Muhsin, Mann

408 Background: Standard of care for CCA/GBC is C-G therapy. MAbs (ATZ, pembrolizumab) targeting PD-L1 show promise in treating CCA/GBC. Hyaluronan (HA), which may impede drug and immune cell access, is high (67%) in CCA/GBC tumors. PEGPH20 enzymatically degrades HA. HALO 110-101 (NCT03267940) evaluates safety and activity of PEG-C-G-ATZ or PEG-C-G versus C-G in CCA/GBC pts. Methods: This study comprises two parts. In Run-In (RI) six pts were enrolled in PEG-C-G arm, then six pts in PEG-C-G-ATZ arm. Eight additional pts may be enrolled for tolerability. In Expansion (EX), up to 50 pts will be enrolled for efficacy. Treatment (Tx) cycle is 21 days (d). PEGPH20 dose is 3 μg/kg on d1, eight and 15 and ATZ dose is 1200 mg (one–three hours after PEGPH20) on d1 (PEG-C-G-ATZ only). C-G is dosed at 25 mg/m2 C and 1000 mg/m2 G on d2 and nine. In C-G arm (EX only), C-G is dosed on d1 and 8. Primary endpoints are ORR (RECIST v1.1), AEs (NCI CTCAE v4.03), laboratory/safety (RI only); secondary endpoints are PK; DOR, DCR, PFS; OS, OS by PD-L1 expression; ORR and DOR (imRECIST). Results: Eighteen pts have been enrolled (nine in each arm). The mean (SD) age is 57 (12.2) yrs in PEG-C-G and 69 (8.8) yrs in PEG-C-G-ATZ. 56% were men. All pts experienced ≥ 1 AE. The most common AEs are nausea, fatigue (50% each); decreased appetite (44%); anemia, constipation (39% each); thrombocytopenia, oedema peripheral, AST increased, myalgia (33% each). To date, there has been one dose-limiting toxicity (febrile neutropenia) in the PEG-C-G arm. There have been no deaths due to AEs. Conclusions: The overall safety profile of PEGPH20 + C + G ± ATZ is acceptable and consistent with safety observed for the individual components. There were no DLTs resulting in a dose reduction of PEGPH20, which is being dosed at 3 μg/kg in the EX phase. Clinical trial information: NCT03267940. [Table: see text]

TPS543 Background: Cholangiocarcinoma (CCA) is treated with CIS and GEM (CISGEM), but prognosis is poor. Hyaluronan (HA) accumulation in solid tumors may impede drug and immune cell access. PEGPH20 targets tumors that accumulate HA (HA-high). This study (NCT03267940) plans to enroll 70 subjects to evaluate the safety and activity of PEGPH20 + programmed cell death-ligand 1 (PD-L1) agent atezolizumab, (PEGCISGEMATEZO), & PEGPH20 + CISGEM (PEGCISGEM) in HA-high subjects with CCA and gallbladder cancer. Study will comprise initial run-in and expansion portions. Primary endpoints include incidence of AEs and other laboratory/safety parameters and ORR (RECIST v1.1). Secondary endpoints include PK parameters; DOR, DCR, PFS, and ORR (RECIST v1.1 and immune-modified RECIST); and OS and OS by PD-L1 expression. Methods: ~6 HA-high subjects will be enrolled in PEGCISGEM arm run-in portion and undergo at ≥1 cycle; subsequently, 6 HA-high subjects will enter the PEGCISGEMATEZO arm. Treatment period will be 21-day cycles. In the expansion portion, ~50 HA-high subjects will be enrolled and randomized in a 2:2:1 ratio into PEGCISGEMATEZO, PEGCISGEM, and CISGEM arms. PEGPH20 is planned to be administered at 3.0 μg/kg on Days 1, 8 and 15 of all cycles in both portions. ATEZO will be administered at 1200 mg 1–3 hours after PEGPH20 on Day 1 of each 21-day cycle in the PEGCISGEMATEZO arm in both portions. In the PEGCISGEM & PEGCISGEMATEZO arms, dosing schedule for CISGEM is the same during both portions, with administration of 25 mg/m2 CIS and 1000 mg/m2 GEM on Days 2 and 9 of each cycle. In CISGEM control arm (expansion only), dosing schedule will be on Days 1 and 8 of each cycle. Treatment will continue until death, withdrawal of consent, disease progression, or unacceptable toxicity. Tumor response will be evaluated using RECIST v1.1. AEs will be graded per NCI CTCAE v4.03. Tumor samples will be tested retrospectively for PD-L1 expression. Safety data will be periodically monitored by an independent data monitoring committee. Clinical trial information: NCT03267940.