Galecto, Inc. announced positive topline results from a Phase 2a trial of GB2064 for the treatment of myelofibrosis. The MYLOX-1 trial dosed a total of 18 myelofibrosis patients, of which 11 (61%) patients had previously received janus kinase inhibitor (JAKi) therapy with ruxolitinib, with eight of those patients being refractory and three being intolerant to JAKi therapy. Six out of ten evaluable myelofibrosis patients who received GB2064 monotherapy for at least six months experienced a = 1-grade reduction in collagen fibrosis of the bone marrow, an improvement suggesting that GB2064 could impact the progression of the disease and be disease-modifying.

Fibrosis is a key disease mechanism of myelofibrosis that destroys bone marrow function. Reducing fibrosis is required to slow the progression of the disease. Bone marrow biopsies taken during the study showed that GB2064 penetrated the bone marrow and could exert its anti-fibrotic effect directly in the disease compartment.

Furthermore, GB2064 demonstrated target engagement systemically by binding to LOXL2 in plasma. All six patients who experienced a > 1-grade reduction in bone marrow fibrosis score also showed stable hematological parameters, including hemoglobin, white blood cell count and platelets. At six months of treatment, one patient obtained a =35% reduction in spleen volume, two patients reduced their Total Symptom Score (TSS) by more than 50% and one patient had an anemia response.

Four of these patients have entered the extension phase of the study due to the clinical benefit derived from GB2064 as evaluated by the treating physician, with one patient receiving treatment for more than 30 months. GB2064 showed a generally acceptable tolerability profile in the MYLOX-1 trial. Eighteen patients were dosed with GB2064 monotherapy in the MYLOX-1 trial.

Eight patients completed treatment in the core phase of the MYLOX-1 trial and ten patients discontinued treatment due to an adverse event or disease progression. The most commonly observed treatment-related adverse events were gastrointestinal in nature and were manageable in most patients with standard therapy. The only treatment-related serious adverse event was a case of fall, which was assessed as possibly related to GB2064 by the investigator.