Ocrevus & Ocrevus Zunovo
Indications
Ocrelizumab is a B-cell-depleting therapy used in adults with multiple sclerosis. The intravenous formulation (Ocrevus) was first approved by the FDA on 28 March 2017. The subcutaneous co-formulation with hyaluronidase (Ocrevus Zunovo) received FDA approval on 13 September 2024. Ocrelizumab is the first and only disease-modifying therapy approved for primary progressive multiple sclerosis (PPMS) and is a high-efficacy option for relapsing forms of MS, where pivotal trials demonstrated superior reduction in annualised relapse rate and disability progression compared with subcutaneous interferon beta-1a.
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Relapsing forms of multiple sclerosis (RMS) — including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease | Adults | Monotherapy | FDA Approved |
| Primary progressive multiple sclerosis (PPMS) | Adults | Monotherapy | FDA Approved |
Ocrelizumab is approved as monotherapy and is not used in combination with other DMTs. Because it produces sustained B-cell depletion, switching to or from other immunomodulators requires careful consideration of washout periods, prior immunosuppressant exposure, and infection risk.
Neuromyelitis optica spectrum disorder (NMOSD), AQP4-IgG seropositive — anti-CD20 therapy is sometimes used when approved agents (eculizumab, satralizumab, inebilizumab) are unavailable or cost-prohibitive. Evidence quality: low (small case series; rituximab data extrapolated).
MOG antibody-associated disease (MOGAD) — used in relapsing disease when first-line therapies fail. Evidence quality: very low (retrospective case series).
Refractory autoimmune encephalitis — occasional use as a B-cell-depleting strategy when rituximab is contraindicated. Evidence quality: very low (case reports).
Off-label use should follow shared decision-making and ideally be coordinated through neuroimmunology specialists.
Dosing
Ocrelizumab follows a fixed dose-by-scenario schedule rather than weight-based dosing. The hallmark of therapy is a six-monthly maintenance interval that aligns with the kinetics of B-cell repopulation. All infusions and injections require pre-medication to attenuate infusion or injection reactions, but the recommended pre-medication regimens differ between the intravenous and subcutaneous formulations.
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum per Cycle | Notes |
|---|---|---|---|---|
| RMS or PPMS — first treatment course (IV) | 300 mg IV on Day 1, then 300 mg IV on Day 15 | — | 600 mg total (split dose) | Initial split dose lowers risk of infusion reaction with first exposure Each 300 mg infusion runs over at least 2.5 h: start at 30 mL/h, titrate by 30 mL/h every 30 min to a maximum of 180 mL/h |
| RMS or PPMS — maintenance (IV, standard) | — | 600 mg IV every 6 months | 600 mg per cycle | Standard infusion runs at least 3.5 h: start at 40 mL/h, titrate by 40 mL/h every 30 min to a maximum of 200 mL/h First maintenance dose 6 months after Day 1; subsequent doses no sooner than 5 months apart |
| RMS or PPMS — maintenance (IV, shorter infusion) | — | 600 mg IV over ~2 hours | 600 mg per cycle | Approved option for patients who tolerated previous infusions without serious reactions |
| RMS or PPMS — Ocrevus Zunovo (SC) | — | 920 mg SC every 6 months | 920 mg per cycle | Single 23 mL injection into the abdomen only, delivered over approximately 10 minutes May be initiated as the first dose or used after switching from IV; contains 23,000 units of recombinant human hyaluronidase (PH20). Doses must be separated by at least 5 months |
| Missed dose | — | Administer as soon as possible; do not wait for the next planned cycle | — | Reset the schedule from the rescheduled dose Do not double-dose |
Pre-medication — IV Ocrevus
- Methylprednisolone 100 mg IV (or an equivalent corticosteroid) approximately 30 minutes before each infusion.
- Antihistamine (e.g., diphenhydramine) approximately 30–60 minutes before each infusion.
- Antipyretic (e.g., paracetamol/acetaminophen) may be added at the prescriber’s discretion.
Pre-medication — Ocrevus Zunovo (SC)
- Oral dexamethasone (or an equivalent corticosteroid) at least 30 minutes before each injection.
- Oral antihistamine (e.g., desloratadine) at least 30 minutes before each injection.
- Antipyretic (e.g., acetaminophen) may be added at the prescriber’s discretion.
Patient Observation Period
- IV infusion: observe for at least 1 hour after each infusion completes.
- SC injection (Ocrevus Zunovo): observe for at least 1 hour after the first injection; observe for at least 15 minutes after each subsequent injection.
Dose Modification for Infusion or Injection Reactions
- Mild–moderate IV reaction: reduce the infusion rate to half the rate at onset; resume only after symptoms resolve.
- Less severe SC reaction: interrupt the injection immediately; complete the dose at the prescriber’s discretion only after symptoms resolve.
- Severe reaction (any route): immediately interrupt and manage with steroids, antihistamines, bronchodilators, or epinephrine as clinically indicated.
- Life-threatening reaction: permanent discontinuation. Future ocrelizumab is contraindicated.
