G1 Therapeutics, a Research Triangle Park clinical-stage oncology company, has begun two clinical trials of a new therapy aimed at protecting the bone marrow and immune systems of patients undergoing chemotherapy for small-cell lung cancer.

[The company has raised more than $45 million in venture capital over the past two years. Among its investors is Fred Eshelman, founder PPD and now a venture capitalist.]

The company, a spin-out from the University of North Carolina at Chapel Hill, was bootstrapped with $500,000 in loans from the North Carolina Biotechnology Center in 2011 and 2012 and has since raised more than $45 million in venture capital.

Its two clinical trials will test G1T28, an intravenous therapy, for its ability to inhibit two key proteins involved in cancer development, CDK4 and CDK6. The inhibition temporarily stops hematopoietic stem and progenitor cells from dividing, making them resistant to damage from chemotherapy drugs that target dividing cells.

“More than 300,000 patients per year are treated with chemotherapy for CDK4/6-independent tumors in the U.S. alone, but there are no approved therapies that protect a patient’s bone marrow and immune system from the toxicity it causes,” said Raj Malik, M.D., G1’s chief medical officer. “These phase one-b/two-a proof-of-concept trials will evaluate G1T28’s ability to provide multi-lineage bone marrow and immune system protection in newly diagnosed and previously treated patients with small-cell lung cancer.”

In an earlier Phase one-a trial, G1T28 was well tolerated and demonstrated robust, reversible, arrest of bone marrow stem cells in the G1 phase of the cell cycle. Data from the trial were presented this summer in Chicago at the annual meeting of the American Society of Clinical Oncology.

“G1T28 is a first-in-class approach that could change the oncology treatment paradigm by mitigating myelosuppression and improving tumor responses and health outcomes,” said G1 CEO Mark Velleca. “We are thrilled to have the first patient dosed and to assess these potential benefits.”

One trial will test G1T28 in about 80 patients newly diagnosed with extensive-stage small-cell lung cancer who will receive the chemotherapy drugs carboplatin and etoposide. The other trial will test the therapy in about 40 patients previously treated for extensive-stage disease who will receive the chemo drug topotecan.

G1 Therapeutics, named for the G1 phase of the cell cycle, which allows cells to divide, is privately held and has 14 employees.

(C) N.C. Biotechnology Center