from index, respectively. Death was observed for 91.3% of pts and occurred at a median of 2.4 months from PD event, including 3 (3.8%) pts with death as their PD event (Table). Conclusions: This study is the first to use rw proxies for PD in claims data to estimate TTrwP in pts with R/R testicular GCT. With no curable treatment options remaining, the short TTrwP highlights the poor outcomes in this patient population and need for novel therapies to improve clinical outcomes. RW PD events observed in pts with R/R GCT (N=80). First PD event N (%) Time to event (months), median [IQR] Death, N (%) Time from PD event to death (months), median [IQR] Radiation 26 (32.5%) 2.8 [1.4 - 4.6] 26 (100.0%) 3.0 [1.9 - 6.3] Treatment discontinuation 25 (31.3%) 2.1 [1.0 - 3.9] 25 (100.0%) 1.8 [1.3 - 3.1] Treatment addition/switch 18 (22.5%) 4.7 [3.0 - 6.1] 16 (88.9%) 3.8 [3.2 - 6.1] Hospice 3 (3.8%) 9.9 [0.5 - 17.1] 3 (100.0%) 0.3 [0.3 - 3.0] Death 3 (3.8%) 30.4 [3.8 - 32.0] 3 (100.0%) 0.0 [0.0 - 0.0] No PD 5 (6.3%) – 0 (0.0%) –