Effect of pembrolizumab (pembro) on hepatitis B viral (HBV) load and aminotransferase (ALT) levels in patients (pts) with advanced hepatocellular carcinoma (aHCC) in KEYNOTE-224 and KEYNOTE-240.

4587 Background: The effect of PD-1 inhibition on HBV infection is unclear, and pts with HBV are often excluded from trials. This analysis evaluated HBV viral load and liver function (ALT levels) in pts with HBV infection in 2 trials of pembro: KEYNOTE-224 and KEYNOTE-240. Methods: Eligible pts with aHCC post first-line sorafenib and controlled HBV received pembro 200 mg IV Q3W until progression. Pts with active HBV (HBsAg positive and/or HBV DNA detectable) and inactive HBV (anti-HBc positive, HBsAg negative, and HBV DNA not detectable) at baseline (BL) were included. Results: Of 104 pts in KEYNOTE-224 and 413 pts in KEYNOTE-240, 8 (7.7%) and 101 (24.5%) had active HBV and 13 (12.5%) and 102 (24.7%) had inactive HBV, respectively. All pts with HBV received nucleos(t)ide analogs. In KEYNOTE-240, 2 (2.8%) pts with active HBV in the pembro arm and 1 (3.4%) in placebo (pbo) had a > 1 log increase (incr) of HBV DNA and 1000 IU/mL over BL; none in the pembro arm were associated with ALT elevation. No pts with inactive HBV in KEYNOTE-240 and no pts in KEYNOTE-224 had a > 1 log incr and 1000 IU/mL over BL. No pts in KEYNOTE-224 and 28 (38.9%) with active HBV and 1 (1.4%) with inactive HBV in the pembro arm, and 8 (27.6%) with active HBV and 0 with inactive HBV in the pbo arm in KEYNOTE-240 had a > 1 log decrease (decr) in HBV DNA. Conclusions: Few pts with aHCC and HBV had viral load incr with pembro. In KEYNOTE-240 no clinically meaningful differences between pembro and pbo were observed. ALT elevation was not associated with viral load incr with pembro. These data suggest that pembro is unlikely to significantly affect underlying HBV infection in pts with aHCC receiving HBV antiviral therapy. Clinical trial information: KEYNOTE-224, NCT02702414; KEYNOTE-240, NCT02702401 . [Table: see text]