luvixasertib (CFI-402257)

P1/2, N=37, Active, not recruiting, Canadian Cancer Trials Group | Phase classification: P2 --> P1/2 | Trial completion date: Dec 2023 --> Dec 2024

P1/2, N=44, Recruiting, Treadwell Therapeutics, Inc

CFI-402257 is a potent inhibitor of TTK. It is well tolerated with manageable TEAEs, no dose limiting or treatment limiting toxicities, and no treatment related deaths. Dose expansion in the patient population of interest will commence.

P2, N=37, Active, not recruiting, Canadian Cancer Trials Group | Trial primary completion date: Jun 2023 --> Nov 2022

This increase was induced by treatment with CFI-402257, a selective inhibitor of the mitotic kinase TTK, which plays a key role in spindle-assembly checkpoint (SAC) regulation...Overall, these results suggest that GSCs have an enhanced ability to tolerate the negative consequences of aneuploidy on survival as well as on radiosensitivity. Such aneuploid tolerance may provide a mechanism through which GBMs exploit karyotype diversity to survive under harsh environmental conditions and after treatment.

Background: TTK (also known as MPS1), a dual-specificity serine-threonine kinase, is critical for the spindle assembly checkpoint, chromosome alignment, and error correction in mitosis. CFI- 402257 is well tolerated as mono and combination with fulvestrant. Efficacy signals are emerging with pts in the combo cohort demonstrating anti-tumor activity. Additional efficacy will be updated at the time of the presentation.

CFI-402257 and paclitaxel was well tolerated, with neutropenia as the main toxicity. DL3 (168mg) was selected as RP2D. Phase 2 ORR and CBR was 5.9% and 58.8%, respectively; during Phase 2, the 17 evaluable patients from stage 1 did not meet the pre-specified threshold for anti-tumor activity to proceed to stage 2 and the trial was closed to accrual on April 7, 2022.

In these models, inhibition of TTK with CFI-402257 induces premature chromosome segregation, leading to excessive mitotic segregation errors, DNA damage, and cell death. These findings nominate the TTK inhibitor CFI-402257 as a therapeutic strategy for a defined subset of ER breast cancer patients who develop resistance to CDK4/6i.

Further, CFI-402257 improved survival in HCC-bearing mice treated with anti-PD-1, suggesting the possibility of combination treatment with immune checkpoint inhibitors in HCC patients. In summary, our study characterized CFI-402257 as a potential therapeutic for HCC, both used as a single agent and in combination therapy.

P1/2, N=44, Recruiting, Treadwell Therapeutics, Inc | Not yet recruiting --> Recruiting

We demonstrated that TTK promotes the TMZ resistance of GBM cells by inducing autophagy in vitro and in vivo. The use of a TTK inhibitor in combination with TMZ might help to overcome TMZ resistance and improve therapy efficiency in GBM.

P1, N=52, Active, not recruiting, University Health Network, Toronto | Recruiting --> Active, not recruiting | Trial completion date: Jan 2022 --> May 2027 | Trial primary completion date: Jan 2022 --> May 2027

Safety endpoints include incidence of treatment emergent adverse events. Exploratory objectives include characterization of protein and molecular alterations relevant to the cell cycle and CFI-402257 response.

P1/2, N=44, Not yet recruiting, Treadwell Therapeutics, Inc