Phase I study of TT-00420, a multiple kinase inhibitor, as a single agent in advanced solid tumors.
Authors: Piha-Paul Sarina Anne Anne , Xu Binghe , Janku Filip , Dumbrava Ecaterina Elena , Fu Siqing , Karp Daniel D. , Meric-Bernstam Funda , Hong David S. , Rodon Ahnert Jordi , Tsimberidou Apostolia Maria , Javle Milind M. , Fan Ying , Peng Peng , Levin Wendy J. , Ngo Brenda , Wang Hui , Sun Caixia , Ru Qinhua Cindy , Wu Frank 
Published: June 2021

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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: The phase I, first-in-human dose escalation and expansion study of TT-00420 is enrolling adult patients with advanced or metastatic solid tumors. TT-00420 capsules in 1 mg or 5 mg formulation are administered orally once daily in 28-day cycles. Dose escalation is guided by Bayesian modeling with overdose control. The primary safety endpoints are to determine dose limiting toxicities (DLTs) and a dose recommended for dose expansion (DRDE). Secondary endpoints include pharmacokinetics (PK) and preliminary efficacy evaluated per RECIST v1.1 criteria. Results: As of February 17, 2021, 40 advanced solid tumor patients were enrolled in dose escalation cohorts 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=12), and 15 mg q.d. (N=6). DLTs were observed in 3 out of 32 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. Suspected adverse events (AEs) reported in ≥ 20% of patients across all tested dose levels include hypertension (any grade: n=17, 42.5%; Gr 3: n=8, 20.0%), diarrhea (n=10, 25.0%; Gr 3: n=1, 2.5%), vomiting (n=9, 22.5%; Gr 3: n=0), palmar-plantar erythrodysaesthesia syndrome (n=9, 22.5%; Gr 3: n=1, 2.5%), and nausea (n=8, 20.0%; Gr 3: n=1, 2.5%). No Gr 4 AEs, regardless of causality, were reported. Out of 26 patients who had at least one post-baseline scan, 4 (15.4%) had a best overall objective response of partial response (PR) and 13 (50.0%) had stable disease (SD). Of the patients who achieved PRs are 2 CCA patients (8 mg q.d., n=1; 10 mg q.d., n=1), 1 HER2-negative breast cancer patient (12 mg q.d.), and 1 TNBC (10 mg q.d.). Both CCA patients with PRs had disease control for ≥ 8 months. Of the patients who achieved SD, 1 salivary gland patient (5 mg q.d.) and 1 CCA patient (10 mg q.d.) had disease control for 8 months, and 2 TNBC patients (5 mg q.d., n=1; 8 mg q.d., n=1) had disease control for 6 months prior to disease progression. Conclusions: Toxicities observed in dose escalation cohorts were manageable with concomitant treatment and/or dose interruptions of TT-00420. 12 mg p.o. q.d. was recommended as the dose for dose expansion cohort for further safety and efficacy evaluation of TT-00420 capsules with focus on enrollment of TNBC and CCA patients. Clinical trial information: NCT03654547.