ContraFect Corporation announced positive topline results from its Phase 2 clinical trial of exebacase (CF-301) for the treatment of Staphylococcus aureus (Staph aureus) bacteremia including endocarditis. Overall, exebacase, used in addition to standard of care (SOC) antibiotics, achieved clinically meaningful improvement in the primary efficacy endpoint of clinical response at Day 14 as demonstrated by a 70.4% responder rate as compared to a 60.0% responder rate among patients treated with antibiotics alone. Higher responder rates at Day 14 were also seen with exebacase compared to antibiotics alone in pre-specified exploratory analyses in methicillin-resistant Staph aureus (MRSA) patients (p=0.010) and in patients diagnosed with Staph aureus bacteremia alone (p=0.035) as well as in the subgroup of patients with Staph aureus bacteremia including right-sided endocarditis (p=0.028). The company believes these results represent a positive signal of efficacy, particularly in view of the heterogeneous patient population and an unexpected imbalance in the distribution of difficult-to-treat left-sided endocarditis in favor of the placebo group. Exebacase demonstrated a robust safety and tolerability profile in this first Phase 2 study of patients treated with lysin therapy which is complimentary to, and synergistic with, conventional antibiotics. The Phase 2 clinical trial of exebacase is an international, multi-center, randomized, double-blind, placebo-controlled clinical trial in patients with Staph aureus bacteremia including endocarditis. This superiority design study compared the responder rates with exebacase administered on a background of antibiotic therapy to antibiotics alone. The primary efficacy parameter was clinical response at Day 14 and the data readout of the core study was 28 days after end of antibiotic therapy in all patients. Long-term follow-up is ongoing and will be completed 180 days after all patients were dosed with study drug. One hundred and sixteen patients enrolled in the study had confirmed Staph aureus bacteremia/endocarditis and received study drug. These 116 patients constituted the microbiological intent to treat (mITT) population, which was the primary efficacy analysis population. A total of 38.8% of exebacase-treated and 35.5% of placebo patients, respectively, had a MRSA infection. The majority of patients in both treatment groups had bacteremia (77.5% of the exebacase group and 86.7% of the placebo group). However, there was an unequal distribution of patients with left-sided endocarditis between the treatment groups. A total 15.5% of exebacase-treated patients had left-sided endocarditis compared to 6.7% of placebo patients. The clinical responder rates on Day 14 in the subset of patients with bacteremia including right-sided endocarditis treated with exebacase was 80.0% compared to 59.5% in the patients treated with antibiotics alone, a 20.5% improvement (p=0.028). In patients diagnosed with Staph aureus bacteremia alone, the clinical responder rate on Day 14 in the exebacase-treated group was 81.8% compared to 61.5% in the patients treated with antibiotics alone (p=0.035). Of note, among all patients infected with MRSA, a 42.8% higher responder rate was observed in exebacase-treated patients compared to those treated with antibiotics alone (74.1% compared to 31.3%, respectively (p=0.010)). Based on these data, the company concludes that in this trial exebacase demonstrated clinically meaningful improvements in outcomes compared to antibiotic therapy alone. The incidence of treatment emergent adverse events (TEAEs) was balanced between the treatment groups (88.9% and 85.1% of the exebacase and placebo groups, respectively), with incidence rates as expected for this population, given the severity of the disease under study and that patients had multiple co-morbidities. The incidence rates of TEAEs reported within approximately one week after administration of the single dose of study drug were balanced between the treatment groups (66.7% and 66.0% in the exebacase and placebo groups, respectively). The overall rate of serious TEAEs was also similar between the treatment groups (47.2% for exebacase and 51.1% for placebo). Among all patients who received study drug, 19.4% of exebacase patients and 14.9% of placebo patients died. There were no serious TEAEs that the company determined to be related to exebacase. Importantly, there were no reports of hypersensitivity to exebacase and no patients discontinued study drug in either treatment group. Based on these data the company concludes that exebacase was safe and well-tolerated in this study.