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| Primary information |
|---|
| ID | 13908 |
| Therapeutic ID | Th1445 |
| Protein Name | Ocrelizumab |
| Sequence | NA
|
| Molecular Weight | 145000 |
| Chemical Formula | C6494H9978N1718O2014S46 |
| Isoelectric Point | NA |
| Hydrophobicity | NA |
| Melting point | NA |
| Half-life | The terminal elimination half-life was 26 days [FDA Label]. |
| Description | Ocrelizumab is a CD20-directed cytolytic antibody indicated for the treatment of patients with relapsing or primary progressive forms of multiple sclerosis. It is a second-generation recombinant humanized monoclonal IgG1 antibody that selectively targets the B lymphocytes that express the CD20 antigen. As a humanized molecule, ocrelizumab is expected to be less immunogenic with repeated infusions which improves the benefit-to-risk profile for patients with relapsing or progressive forms of MS. Multiple sclerosis (MS) is a chronic, inflammatory, autoimmune disease of the central nervous system that leads to neurological disabilities and significantly reduced quality of life [L1199]. Most patients with MS experience episodes of relapses with worsening function, followed by recovery periods, or remissions. Primary progressive multiple sclerosis (PPMS) accounts for 10-15% of the overall population of patients with MS, and involves gradual worsening of neurologic disability from symptom onset, often without early relapses or remissions [A31741]. Developed by Genentech/Roche, ocrelizumab was approved by the FDA in March 2017 under the market name Ocrevustm for intravenous injection. It was later approved by Health Canada (as Ocrevus) in August 2017, making the drug the first available treatment for PPMS in both U.S. and Canada. In clinical trials of patients with relapsing forms of MS, treatment with ocrelizumab resulted in reduced relapse rates and reduced worsening of disability compared to interferon beta-1a [L1199]. In phase 3 clinical trials of patients with PPMS, treatment with ocrelizumab demonstrated lower rates of clinical and MRI progression than placebo [A31741]. |
| Indication/Disease | Indicated for the treatment of adult patients with relapsing or primary progressive forms of multiple sclerosis [FDA Label]. |
| Pharmacodynamics | Since ocrelizumab interferes with the CD20 assay, CD19+B-cells were used to assess B-cell counts after ocrelizumab treatment. 14 days following infusion, a reduction in CD19+B-cell counts was observed. In clinical studies, B-cell counts rose to above the lower limit of normal (LLN) or above baseline counts between infusions of ocrelizumab at least one time in 0.3% to 4.1% of patients. In a clinical study involving 51 patients, the time for B-cell counts to return to baseline or LLN was ranged from 27 to 125 weeks, with the median time of 72 weeks, after the last infusion. Within 2.5 years after the last infusion, B-cell counts returned to either baseline or LNN in 90% of the patients [FDA Label]. |
| Mechanism of Action | B lymphocytes are known to contribute to the pathogenesis of MS through activation of pro-inflammatory T cells and secretion of proinflammatory cytokines. B cells may differentiate into plasma cells that can produce autoantibodies directed against myelin and cause complement-mediated attack on the myelin sheath [A31739]. CD20 is a cell-surface antigen found on pre-B cells, naïve and mature B cells and memory B cells. However, this activated glycosylated phosphoprotein is not expressed on haematopoietic stem cells, pro-B cells (precursors), or differentiated plasma cells [A31739, A31741]. While the exact mechanism of ocrelizumab leading to B-cell depletion is unknown, there are several different proposed mechanisms. Upon cell surface binding to CD20-expressing B lymphocytes, ocrelizumab promotes antibody-dependent cellular cytotoxicity and complement-mediated cell lysis. The capacity for B-cell reconstitution and preexisting humoral immunity is preserved [A31741], such as levels of IgG and IgM antibodies in the blood of cerebrospinal fluid. Ocrelizumab may induce antibody-dependant cellular cytotoxicity involving macrophages, natural killer cells, and cytotoxic T cells that act together to cause cell death [A31739]. Another mechanism is apoptosis, which may result from cross-linking membrane CD20 on the target cell surface [A31739]. |
| Toxicity | Studies assessing the carcinogenicity and mutagenicity of ocrelizumab have not been conducted [FDA Label]. |
| Metabolism | As with other antibodies, ocrelizumab is expected to undergo nonspecific catabolism and broken into smaller peptides and amino acids [FDA Label]. |
| Absorption | Ocrelizumab displays a two-compartment pharmacokinetic model with time-dependent clearance. The overall exposure at the steady-state (AUC over the 24 week dosing intervals) of ocrelizumab was 3,510 mcg/mL per day. Following intravenous infusion of maintenance doses of 600 mg every 6 months in relapsing MS patients, the mean peak plasma concentration (Cmax) was 212 mcg/mL. Following intravenous infusion of two 300 mg doses separated by 14 days every 6 months in patients with PPMS, Cmax was reported to be 141 mcg/mL. The pharmacokinetics of ocrelizumab was essentially linear and dose proportional between 400 mg and 2000 mg [FDA Label]. |
| Central volume of distribution was 2.78 L [FDA Label]. |
| Clearance | Constant clearance was estimated at 0.17 L/day, and initial time-dependent clearance at 0.05 L/day. Peripheral volume and inter-compartment clearance were estimated at 2.68 L and 0.29 L/day, respectively [FDA Label]. |
| Categories | Selective Immunosuppressants |
| Patents Number | NA |
| Date of Issue | NA |
| Date of Expiry | NA |
| Drug Interaction | NA |
| Target | B-lymphocyte antigen CD20 |
| Brand Name | NA |
| Company | NA |
| Brand Description | NA |
| Prescribed For | NA |
| Chemical Name | NA |
| Formulation | NA |
| Physical Appearance | NA |
| Route of Administration | NA |
| Recommended Dosage | NA |
| Contraindication | NA |
| Side Effects | NA |
| Useful Link 1 | Link |
| Useful Link 2 | NA |
| Remarks | NA |