On September 9, 2020 – Abbisko Therapeutics, a clinical-stage biopharmaceutical company, announced that it has received IND approval for phase Ib/II clinical trial of Mavorixafor, a CXCR4 antagonist, in combination with Toripalimab in patients with triple negative breast cancer (TNBC) in China. The study will explore the tolerability, safety and preliminary efficacy of this combination therapy in TNBC subjects at locally advanced or metastatic stage.

Mavorixafor, developed by X4 Pharmaceutials, is a "first-in-class" oral CXCR4 antagonist that is currently being studied in a global Phase 3 trial in WHIM syndrome and two Phase 1b studies – in combination with ibrutinib in patients with Waldenström’s macroglobulinemia, and as a monotherapy in patients with severe congenital neutropenia (SCN). Promising safety and efficacy data have been recognized by the US FDA and led to a Breakthrough Therapy Designation. It also received Orphan Drug Designations in both the US and EU.

As the strategic partner, Abbisko Therapeutics will focus on exploring the therapeutic potential of Mavorixafor in immune-oncology in China. Emerging evidence from early clinical studies have demonstrated that blocking CXCR4 alters the tumor microenvironment, promotes T cell infiltration, and leads to increase of CD8+ T cell number and activity in tumor.