First-in-human, phase I study of TT-00420, a multiple kinase inhibitor, as a single agent in advanced solid tumors.
Authors: Piha-Paul Sarina Anne , Xu Binghe , Raghav Kanwal Pratap Singh , Meric-Bernstam Funda , Janku Filip , Dumbrava Ecaterina Elena , Fu Siqing , Karp Daniel D. , Rodon Ahnert Jordi , Conley Anthony Paul , Mott Frank , Ajani Jaffer A. , Hong David S. , Fan Ying , Peng Peng , Levin Wendy J. , Ngo Brenda , Ru Qinhua Cindy , Wu Frank , Javle Milind M. 
Published: June 2022

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Background: TT-00420 is a spectrum-selective multi-kinase inhibitor that targets cell proliferation, angiogenesis, and immune-oncology pathways by inhibiting Aurora kinases A/B and Janus kinases (JAK) involved in cytokine signaling and receptor tyrosine kinases (FGFRs and VEGFRs) involved in the tumor microenvironment. TT-00420 has demonstrated anti-tumor activity in both in vitro and in vivo preclinical models of solid tumors, including triple-negative breast cancer (TNBC) and cholangiocarcinoma (CCA). Methods: This phase I, first-in-human, dose escalation and expansion study of TT-00420 ( NCT03654547 ) enrolled adult patients with advanced or metastatic solid tumors. Capsules in 1 mg or 5 mg formulation were administered orally once daily in 28-day cycles. Dose escalation was guided by Bayesian modeling with overdose control. The primary safety endpoints were to determine dose limiting toxicities (DLTs) and a dose recommended for dose expansion (DRDE). Secondary endpoints included pharmacokinetics (PK) and preliminary efficacy evaluated per RECIST v1.1 criterion. Results: As of February 7, 2022, 48 advanced solid tumor patients were enrolled in the study, and received at least one dose of TT-00420 in 7 dose levels: 1 mg q.d. (N = 1), 3 mg q.d. (N = 1), 5 mg q.d. (N = 4), 8 mg q.d. (N = 10), 10 mg q.d. (N = 6), 12 mg q.d. (N = 20), and 15 mg q.d. (N = 6). DLTs were observed in 3 out of 40 DLT-evaluable patients, including 1 patient at 8 mg q.d. who had Grade (Gr) 3 palmar-plantar erythrodysaesthesia syndrome and 2 patients at 15 mg q.d. who both had Gr 3 hypertension. Among the twenty (20) safety evaluable patients treated at 12 mg, the DRDE, drug-related TEAEs included hypertension (n = 11, 55.0%; Gr 3: n = 6, 30%); diarrhea (n = 7, 35%, Gr 3: n = 1, 5%); mucosal inflammation (n = 7, 35%; Gr 3: n = 1, 5%); palmar-plantar erythrodysaesthesia syndrome (n = 6, 30%; Gr 3: n = 0, 0%); and vomiting (n = 4, 20%; Gr 3: n = 0, 0%). No grade 4 suspected adverse events were reported. Out of 42 patients who had at least one post-baseline scan, 7 (16.7%) had a best response of partial response (PR) and 22 (52.4%) had stable disease (SD). Among 7 PRs, 3 were CCA patients (one for each treated at 8 mg, 10 mg, or 12 mg), 2 were TNBC patients (one for each at 10 mg, or 12 mg), 1 was HER2-negative BC patient at 12 mg, and 1 was CRPC patient at 12 mg. Sustainable stable disease for six months or longer was observed in patients with colon cancer (n = 1), head and neck cancer (n = 1), and peritoneal mesothelioma (n = 1). Conclusions: TT-00420 monotherapy was well tolerated and had favorable PK characteristics. The TEAEs observed in dose escalation and dose expansion cohorts were manageable with concomitant treatment and/or dose interruptions of TT-00420 and reversible upon the discontinuation of TT-00420 treatment. Taking safety, efficacy and clinical PK into consideration, 10 mg p.o. q.d. was recommended for phase II study of TT-00420 in patients with advanced CCA. Clinical trial information: NCT03654547.