Special Populations
- Renal impairment: mild impairment was represented in clinical trials with no significant change in pharmacokinetics; monoclonal antibodies are not renally cleared.
- Hepatic impairment: mild impairment was represented in clinical trials with no significant change in pharmacokinetics; moderate-to-severe impairment has not been studied.
- Elderly (≥55 years): data are limited; pivotal trials enrolled few patients above 55. Use the standard dose with heightened infection vigilance.
- Pregnancy: avoid conception during therapy and for at least 6 months after the last dose. If pregnancy occurs, weigh continuation against MS disease activity in consultation with maternal-fetal medicine.
- Paediatric patients: safety and efficacy in patients under 18 years have not been established; ocrelizumab is not currently approved for paediatric MS.
Per the prescribing information, complete required live or live-attenuated vaccinations at least 4 weeks before initiating ocrelizumab and complete non-live vaccinations at least 2 weeks before initiation when possible. Live attenuated vaccines must be avoided during therapy and until B-cell recovery. After ocrelizumab is started, B-cell-dependent vaccine responses are markedly attenuated, so timing inactivated booster vaccines toward the end of the dosing interval (when B-cell counts are partially recovering) is a pragmatic option in selected patients. The median time to peripheral B-cell repopulation to baseline or the lower limit of normal in clinical studies was approximately 72 weeks (range 27–175 weeks) after the last dose.
Pharmacology
Mechanism of Action
Ocrelizumab is a recombinant humanised IgG1 monoclonal antibody engineered to bind the CD20 antigen, a transmembrane phosphoprotein found on pre-B and mature B lymphocytes. CD20 is absent from haematopoietic stem cells, pro-B cells, and terminally differentiated plasma cells, which preserves long-term humoral immunity and the capacity to regenerate the B-cell pool after therapy ends.
Once bound, ocrelizumab depletes CD20-positive B cells through three complementary effector mechanisms: antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity. The clinical benefit in multiple sclerosis is thought to reflect interruption of B-cell-driven antigen presentation, cytokine signalling, and aberrant lymphoid follicle formation in the meninges, rather than direct effects on antibody production. Peripheral CD19+ B-cell counts (used as a surrogate marker because the drug interferes with the CD20 assay) fall within 14 days of the first dose and remain suppressed for the duration of dosing intervals; T-cell populations are largely preserved, distinguishing ocrelizumab from broader immunosuppressants.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | IV: 100% bioavailable. SC (Ocrevus Zunovo): estimated absolute bioavailability approximately 81%; mean Cmax 132 µg/mL reached at approximately 4 days post-injection. With IV: mean Cmax 212 µg/mL (600 mg) and 141 µg/mL (initial 2 × 300 mg) | SC formulation provides comparable systemic exposure with shorter administration time; useful for outpatients and where venous access is poor |
| Distribution | Central volume of distribution 2.78 L; peripheral volume 2.68 L; intercompartment clearance ~0.29 L/day. Largely confined to extracellular fluid; placental transfer occurs via Fc-mediated transport, especially in the third trimester | Negligible CNS penetration limits direct effects on CNS-resident B cells; placental transfer mandates planned conception and contraception counselling |
| Metabolism | Catabolised to small peptides and amino acids via the reticuloendothelial system; no hepatic CYP450 metabolism. PK is essentially linear and dose-proportional between 400 mg and 2,000 mg | No CYP-mediated drug interactions; pharmacokinetics is not affected by drugs altering hepatic enzymes |
| Elimination | Constant clearance 0.17 L/day; initial time-dependent clearance 0.05 L/day declining with a half-life of 33 weeks. Terminal elimination half-life is 26 days for IV and 20 days for SC; no renal excretion | Sustained B-cell depletion supports the 6-month dosing interval; immunosuppressive effects persist for months after the last dose, relevant for vaccination, pregnancy planning, and switching DMTs |
Population pharmacokinetic analyses identified body weight as the main covariate affecting clearance, but the effect size is small enough that fixed dosing achieves acceptable exposure across the licensed weight range. Anti-drug antibodies have been detected at very low frequency and have not been associated with reduced efficacy or increased reactions.
Side Effects
The safety profile of ocrelizumab is dominated by infusion-related (or injection-related) reactions and increased rates of common infections, particularly upper respiratory tract infections. Frequencies below are drawn from the OPERA I, OPERA II, ORATORIO, and OCARINA II trials and the integrated FDA prescribing information for Ocrevus and Ocrevus Zunovo.
