Association between post-treatment (tx) alpha-fetoprotein (AFP) reduction and outcomes in real-world (rw) U.S. patients (pts) with advanced HCC (aHCC).

Abstract

341 Background: A decrease in post-tx AFP may be associated with improved outcomes in clinical trials. However, the impact of AFP reduction after initiation of a first-line (1L) tyrosine kinase inhibitor (TKI) therapy on outcomes is unclear among pts with aHCC treated in routine clinical practice. Methods: This analysis utilized data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database and included pts with aHCC with ≥2 visits between 1/1/2011-7/31/2019 who received 1L TKI. Pts with a baseline serum AFP value (closest to 1L initiation within -30 to +7 days) and a post-tx AFP value (closest to 8 weeks after 1L initiation within ±2 weeks) were included. Post-tx AFP reduction was defined as a ≥20% decrease from baseline AFP, and no reduction as a <20% decrease or any increase. Rw overall survival (rwOS) was defined as time from post-tx AFP measurement to death (censored at last EHR activity). Rw progression-free survival (rwPFS) was based on clinician documentation and defined as the first progression event or death after post-tx AFP measurement (censored at last clinic note date). Adjusted hazard ratios (aHR) for reduction vs no reduction (reference) were estimated using multivariable Cox proportional hazards models adjusted for potential confounders and baseline AFP. Effect modification was assessed by conducting tests for interactions with analyses stratified by HCC risk factors. Results: 441 pts were included in the study. 8% had documented history (hx) of hepatitis B (HBV), 52% hepatitis C (HCV), 47% obesity/diabetes (DM), 42% heavy alcohol use, and 11% no documented risk factor. Median baseline AFP was 210 ng/mL (IQR 237 - 2981) and 150 ng/mL (IQR 17 - 1311) among pts with reduction (N = 150) and no reduction (N = 291). There was a 35% decrease in hazard of death for pts with reduction vs no reduction (median rwOS 10.3 vs 6.7 months; Table). Similarly, a 35% decrease in hazard of rw progression or death was observed for pts with reduction vs no reduction (aHR=0.65; 95% CI: 0.52-0.81; median rwPFS 4.4 vs 2.4 months). Reduction (vs no) was associated with better rwOS among pts with hx of HCV, obesity/DM or alcohol use vs without the respective risk factor, however, no statistically significant interactions were observed (Table). Conclusions: Results show post-tx AFP reduction may be prognostic for rwPFS and rwOS in pts with aHCC treated with 1L TKI. Further research may clarify if prognostic value differs by HCC risk factor profile. [Table: see text]