Retrospective Database Analysis of Patterns of Zoledronic Acid (ZOL) Treatment in Patients with Multiple Myeloma (MM) and Malignant Bone Lesions (BM).
Authors: Spencer Donna , Kaura Satyin , Perez Jose Ricardo , Henk Henry J 
Published: October 2019

Abstract
Abstract 4944

Background
MM patients with BM may be treated with a variety of anti-cancer and bone treatments. The purpose of this study was to examine the use of ZOL, a therapy administered intravenously to reduce or delay skeletal complications, in the real-world treatment of adult patients with MM and BM. Of special interest to the study was the use of ZOL in the context of bortezomib (BOR) and lenalidomide (LEN).

Methods
Claims-based analysis of commercial and Medicare data from a large US managed care plan and a 45-health plan database was conducted to examine the use of ZOL in the treatment of adult patients (18 years and older) with MM and BM. Patients with at least one claim for ZOL and evidence of MM diagnosis and BM diagnosis were included. The identification period was 7/1/03 – 7/31/08 for the large US commercial health plan, 7/1/03 – 12/31/07 for the Medicare plan, and 7/1/04 – 6/30/08 for the 45-health plan database. The sequencing, number, and duration of ZOL treatments were analyzed. Continuous enrollment in the health plan for six months before and three months following the index date was required. Patients were followed until they disenrolled from the plan (including due to death), or the end of the study's follow-up period.

Results
The study sample included 8,632 of which 4,260 patients were enrolled in their health plan for at least one year following ZOL initiation, with a median follow-up length of 21.2 months (range = 12 months to 5.3 years). Among the 4,260 patients, 38.7% were men, the mean age was 60.7 ± 11.9 years, and the average Charlson comorbidity index score was 5.4 (SD=2.2). Accounting for variable follow-up during the study period, patients had an average of 7.01 ZOL administrations per person year. Approximately 63.5% (n=2,707) patients were still receiving ZOL at the end of the first year following ZOL initiation. The majority of patients (90.2%, n=3,841) treated with ZOL were not treated with either BOR or LEN. Approximately 93.0% of these cases received other types of anti-cancer treatments (e.g., melphalan, thalidomide, prednisone, and other chemotherapies) at some point during the study period. For 345 (8.1%) patients, BOR or LEN initiation followed the start of ZOL, and 185 (53.6%) of these cases started BOR or LEN within the first year following initiation of ZOL. Among those initiating BOR or LEN, the median time from ZOL initiation was 337 days (range = 5 to 1,594 days). In 19 (0.4%) cases, ZOL was started at the same time as BOR or LEN, and in 55 (1.3%) cases, ZOL treatment followed BOR or LEN initiation.

Conclusions
According to this retrospective database analysis, the vast majority of patients with MM and BM who initiate ZOL do not go on to receive BOR or LEN within the year following ZOL initiation. Among patients enrolled in the health plan for at least one year following ZOL initiation, the majority of patients remained on ZOL treatment. As anticipated, this study showed that the overwhelming proportion of MM patients with BM using ZOL were being treated with anti-cancer therapies, but only approximately 10.0% with either BOR or LEN.

Disclosures
Kaura: Novartis: Employment, Equity Ownership. Perez:Novartis: Employment, Equity Ownership.