I-Mab has reported positive top-line findings from the Phase II clinical trial of lemzoparlimab (TJC4) plus azacitidine (AZA) in recently diagnosed, higher risk myelodysplastic syndrome (HR-MDS) patients.

The open-label trial analysed the safety and efficacy of lemzoparlimab plus AZA in such patients. 

Until 31 March this year, the trial enrolled 53 subjects who were given 30mg/kg intravenous (IV) doses of lemzoparlimab every week and 75mg/m² subcutaneous (SC) doses of AZA on days one to seven in a cycle of 28 days.

According to the trial findings, the overall response rate (ORR) and complete response rate (CRR) were found to be 86.7% and 40%, respectively, in subjects who began treatments six months or more before the assessment.

For subjects who started treatment four months or longer before the assessment, the ORR and CRR were reported to be 86.2% and 31%, respectively. 

In the trial, the lemzoparlimab and AZA combination was found to be well-tolerated, with the safety profile in line with AZA monotherapy.

In addition, 31% of the 29 subjects who required blood transfusions at baseline were independent of them during analysis. 

Most subjects with CR showed to have a reduction in the variant allele frequency (VAF) of MDS-related gene mutation including TP53, TET2, and RUNX1.

The latest results are in line with lemzoparlimab’s anti-leukemic activities and anticipated drug safety.

A new CD47 antibody, lemzoparlimab acts on tumour cells with a reduced untoward effect on red blood cells.

I-Mab president Dr Andrew Zhu said: “The Phase II clinical data demonstrated a good safety profile, along with promising efficacy, and underscored I-Mab’s commitment to bring transformational therapies to patients in need. 

“These results warrant our focused efforts to advance lemzoparlimab towards initiation of a Phase III registrational trial.”

In July this year, the company dosed the first subject in China in a Phase I trial of TJ-CD4B (ABL111), for solid tumour patients.