MABp1, a first-in-class true human antibody targeting interleukin-1α in refractory cancers: an open-label, phase 1 dose-escalation and expansion study

Background: Inflammation is an important feature of the malignant phenotype and promotes angiogenesis, tumour invasiveness, metastases, and cachexia. We used a first-in-class, monoclonal antibody (MABp1) cloned from a human being to target interleukin-1α, a mediator of chronic inflammation. We aimed to assess the safety and tolerability of MABp1 for interleukin-1α blockade in a refractory cancer population.

Methods: We did an open-label, dose-escalation, and phase 1 study of MABp1 in adults with metastatic cancer at the MD Anderson Clinical Center for Targeted Therapy (Houston, TX, USA). We used a standard 3+3 design to identify the maximum tolerated dose. Patients received MABp1 intravenously once every 3 weeks through four dose levels: 0.25 mg/kg, 0.75 mg/kg, 1.25 mg/kg, and 3.75 mg/kg. After the dose-escalation phase, a second dosing arm was started with dosing every 2 weeks at the maximum tolerated dose. The primary objectives were safety, tolerability, characterisation of the pharmacokinetic profile, and identification of the recommended phase 2 dose. Secondary endpoints included pharmacodynamic effects and antitumour activity. All patients who received at least one dose of MABp1 were included in the safety analyses. This trial is registered with ClinicalTrials.gov, NCT01021072.

Findings: Between March 15, 2010, and July 30, 2012, 52 patients with metastatic cancer (18 tumour types) received anti-interleukin-1α monotherapy in dose-escalation and expansion groups. MABp1 was well tolerated, with no dose-limiting toxicities or immunogenicity. Thus, the recommended phase 2 dose was concluded to be 3.75 mg/kg every 2 weeks. Pharmacokinetic data were consistent at all dose levels and showed no evidence of accumulation or increased clearance of MABp1 at increasing doses. For 42 assessable patients, median plasma interleukin-6 concentrations had decreased from baseline to week 8 by a median of 2.7 pg/mL (IQR -12.6 to 3.0; p=0.08). Of the 34 patients restaged, one patient had a partial response and ten had stable disease. 30 patients were assessable for change in lean body mass, which increased by a mean of 1.02 kg (SD 2.24; p=0.02) between baseline and week 8. The most common adverse events possibly related to the study drug were proteinuria (n=11; 21%), nausea (7; 13%), and fatigue (7; 13%). The most frequent grade 3-4 adverse events (regardless of relation to treatment) were fatigue (3; 6%), dyspnoea (2; 4%), and headache (2; 4%). Two patients (4%) had grade 5 events (death due to disease progression), which were unrelated to treatment.

Interpretation: MABp1 was well tolerated, no dose-limiting toxicities were experienced in this study, and disease control was observed. Further study of MABp1 anti-interleukin-1α antibody therapy for advanced stage cancer is warranted.