KaloBios Announces Phase 2 Data For Experimental Cystic Fibrosis Lung Infection Therapy

Daniela Semedo, PhD avatar

by Daniela Semedo, PhD |

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CF antibodies

Staphylococcus Aureus KaloBios Pharmaceuticals, Inc. recently announced data on a Phase 2 randomized double-blind, placebo-controlled trial of KB001-A, an anti-PcrV monoclonal antibody (mAb) fragment, to be used as treatment for Pseudomonas aeruginosa (Pa) lung infections in subjects with cystic fibrosis (CF).

The KB001-A trial enrolled 182 patients with CF who had their lungs colonized with Pa at the start of the study and agreed to take the  antibiotic for at least the preceding two cycles. At week four, their medication was discontinued.

The patients were randomized to either receive treatment with KB001-A intravenously throughout 16 weeks (dosed 10 mg/kg every four weeks with one additional loading dose at Week 2) or placebo. The trial’s primary endpoint was the time needed for antibiotics for respiratory signs and symptoms, expressed as a hazard ratio.

Results from the KaloBios KB001-A showed that the compound was safe with no major tolerance complications. However, the primary endpoint — indication of reduced risk to develop pulmonary exacerbations — was not met. The trial’s secondary endpoints included improvements in FEV1, and subject-reported outcomes (assessed with the Cystic Fibrosis Respiratory Symptom Diary). However, these secondary end-points did not reveal any advantage with the KB001-A, either.

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In a recent news release, Nestor A. Molfino, MD, MSc., KaloBios’ Chief Medical Officer said “The study did demonstrate a non-significant reduction in Pa titer in sputum measured post dosing and a 3% improvement in FEV1 (p=0.0029) at Week 16 for the KB001-A arm compared to placebo; however, these effects were not accompanied by improvements in other clinically significant end-points such as exacerbations or symptoms,” “The KaloBios team is still collecting all of the patient data and working to further understand the results and plan to submit our comprehensive findings to a scientific meeting or journal.”

In the release, David W. Pritchard, KaloBios’ President and Chief Executive Officer said “We are very disappointed that KB001-A did not demonstrate a clinically significant effect on Pa infections in these CF patients, but we are thankful to all of them for volunteering to participate in this study,” “Based on these top line data, we intend to discontinue our development of KB001-A in cystic fibrosis.”

“Going forward, KaloBios will focus resources and efforts on advancing our oncology programs.  Specifically, we are working to advance our KB004 oncology program as well as to expand the oncology development portfolio with the possible introduction of additional oncology indications for KB004 or for KB003, our anti-GM-CSF antibody. Currently, the KB004 Phase 2 cohort expansion study evaluating subjects with myelofibrosis, myelodysplastic syndrome, and acute myeloid leukemia is actively enrolling,” Mr. Pritchard clarified.

KaloBios Pharmaceuticals, Inc. is conducting other trials with first-in-class monoclonal antibodies aimed to treat severe life threatening or incapacitating conditions with a special focus on cancer.