Redefining liver transplant priority: Waitlist outcomes for HCC after MMaT-3 donor hospital-based allocation reform

In 2022, the United Network for Organ Sharing (UNOS) revised the liver transplant allocation policy to calculate the median MELD at Transplant minus 3 points (MMaT-3) around the donor hospital instead of the transplant center, aiming to reduce disparities among MELD exception candidates. We evaluated the impact of this revised policy on waitlist outcomes in patients with or without hepatocellular carcinoma (HCC). Using the OPTN/UNOS registry, we identified all adult transplant candidates between October 8, 2015, and March 31, 2024, and stratified by policy eras: Pre-MMaT-3 (n=25,580), MMaT-3 Recipient (n=13,311), and MMaT-3 Donor (n=10,027). Fine-Gray competing risk models were performed to estimate waitlist removal due to dropout (death or removal due to clinical deterioration), due to clinical improvement, or transplantation by HCC status. During Pre-MMaT-3, candidates with HCC had a significantly higher probability of transplant than those without HCC [adjusted subdistribution hazard ratio (aSHR) 2.03, 95% CI: 1.95-2.12, p <0.001]. This advantage declined in the MMaT-3 Recipient era (aSHR 1.39, 95% CI: 1.31-1.47, p <0.001) and disappeared in the MMaT-3 Donor era (aSHR 0.98, 95% CI: 0.88-1.09, p =0.73). Waitlist dropout, initially similar for HCC candidates than non-HCC (aSHR 0.93, 95% CI: 0.86-1.01, p =0.08), increased following MMaT-3 Recipient (aSHR 1.21, 95% CI: 1.07-1.36, p =0.01) and Donor (aSHR 2.06, 95% CI: 1.64-2.60, p <0.001) eras. Importantly, within-HCC cohort, waitlist mortality analysis improved after the MMaT-3 Donor era ( aSHR 0.79, p =0.01), while maintaining reduced wait times and stable transplant rates. The MMaT-3 Donor policy effectively deprioritized HCC for transplantation, while improving waitlist mortality within the HCC group. Ongoing evaluation is essential to guide equitable liver allocation.