Mosunetuzumab Bispecific Antibody in Resistant non-Hodgkin lymphoma
by Dr. C.H. Weaver M.D. 12/2019
Mosunetuzumab, a new immunotherapy in development is capable of inducing complete remissions in patients with refractory or resistant non-Hodgkin lymphoma (NHL) including patients that have failed multiple therapies, stem cell transplantation or CAR T cell therapy. Despite recent advances in the treatment of NHL some patients still succumb to NHL and new treatments are needed.
Mosunetuzumab is an investigational CD20-CD3 T-cell engaging bispecific antibodies. Mosunetuzumab was designed to target the CD20 antigen on the surface of B-cells and the CD3 antigen on the surface of T-cells. This dual targeting activates and redirects a lymphoma patient’s existing T-cells to engage and eliminate lymphoma targeted B-cells by releasing cytotoxic proteins into the B-cells.
About the GO29781 Clinical Trial
The GO29781 clinical trial [NCT02500407] is a Phase I/Ib, multi-center, open-label, dose-escalation study designed to evaluate the safety of mosunetuzumab and determine optimal dosing in people with relapsed or refractory B-cell NHL. The clinical trial has evaluated over 270 patients with refractory or resistant NHL, including patients who had relapsed following, or are resistant to CAR T-cell therapy.
Mosunetuzumab trial summary results are very exciting;
- Objective response rate of 63% in slow-growing NHL including a 43% complete remission rate with 83% of patients with slow-growing NHL remaining in remission up to 26 months off initial treatment
- Objective response rate of 37% in aggressive NHL including a 19% complete response rate with 71% of patients remaining in remission up to 16 months off initial treatment.
- Objective response rate of 39% in CAR T cell therapy failures including a 22% complete response rate. In some patients molecular testing showed that the CAR T cells increased in number following treatment suggesting that mosunetuzumab may boost the effect of CAR treatment.
- Notable side effects include cytokine release syndrome (CRS) in 29% and neurological adverse events occurred in 4% percent of patients. Only 3% required treatment of CRS with Actemra (tocilizumab).
Mosunetuzumab is currently only available in ongoing clinical trials and must still undergo approval by the FDA. Patients with resistant or refractory NHL may want to follow its development as it appears to represent a significant treatment advance.
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