Oncternal Therapeutics Announces Presentation of Clinical Data Update on Cirmtuzumab in Combination with Ibrutinib at 2019 ASH Annual Meeting

Oncternal Therapeutics, Inc. (Nasdaq: ONCT), a clinical-stage biopharmaceutical company focused on the development of novel oncology therapies, today announced the presentation of updated interim clinical data from the ongoing Phase 1/2 CIRLL (Cirmtuzumab and Ibrutinib targeting ROR1 for Leukemia and Lymphoma) clinical trial, in which cirmtuzumab, an investigational anti-ROR1 monoclonal antibody, is being evaluated in combination with ibrutinib in patients with chronic lymphocytic leukemia (CLL) or mantle cell lymphoma (MCL). The results were presented at the American Society of Hematology (ASH) Annual Meeting in Orlando. A copy of the poster presentation is available online at www.oncternal.com.

Thirty-four patients with CLL who had never been treated with a BTK inhibitor were enrolled in the dose-finding and dose-confirming cohorts of this clinical trial, including 12 treatment-naïve and 22 relapsed/refractory patients, and all 34 were evaluable for efficacy. As of the data cut-off in early November 2019,

• Twenty-nine of the 34 patients achieved a response, for an overall best objective response rate of 85%.
• One patient achieved a complete response (CR) and remained in remission six months after completion of the trial and discontinuation of all anti-CLL therapy. In addition, three patients met radiographic and hematologic response criteria for Clinical CR, bone marrow biopsy not performed but pending.
• Five patients had stable disease.
• The total clinical benefit rate was 100%.
• None of the patients progressed or died, for a progression-free survival (PFS) of 100% with a median follow-up of 7.4 months.
• Patients achieved responses rapidly, with 68% of patients achieving a clinical response by three months on combination therapy.
• The rise in leukemic cell counts that is typically seen in the first six months with ibrutinib monotherapy was blunted with the cirmtuzumab plus ibrutinib combination, and leukemic cell counts returned toward baseline and normal levels rapidly.

Twelve patients with relapsed/refractory MCL, eight of whom were evaluable for efficacy, were enrolled in the dose-finding cohort of this trial. As of the data cut-off, five of the eight evaluable patients had achieved a clinical response, for an overall best objective response rate of 63% at a median follow-up of six months. Two patients with aggressive or bulky and heavily pre-treated MCL achieved CR, the longest of which is continuing with the patient on study for over 17 months. In addition, three patients had stable disease, for a total clinical benefit rate of 100%.