gms | German Medical Science

Background and current state of (inter)national research: Real-world evidence (RWE) can be defined as information obtained from other sources outside clinical or academic research settings. This evidence can be used as a complement to Health Technology Assessment to improve the process of decision-making. For High-Price Drugs the Superintendencia de Servicios de Salud (SSS) developed a reimbursement system called Sistema Único de Reintegros. This program makes the process of decision-making more transparent.

Colorectal cancer (CRC) is the second most frequent cancer in Argentina, representing 11.8% of the total cases in both sexes. There are three biologic drugs for metastatic CRC: bevacizumab, cetuximab and panitumumab.

Research questions and objectives: The main objective of this study is to be able to demonstrate through real data how the effectiveness of treatments can be improved and thus the effectiveness of the health system. We determine the survival of metastatic colorectal cancer (mCRC) in patients belonging to the Social Security health sector of Argentina, treated with at least one of the three biologic drugs (bevacizumab, cetuximab, or panitumumab). We also aimed to evaluate the effect of different risk factors (type of biologic, tumor sidedness) on the overall survival (OS), progression free survival (PFS) and clinical outcomes of the patients.

Methods or hypothesis: We analyzed retrospectively the clinical records of the reimbursement system, taking patients with mCRC who were candidates to receive bevacizumab or cetuximab or panitumumab (N=1,359). We used the information available between January 1^st 2009 and March 1^st 2019. Kaplan-Meier analysis was used to estimate de OS and the PFS. We used Cox regression to obtain Hazard Ratios (HR) with 95% Confidence Intervals (CI95%) for the association between:

1.

type of biologic treatment and OS,

2.

tumor sidedness and OS.

Results: We analyzed the data of 1,359 patients with diagnosis mCRC. 61.2% were males. The mean age was 55.2 (SD+/- 11.4). The stage at diagnosis was IV in 60% of the patients, III in 34%, and II in only 6%. The 35.5% were left-sided, 13.5% right sided and 51% unknown. Bevacizumab was the biologic drug used in 65.5% of the patients, cetuximab in 26% and panitumumab in 8.5%. These treatments were applied in combination with oxaliplatin in 52% of the patients, irinotecan in 42%, and in mixed combination in 6% of the patients. By KRAS mutation status: 53% were not mutated, 17% were mutated and 30% were undetermined. The median OS for all the patients was 18.08 months (CI95% 16.98-19.18). The median PFS for all the patients was 7.99 months (CI95% 7.57-8.35). The median overall survival was not different when we compared patients who received bevacizumab, cetuximab, or panitumumab (p=0.63). There was not difference in OS when we compared patients according to the mutation status (HR 0.95 CI95% 0.80-1.14) or the tumor sidedness (HR=0.86 CI95% 0.71-1.05).

Discussion: The results can demonstrate that the information that can be obtained from this National Health System can be very valuable to have a more efficient and affordable system.