Institute of Oncology, Davidoff Cancer Center, Beilinson Hospital, Rabin Medical Center, Petach Tiqva, Israel
Rinat Yerushalmi , Ilan Feldhamer , Sari Greenberg-Dotan , Haim Bitterman , Ariel Hammerman
Background: L and T “beyond progression” (TBP) for MBC pts who progressed on 1st line therapy with T, are both reimbursed in Israel since 1/2010. The relative efficacy of L vs. T when combined with chemotherapy in 2nd line therapy for HER2+ MBC is unknown. In this retrospective database study we compared outcomes of 2ndline L or TBP, in the daily practice ("real life") in Israel. Methods: Using the computerized databases of Clalit Health Services' (CHS), Israel's largest health care provider, we identified all MBC pts that received 2nd line anti HER2 therapy, with either L or TBP after a 1stline protocol containing T, between 1/1/2010 and 31/12/2011. Pts characteristics and treatments were retrieved. The primary end point was overall survival (OS) defined as the time interval between date of initiation of 2nd line anti HER2 therapy and death or last day of follow-up. Secondary endpoint was progression free survival (PFS), defined as duration of 2nd line therapy. Results: The study population included 83 pts (28 L and 55 TBP). Mean age (59.9 vs. 61.4) and average Charlson co-morbidity index score (6.54 vs. 6.13) were similar between the cohorts. The groups differed in rates of prior adjuvant T (32.1% vs. 10.9%, p=0.017). The interim cutoff date for analysis was 31/12/2012 (allowing at least 12 months of follow-up). Median OS was 10.0 months for L pts (95% CI: 7.41–12.59) and was not reached for TBP, with a total of 31 deaths: 19 [67.9%] in the L group and 22 [40.0%] in the TBP group. A Cox regression showed an adjusted hazard ratio (HR) of 1.44 (95% CI 0.74-2.81), not significant (p=0.28).Prior adjuvant therapy with T was found to be a significant cofounder; HR=3.16 (95% CI 1.52-6.56). Median PFS was 6.0 months (95% CI: 4.31–7.69) for L and 7.0 months (95% CI: 4.30-9.70) for TBP, with a Cox regression adjusted HR of 0.87 (95% CI: 0.50-1.52), not statistically significant (p=0.87). Conclusions: In this retrospective database analysis, our interim results suggest no statistically significant difference in OS and PFS between L and TBP, as 2nd line therapy for HER2+ MBC, however the data showed a strong trend toward a survival benefit with TBP. A longer follow-up is required.
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