Extending the platinum-free interval (PFI) with a non-platinum therapy in platinum (P)- sensitive recurrent ovarian cancer (OC): Results from the SOCRATES retrospective study
5093 Background: Chance of response to P is correlated to PFI (Markman, J Clin Oncol 1991). It has been proposed that extending PFI by interposing non-P therapy increase activity of delayed P retreatment in patients (pts) with P-sensitive recurrent OC, but this strategy is based on data from small series. The SOCRATES study retrospectively assessed the pattern of treatment of a cohort of pts with P-sensitive recurrent OC. Methods: Data of pts treated between 2000 and 2002 at 37 centers were collected in 2005. Pts with recurrent OC were eligible if P-sensitive [interval from end of first line to relapse (RFI) > 6 months]. Results: Data on chemotherapy at relapse were available in 428 pts. RFI was 6–12 months in 40% and >12 months in 60%. Pts received a 2nd (100%), 3rd (80%), 4th (50%), 5th (28%), 6th (12%) line of chemotherapy. 282 pts (65.9%) received P at first relapse (Group A) after a median RFI of 19 months, with a 74.4% response rate (RR) out of 246 evaluable pts. 67 pts (15.7%) received non-P at first relapse after a median RFI of 9.6 months, with a RR of 44.6% out of 56 evaluable pts, and then received P at later relapse after a median PFI of 23 months, with a 57.4% RR out of 47 evaluable pts (Group B). 79 pts (18.5%), with a median RFI of 8.4 months, had a on-P 2nd line with a RR of 28.8% out of 66 evaluable pts, and never received P later (Group C). The difference in RR to P given as 2nd line and delayed P is statistically significant (p = 0.02, Fisher exact test). Median overall survival was 27.2, 26.1 and 16.8 months for Group A, B and C, respectively. Conclusions: With the limits of a retrospective study, our data show that, although P was given in the group B after a similar PFI than in the group A, due to the interposition of a non-P therapy, activity of P was higher when given immediately after relapse than when postponed at subsequent lines. Overall, these data suggest that P-sensitive pts should receive P as soon as possible, and delaying it may preclude the chance of receiving the best treatment. (Study sponsored by GlaxoSmithKline). No significant financial relationships to disclose.