KHK2455

She was treated with standard concurrent chemotherapy and radiation, as well as a 2-year period of adjuvant temozolomide. She relapsed 2 ½ years after starting her initial therapy and was treated with bevacizumab and lomustine, but she relapsed. She was then placed on a phase 1/2 clinical trial that included KHK2455 and mogamulizumab-kpkc individually and in combination for almost 4 years. She had a rapid demise due to the development of a neutropenic pneumonia and treatment-induced acute myeloid leukemia (AML) and elected for hospice care.

The goal of this analysis was to develop a population pharmacokinetics (PK)-pharmacodynamics (PD) model to characterize KHK2455 exposure and its relationship to response in patients with locally advanced or metastatic solid tumors. Plasma KHK2455 concentration, plasma KYN and TRP concentration were obtained from 36 subjects with locally advanced or metastatic solid tumors who received KHK2455 at 0.3, 1, 3, 10, 30, or 100 mg QD as a monotherapy run-in followed by combination therapy with anti-CCR4 antibody mogamulizumab in this first in human study of KHK2455. A population PK-PD model was established to characterize the KHK2455 exposure and its relationship to response in patients with locally advanced or metastatic solid tumors. The PK-PD model will enable dose optimization simulations for the planned studies.

Six of 26 evaluable patients from all dosing groups achieved durable disease stabilization (≥6 months, RECIST 1.1), and one patient with bevacizumab-resistant glioblastoma demonstrated confirmed partial response (43.5% tumor reduction over a 2-year observation period). Conclusions KHK2455 in combination with mogamulizumab was well-tolerated and manageable at all doses tested, suppressed Kyn production in a dose-dependent and sustained manner, and demonstrated signals of antitumor activity. These data support the continued development of this combination.

Six of 26 evaluable patients from all dosing groups achieved durable disease stabilization (≥6 months, RECIST 1.1), and one patient with bevacizumab-resistant glioblastoma demonstrated confirmed partial response (43.5% tumor reduction over a 2-year observation period). Conclusions KHK2455 in combination with mogamulizumab was well-tolerated and manageable at all doses tested, suppressed Kyn production in a dose-dependent and sustained manner, and demonstrated signals of antitumor activity. These data support the continued development of this combination.

Approximately 44 subjects are planned for enrollment (12 subjects in Part 1 and 32 subjects in Part 2). Clinical trial information: NCT03915405 (sponsor: Kyowa Kirin Pharmaceutical Development, Inc.)