San Diego Business Journal

On the heels of auspicious clinical trial results, San Diego-based Oncternal Therapeutics completed a reverse merger with Tennessee’s GTx, it was announced June 10.

At deal close, earlier Oncternal stockholders held about 77.5 percent of the combined company’s outstanding shares, according to a news release. Oncternal changed its ticker symbol on the Nasdaq Capital Market to ONCT.

James Breitmeyer, Oncternal’s co-founder, retained his role as CEO. David Hale, a San Diego biotech veteran, is still board chairman. The company, which spun out of UC San Diego, remains located in San Diego.

“We believe that the closing of the merger signifies a transformative event that will provide Oncternal with the opportunity to achieve its next level of corporate growth as we continue to advance our promising oncology drug candidates through development,” said Breitmeyer.

Its lead drug candidate, cirmtuzumab, is in phase 1/2 testing in combination with the drug ibrutinib for chronic lymphocytic leukemia, a blood and bone marrow disease. Pharmaceutical AbbVie owns the rights to ibrutinib.

Interim data released June 3 showed the combo demonstrated a 91.7% overall objective response rate among a dozen patients. Three of the patients demonstrated a complete response — the absence of detectable cancer.

“The cirmtuzumab and ibrutinib combination has demonstrated impressive clinical activity in this interim assessment of data from these patients with CLL,” said Michael Y. Choi of UC San Diego Moores Cancer Center, and an investigator in the study.

Among 18 patients, Oncternal said the drug was well tolerated, with adverse drug reactions typical of ibrutinib alone.

A separate cohort of the clinical trial treated six patients with mantle cell lymphoma, is rare and aggressive form of non-Hodgkin lymphoma. Data will be presented at a future conference, according to Oncternal.

In March, Oncternal said the merger would provide a $26 million runway. The cash will advance clinical testing, including a planned phase 2 study of cirmtuzumab and ibrutinib. The California Institute for Regenerative Medicine has put in funding for cirmtuzumab, too.

Cirmtuzumab, in combination with the approved drug paclitaxel, is also in a phase 1 trial for women with metastatic breast cancer at UC San Diego. Oncternal’s pipeline also includes TK-216, undergoing a phase 1 trial alone and in combination with vincristine for the rare pediatric cancer Ewing sarcoma.