based on results from an ongoing phase 1 trial.
“We assessed feasibility of monthly subcutaneous administration of PF-06801591, a humanized immunoglobulin G4 monoclonal antibody that binds to the programmed cell death [PD-1] receptor,”of the Sarah Cannon Research Institute, Nashville, Tenn., and colleagues wrote in . “Subcutaneous administration of an anti-PD-1 antibody in patients with advanced solid tumors appears to be feasible.”
The researchers evaluated the efficacy, safety, and pharmacokinetics of the novel anti-PD-1 therapy in a group of 40 patients with locally advanced or metastatic solid tumors. The antibody was administered in both subcutaneous and intravenous forms.
Study participants were administered the subcutaneous form of the antibody at 300 mg every 4 weeks or the intravenous form at 0.5, 1, 3, or 10 mg/kg every 3 weeks.
“Dose escalation occurred after two to four patients were enrolled per dose level, with additional patients enrolled in each cohort for further assessment,” the researchers wrote.
The primary endpoints were safety and dose-limiting adverse effects. Efficacy, immunogenicity, pharmacokinetics, and PD-1 receptor occupancy were secondary endpoints.
After analysis, Dr. Johnson and colleagues reported that the overall response rate was 18.4%. In addition, no dose-limiting toxicities were detected in both intravenous and subcutaneous groups, but grade 3 or greater adverse events were reported in 6.7% and 16% of patients treated with subcutaneous and intravenous dosage forms, respectively.
“No dose–adverse event associations were observed during intravenous dose escalation, and no serious skin toxic effects occurred with subcutaneous delivery,” they reported.
Based on the findings, the team selected the subcutaneous form (300 mg) of the therapy for additional assessment in the second half of this ongoing trial.
The study was funded by Pfizer. The authors reported financial affiliations with BerGenBio, EMD Serono, Janssen, Mirati Therapeutics, Pfizer, and several others.
SOURCE: Johnson ML et al. JAMA Oncol. 2019 May 30. .