US-based Cleave Biosciences has initiated an open-label, dose escalation/dose expansion Phase I clinical trial of its lead drug candidate, CB-5083, to treat patients with relapsed and refractory multiple myeloma.
The trial is designed to evaluate the safety, pharmacokinetics, pharmacodynamics and anti-tumour activity of CB-5083 in multiple myeloma patients who have relapsed/refractory or refractory disease after receiving two or more lines of therapy, including an immunomodulatory agent (IMiD) and a proteasome inhibitor.
Around 60 patients are expected to be enrolled in the trial at multiple US cancer centres that are part of the Multiple Myeloma Research Consortium.
CB-5083 is a potent, specific and orally bioavailable inhibitor of p97, a major enzyme through which several aspects of protein homeostasis can be controlled.
Cleave Biosciences chief executive officer Laura Shawver said: "Patients with multiple myeloma whose disease is resistant to existing therapies have run out of options.
"We are eager to assess CB-5083 in this trial and to further understand which tumours are dependent on the p97 pathway for their growth and survival so we can focus our future clinical programme on the patients most likely to benefit from this potential treatment."
The company has discovered CB-5083 through a targeted screening and medicinal chemistry effort.
Anti-tumour activity for CB-5083 has been characterised in vivo in tumour-bearing mice.
According to the company, CB-5083 has robust activity in multiple haematological models as well as in solid tumour xenograft models that are resistant to proteasome inhibitors.
Winship Cancer Institute of Emory University director of Translational Research, B-cell Malignancy Program and professor of Hematology and Medical Oncology Sagar Lonial said: "Targeting protein homeostasis is a well-established approach for the treatment of patients with multiple myeloma, but eventually many patients relapse or no longer respond to therapy.
"By disrupting protein homeostasis using a completely novel target, we hope to validate CB-5083's mechanism and establish its path forward for patients with myeloma."
The preclinical trials have showed significant promise for CB-5083 in solid tumours.
Currently, the company is planning to begin a Phase I trial in solid tumours later this year.
Image: Micrograph of a plasmacytoma, the histologic correlate of multiple myeloma. Photo: courtesy of Nephron.