G1 Therapeutics has commenced a Phase Ib/II clinical trial investigating G1T38 in combination with Tagrisso (osimertinib) for the treatment of patients with EGFR-mutant (EGFRm) non-small cell lung cancer (NSCLC).

Tagrisso will be supplied by AstraZeneca under a non-exclusive clinical trial collaboration agreement.

The open-label trial will be conducted in two parts; a safety, pharmacokinetic and dose-finding portion and a subsequent randomised portion.

"G1T38 inhibits tumour cell growth, providing a rationale for combining it with other targeted therapies, including EGFR-TKI inhibitors such as Tagrisso."

Around 145 subjects are expected to be enrolled in the trial.

Primary endpoints of the trial include safety and tolerability, as well as identifying a recommended Phase II dose and progression-free survival (PFS).

Secondary endpoints will include assessment of pharmacokinetics, tumour response and overall survival (OS) rate.

G1 Therapeutics R&D senior vice-president and chief medical officer Raj Malik said: “G1T38 inhibits tumour cell growth, providing a rationale for combining it with other targeted therapies, including EGFR-TKI inhibitors such as Tagrisso.

“In a prior Phase Ia trial, G1T38 had no dose-limiting toxicities and was well tolerated with no impact on liver or cardiovascular function, presenting evidence of a favourable safety and tolerability profile for combination therapy.

“Despite advances in care, lung cancer remains the leading cause of cancer death globally. Non-small cell lung cancer represents the majority of lung cancers, and there is a significant need for new treatment options that improve outcomes for people with this disease.”

G1T38 is currently under development as a potential oral CDK4/6 inhibitor for use in combination with other targeted therapies in multiple oncology indications.

Apart from the new trial, the solution is being evaluated in a separate Phase I/II clinical trial assessing G1T38 in combination with Faslodex for treating people with estrogen receptor-positive, HER2-negative breast cancer.