G1 Therapeutics has completed enrolment in the Phase III PRESERVE 2 clinical trial of its therapy, Trilaciclib, to treat patients with metastatic triple negative breast cancer (TNBC) receiving chemotherapy.

The international, randomised, multi-centre, placebo-controlled, line extension pivotal trial enrolled 187 patients, who will receive first line trilaciclib or a placebo before gemcitabine and carboplatin (GC).

In the trial, the regimen is given intravenously (IV) on days one and eight in 21-day cycles and the therapy is administered until the disease advances.

Assessing the effect of trilaciclib on overall survival (OS) versus a placebo in patients receiving first-line GC is the trial’s primary endpoint.

Key secondary endpoints include evaluating trilaciclib’s effect on the quality of life of the patients against a placebo.

Myeloprotection measures, overall rate of response (ORR), and progression free survival (PFS) are also included as the secondary endpoints.

The interim OS analysis is expected to be carried out by the company’s data monitoring committee at 70% of events in the second half of next year.

G1 Therapeutics will terminate the trial if it meets the interim analysis stopping rule and report the topline results.

The trial will continue to the final analysis, if it fails.

G1 Therapeutics chief medical officer Dr Raj Malik said: “PRESERVE 2 is exciting as it is evaluating trilaciclib in mTNBC to build on the robust survival benefit observed in the Phase II programme.

“This is a registrational trial for which we have been granted Fast Track designation by the US Food and Drug Administration and, if the results are positive, we will work closely with the FDA to expedite our regulatory filing for approval in this indication.” 

An IV-administered transient CDK4/6 inhibitor, trilaciclib has been designed to preserve bone marrow and immune system function during chemotherapy.