Safety of the cyclin dependent kinase 9 (CDK9) inhibitor FIT039 for cervical intraepithelial neoplasia (CIN) 1 or 2 in a phase I/II trial.

Abstract

3022 Background: Human papillomaviruses (HPVs) infect uterine cervical epithelial cells, leading to cervical intraepithelial neoplasia (CIN) and cervical cancer. However, there is no treatment for HPV infection in the uterine cervix prior to vaccination. We recently reported that cyclin dependent kinase 9 (CDK9) plays a critical role in viral RNA transcription of DNA viruses such as HPVs in host cells, and that FIT-039, a specific inhibitor of CDK9, suppresses the proliferation of several DNA viruses. Here, we evaluated the safety and antiviral effect of a FIT039-releasing vaginal tablet (FIT039CT) for CIN1 or 2 (CIN1/2). Methods: A multi-institutional, single-blind, placebo-controlled randomized phase I/II clinical trial involving 2 cohorts was designed to evaluate the safety of transvaginal FIT039CT for CIN1/2 as follows:. In the first cohort, 8 healthy women were randomized into FIT039CT (50mg/day or 100mg/day) or control group. In the second cohort, 14 women with a primary diagnosis of CIN1/2 were randomized into either FIT039CT (100mg/day) or control group. The primary endpoints were adverse events and plasma concentrations of FIT039. Results: 22 patients (8 volunteers, 11 CIN1 and 3 CIN2) were enrolled. There were no serious adverse events. Adverse events considered related to treatment were mild (vaginal discharge Grade 1: FIT039CT 16/17 women [94%] vs placebo 2/6 [33%]) and self-limiting in both cohorts. No patient discontinued this study due to adverse events. Maximum concentration (C max) and terminal elimination half-life (t 1/2) of serum FIT039 concentrations after single transvaginal treatment of FIT039CT were similar between the two doses as follows; C max (mean ± standard deviation) was 4.5 ± 0.5 ng/mL (50mg/day) and 4.4 ±1.4 ng/mL (100mg/day) at 6-7 hours; mean t1/2 was 14.8 ± 2.1 hours (50mg/day) and 12.1 ± 2.6 hours (100mg/day) hours. Conclusions: This study demonstrated the safety and validity of transvaginal FIT039CT once a day and may contribute to the development of an antiviral agent that can cure CIN1/2, and supports the design of the ongoing phase 2 clinical study. Clinical trial information: jRCT2051180201.