G1 Therapeutics, Inc. announced that the independent Data Monitoring Committee (DMC) recommended continuation of the pivotal Phase 3 trial (PRESERVE 2), evaluating trilaciclib in combination with gemcitabine and carboplatin for the first line treatment of metastatic triple negative breast cancer (mTNBC), to the final analysis. This final analysis evaluating Overall Survival (OS) is estimated to occur in the third quarter of 2024 and will be conducted on the intent-to-treat (ITT) population. The DMC did not express any concerns regarding safety or recommend any other changes to the study.

G1 remains blinded to all data as the early stopping criteria were not met during the interim analysis. Trilaciclib, an IV-administered transient CDK4/6 inhibitor, is a first-in-class therapy designed to preserve bone marrow and immune system function during cytotoxic therapy to improve patient outcomes. PRESERVE 2 is a global, multi-center, randomized placebo-controlled, line extension pivotal Phase 3 trial of trilaciclib in patients with locally advanced unresectable or metastatic TNBC.

Patients meeting eligibility requirements were randomized 1:1 to receive either trilaciclib or placebo administered prior to first-line gemcitabine and carboplatin (GCb). The regimen is given intravenously (IV) on Days 1 and 8 in 21-day cycles. Treatment is administered until disease progression.

Breast cancer is the most commonly diagnosed cancer worldwide, with over 2.3 million new cases each year. According to the American Cancer Society, nearly 300,000 new cases of invasive breast cancer are diagnosed annually in the U.S. Triple negative breast cancer makes up approximately 15-20% of such diagnosed breast cancers. TNBC is cancer that tests negative for estrogen receptors, progesterone receptors, and excess HER2 protein.

Because mTNBC cells lack key growth-signaling receptors, patients do not respond well to medications that block estrogen, progesterone, or HER2 receptors. Instead, treating mTNBC typically involves chemotherapy, radiation, and surgery. TNBC is considered to be more aggressive and have a poorer prognosis than other types of breast cancer.

In general, survival rates tend to be lower with mTNBC compared to other forms of breast cancer, and mTNBC is also more likely than some other types of breast cancer to return after it has been treated, especially in the first few years after treatment. It also tends to be higher grade than other types of breast cancer.