Paclitaxel, ifosfamide & cisplatin (TIP) as second-line therapy for germ cell tumors (GCT):Long-term follow-up and expansion cohort.

Abstract

386 Background: TIP was established as an effective second-line regimen in a phase II study of 46 patients (pts) with relapsed GCT and favorable risk factors (Kondagunta, JCO 2005). Here, we report long-term follow up from this trial and outcomes for additional pts who subsequently received TIP off protocol. Methods: Eligiblepts included those who received TIP on the original phase II trial (original cohort) or who received TIP following study closure but would have met the trial inclusion criteria (expansion cohort). An additional exploratory cohort was comprised of pts with unfavorable risk factors who would not have met the original trial criteria. The primary endpoint was favorable response rate (FRR), which included complete responses (CR) and partial responses with negative markers (PR-). Overall survival (OS), progression free survival (PFS), and relapse rates were also evaluated. Results: Of 204 pts who received TIP for GCT at our institution from 5/1994 to 7/2019, 87 (original cohort, n=46; expansion cohort, n=41) met the inclusion criteria and were evaluable for the main analysis. An additional 17 pts were analyzed in the exploratory cohort (unfavorable risk factor: PR- lasting <6months or IR, n=13; prior adjuvant therapy, n=4). 100 pts were excluded due to participation in an ongoing clinical trial (n=17), receipt of TIP as their first regimen (n=74) or in the adjuvant (n=3) setting, or insufficient data (n=6). Baseline characteristics and efficacy data are displayed in the table below. In the main cohort, 70/87 (80%) pts achieved a favorable response. With median follow-up of 10.2 years (yrs) [original, 14.3 yrs; expansion 6.5 yrs] 26 deaths were observed. 5yr and 10yr OS rates were 72% (95% CI 63, 83) and 69% (95% CI 59, 80) respectively. 5yr and 10yr PFS were 70% (95% CI 61, 81) and 67% (95% CI 57, 78). In the exploratory cohort, there were 7 deaths at median follow-up of 6.2 yrs with 5yr OS of 56% (95% CI 35, 87) and 5yr PFS of 59% (95% CI 40, 88). Conclusions: Long-term follow-up and additional experience supports the use of TIP as second-line therapy for GCT. Similar outcomes were seen for our exploratory and main cohorts, suggesting benefit with TIP outside of those with a favorable prognosis. [Table: see text]