PURPOSE The immunomodulatory effect of lenvatinib (a multikinase inhibitor) on tumor microenvironments may contribute to antitumor activity when combined with programmed death receptor-1 (PD-1) signaling inhibitors in hepatocellular carcinoma (HCC). We report results from a phase Ib study of lenvatinib plus pembrolizumab (an anti–PD-1 antibody) in unresectable HCC (uHCC). PATIENTS AND METHODS In this open-label multicenter study, patients with uHCC received lenvatinib (bodyweight ≥ 60 kg, 12 mg; < 60 kg, 8 mg) orally daily and pembrolizumab 200 mg intravenously on day 1 of a 21-day cycle. The study included a dose-limiting toxicity (DLT) phase and an expansion phase (first-line patients). Primary objectives were safety/tolerability (DLT phase), and objective response rate (ORR) and duration of response (DOR) by modified RECIST (mRECIST) and RECIST version 1.1 (v1.1) per independent imaging review (IIR; expansion phase). RESULTS A total of 104 patients were enrolled. No DLTs were reported (n = 6) in the DLT phase; 100 patients (expansion phase; included n = 2 from DLT phase) had received no prior systemic therapy and had Barcelona Clinic Liver Cancer stage B (n = 29) or C disease (n = 71). At data cutoff, 37% of patients remained on treatment. Median duration of follow-up was 10.6 months (95% CI, 9.2 to 11.5 months). Confirmed ORRs by IIR were 46.0% (95% CI, 36.0% to 56.3%) per mRECIST and 36.0% (95% CI, 26.6% to 46.2%) per RECIST v1.1. Median DORs by IIR were 8.6 months (95% CI, 6.9 months to not estimable [NE]) per mRECIST and 12.6 months (95% CI, 6.9 months to NE) per RECIST v1.1. Median progression-free survival by IIR was 9.3 months per mRECIST and 8.6 months per RECIST v1.1. Median overall survival was 22 months. Grade ≥ 3 treatment-related adverse events occurred in 67% (grade 5, 3%) of patients. No new safety signals were identified. CONCLUSION Lenvatinib plus pembrolizumab has promising antitumor activity in uHCC. Toxicities were manageable, with no unexpected safety signals.

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Intracellular tumor antigens presented on the cell surface in the context of human leukocyte antigen (HLA) molecules have been targeted by T cell–based therapies, but there has been little progress in developing small-molecule drugs or antibodies directed to these antigens. Here we describe a bispecific T-cell engager (BiTE) antibody derived from a T-cell receptor (TCR)-mimic monoclonal antibody (mAb) ESK1, which binds a peptide derived from the intracellular oncoprotein WT1 presented on HLA-A*02:01. Despite the very low density of the complexes at the cell surface, ESK1-BiTE selectively activated and induced proliferation of cytolytic human T cells that killed cells from multiple leukemias and solid tumors in vitro and in mice. We also discovered that in an autologous in vitro setting, ESK1-BiTE induced a robust secondary CD8 T-cell response specific for tumor-associated antigens other than WT1. Our study provides an approach that targets tumor-specific intracellular antigens without using cell therapy and suggests that epitope spreading could contribute to the therapeutic efficacy of this BiTE.

TPS4152 Background: Len, an inhibitor of VEGF receptors 1-3, FGF receptors 1-4, PDGF receptor α, RET, and KIT, is approved for first-line treatment of unresectable HCC (uHCC) based on the open-label phase 3 REFLECT study in which len showed noninferior overall survival (OS) and significantly improved objective response rate (ORR), progression-free survival (PFS), and time-to-progression (TTP) vs sorafenib. In the phase 2 KEYNOTE-224 study of pembro (a PD-1 inhibitor) as second-line treatment of advanced HCC, pembro showed meaningful clinical efficacy in pts previously treated with sorafenib, with median PFS 4.9 mo, median OS 12.9 mo, and a manageable safety profile. In results from the phase 1b KEYNOTE-524 trial, len+pembro was well-tolerated, with promising antitumor activity in pts with uHCC. LEAP-002 is a phase 3 study to evaluate the safety and efficacy of len+pembro vs len+placebo as first-line therapy for advanced HCC. Methods: Eligible pts are ≥18 y and have HCC confirmed by radiology, histology, or cytology; ECOG PS 0/1; BCLC stage C or stage B disease not amenable to locoregional therapy or curative treatment approach; CP class A liver score within 7 days before study; and ≥1 measurable lesion by RECIST v1.1. Pts with past or ongoing HCV infection and those with controlled HBV are eligible. 750 pts will be randomized 1:1 to receive len 12 mg (body weight [BW] ≥60 kg) or 8 mg (BW <60 kg) orally once daily plus pembro 200 mg or placebo IV Q3W. Pembro and len will be administered until disease progression or unacceptable toxicity, with a maximum 35 cycles for pembro. Stratification will be by geographic region (Asia vs Japan and Western regions); macroscopic portal vein invasion or extrahepatic spread or both (yes or no); alpha fetoprotein ≤400 ng/mL vs >400 ng/mL; and ECOG PS 0/1. Primary end points are PFS per RECIST v1.1 by blinded independent central review (BICR) and OS. Secondary end points are ORR, duration of response, disease control rate, and TTP per RECIST v1.1 by BICR, efficacy per modified RECIST, pharmacokinetics, and safety. Imaging assessments will be performed Q9W on study. AEs will be graded per CTCAE v4.0 and monitored up to 90 days after last dose. Clinical trial information: NCT03713593.

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