Patterns of second-line chemotherapy for metastatic prostate cancer in the United States.

Abstract

e15193 Background: Patients with prostate cancer progressing from first-line (1L) docetaxel have limited approved treatment options available. Study is to evaluate patterns of second-line (2L) chemotherapy in a US managed care between 2004 and 2010. Methods: Patients with metastatic prostate cancer (mPC) and treated with docetaxel as 1L chemotherapy after July 1, 2004 were ascertained from the OptumInsight database. We evaluated type and timing of chemotherapy and relationships between patient characteristics, physician specialty, healthcare costs and geographic region, 6 months prior to 1L docetaxel and choice of 2L chemotherapy. Results: Patients (N=1,173) were on average 71 yrs old at onset of 1L docetaxel. During a mean follow-up period of 18 months, 38% of patients received 2L treatment. Out of the patients received 2L therapy, 32% received mitoxantrone (MITO), 24% with docetaxel rechallenge (RECH), 14% carboplatin (CARB), and 12% paclitaxel (PAC), plus 11% on Combo therapy. Examination of the 2L treatment groups showed that during the 6 months prior to 1L docetaxel, the RECH group (n=101) was older (73yrs), had fewer hospital admissions (12%), lower comorbidity burden [Charlson Comorbidity Index (CCI)=7.4], lower total healthcare costs ($10,083), and 78% seeing an oncologist; relative to MITO group (n=143) with 70 yrs, 16% hospital admissions, CCI of 7.5, total healthcare costs of $12,074, and 80% seeing an oncologist. The combo group (n=52) was 66 years old, with 19% hospital admissions, CCI of 8, total healthcare costs of $20,505, and 92% seeing an oncologist. Median time to MITO from the start of 1L docetaxel was 184 days, 309 days to RECH and 223 days to Combo therapy. Midwest (36%) and West (37%) were more frequently using MITO than Northeast (26%) and South (31%), while RECH was more frequently used in Northeast. Conclusions: Patients with mPC in US were most frequently treated with MITO or RECH as 2L chemotherapy after 1L docetaxel. MITO was also given sooner than RECH, hence a valid comparator for comparative effectiveness evaluation on new 2L therapy. Rechallenge with docetaxel increased with time and was given to patients with lower disease burden and healthcare costs than the MITO or Combo group.