OPTIMAL is a 6-center ISW study in non-autoimmune, non-HCV ALTRs ≥3 yrs post-transplant (tx). Studies have shown a correlation between portal inflammation associated with tissue damage and ISW failure, so subjects had a liver biopsy prior to ISW to exclude unfavorable histology and identify tolerance biomarkers.

Methods: 44 screening biopsies were performed 12/15–11/16. Histologic inclusion criteria are noted in Table 1. Histologically eligible/ineligible subjects were compared using Fisher's exact or Wilcoxon rank sum tests with significance at α ≤0.05.

Results: 11/44 subjects were ineligible due to inflammation (n=8) and/or fibrosis (n=3), or bile duct damage (n=1) (Table 2). No significant differences were observed between eligible/ineligible subjects regarding cause of liver failure/blood type/sex/race, IS type, time post-tx, ALT/GGT, or donor type/age/sex. Eligible subjects were significantly older at tx (55 vs. 47, p=0.02) and enrollment (63 vs. 51, p=<0.01).

Conclusion: 1 in 4 biopsies from long-term, stable, non-autoimmune, non-HCV ALTRs harbored subclinical inflammation and/or fibrosis. Increased recipient age at tx and enrollment, but not time from tx, correlated with histologic eligibility for ISW. The natural history and significance of these biopsy findings is unknown and merits further study.

Table 1. Screening Biopsy Inclusion Criteria

Table 2. Characteristics of Eligible/Ineligible Subjects

CITATION INFORMATION: Chandran S, Abecassis M, Levitsky J, Feng S, Humar A, Emond J, Klintmalm G, Demetris A, Much K, Sun L, Priore A, Ikle D, Bridges N, DesMarais M, Burrell B, Markmann J. Subclinical Histologic Findings Are Observed in 25% of Stable Adult Liver Transplant Recipients (ALTRs) Screened for Immunosuppression Withdrawal (ISW): OPTIMAL (NCT02533180). Am J Transplant. 2017;17 (suppl 3).

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