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Upper respiratory tract infection | ~40% (RMS); ~49% (PPMS) | Higher rate in the PPMS cohort; usually mild and self-limited |
| Infusion reactions (RMS, pooled OPERA) | 34.3% | Most common with the first infusion (~27% of patients on dose 1); incidence drops with subsequent infusions; pruritus, rash, throat irritation, flushing, tachycardia |
| Infusion reactions (PPMS, ORATORIO) | 39.9% | Slightly higher than RMS; serious IRRs occurred in 0.3% of IV-treated patients |
| Injection reactions (Ocrevus Zunovo, OCARINA II) | ~49% (first injection) | Predominantly local (erythema, pain, swelling, pruritus); incidence of local reactions on injections 2–4 ranged from 31% to 43%; systemic reactions on subsequent injections 3% to 7% |
| Skin and skin-structure infections | ~14% (PPMS) | Cellulitis and folliculitis predominate |
| Decreased serum immunoglobulins (IgG < LLN over multiple cycles) | Cumulative; rises with treatment duration | Pooled long-term data link decreased IgG with increased serious infection rates |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Lower respiratory tract infection (bronchitis, pneumonia) | ~8% (RMS); ~10% (PPMS) | Higher rate in PPMS; assess promptly with imaging if symptoms persist |
| Herpes virus infections (oral, genital, zoster) | 5.9% (RMS pooled) | Typically uncomplicated; treat with standard antivirals; rare severe genital herpes reported |
| Depression | ~8% | Screen with PHQ-9 or similar at follow-up visits; depression is a common comorbidity in MS overall |
| Cough | ~7% | Often part of URI; persistent cough warrants chest imaging |
| Diarrhoea | ~6% | Usually mild and self-limited; new persistent or bloody diarrhoea should prompt evaluation for immune-mediated colitis |
| Pain in extremity | ~5% | Non-specific; consider underlying neuropathic cause |
| Peripheral oedema | ~4% | Generally mild |
| Back pain (PPMS) | ~14% | Often reflects underlying disease; consider non-pharmacological management |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Severe / life-threatening infusion reaction (anaphylaxis, bronchospasm, hypotension) | 0.3% of IV-treated patients | Within minutes of infusion start; usually first dose | Stop infusion immediately; manage anaphylaxis (epinephrine, steroids, fluids); permanent discontinuation |
| Progressive multifocal leukoencephalopathy (PML) | Rare (post-marketing) | Months to years; higher risk with prior natalizumab or other immunosuppressant exposure | Hold drug for any new neurological deficit; obtain MRI and CSF JCV PCR; permanent discontinuation if confirmed |
| Hepatitis B reactivation (including fulminant hepatitis) | Rare | Weeks to months after initiation in HBV carriers or those with resolved infection | Screen all patients before starting (HBsAg, total anti-HBc); consult hepatology for positive results; antiviral prophylaxis often required |
| Serious bacterial, viral, or opportunistic infection | ~1.3% (OPERA RMS); ~6% (ORATORIO PPMS) | Any time during therapy; risk rises with prolonged hypogammaglobulinaemia | Hold further dosing; treat aggressively; monitor IgG and consider IVIG replacement if recurrent |
| Babesiosis | Rare (post-marketing) | Variable; typically following tick exposure | Consider in immunosuppressed patients with febrile illness and haemolysis; thick/thin smear and PCR; treat per ID guidance |
| Immune-mediated colitis | Rare (post-marketing) | Weeks to years from initiation | Refer to gastroenterology for new persistent diarrhoea, abdominal pain, or rectal bleeding; some cases require systemic corticosteroids or surgery |
| Liver injury (without viral hepatitis) | Rare (post-marketing class effect) | Variable | Obtain baseline ALT, AST, alkaline phosphatase, bilirubin; monitor as clinically indicated; investigate fatigue, anorexia, jaundice, dark urine, or right-upper-quadrant pain promptly |
| Hypogammaglobulinaemia with serious infection | Increases with cumulative cycles | Typically after several years of therapy | Monitor IgG, IgM, IgA before each infusion; involve immunology if IgG persistently below normal with recurrent infection |
| Malignancy — breast cancer signal | 6 of 781 ocrelizumab-treated females (controlled trials) vs 0 of 668 in REBIF/placebo | Variable; long-term post-marketing rates remain consistent with background population estimates | Maintain age-appropriate breast cancer screening; report new diagnoses to manufacturer registry |
| Other malignancies (overall) | 0.5% (OPERA pooled, neoplasms); ~0.49 per 100 patient-years (long-term integrated safety) | Variable | Continue routine cancer surveillance per population guidelines |
| Reason for Discontinuation | Incidence | Context |
|---|---|---|
| All-cause AE-driven discontinuation (long-term integrated safety, up to 7 years) | 3.2% (181/5,680 patients) | Pooled across 11 clinical trials (18,218 patient-years); rate stable over time |
| Infusion reaction | ~1% | Almost always after the first or second infusion; rate falls dramatically with subsequent cycles |
| Malignancy (mandatory discontinuation per protocol) | <1% | Includes the breast cancer signal in pivotal trials |
| Serious infection | <1% | Pneumonia or recurrent skin/soft-tissue infection are the most frequent triggers |
| Hypogammaglobulinaemia with infections | <1% | Cumulative effect of multiple cycles; some patients managed with extended dosing intervals rather than discontinuation |
| Patient choice (pregnancy planning, treatment fatigue) | ~1–2% | Long half-life requires planning at least 6 months before conception |
Reactions are most common with the first infusion (approximately 27% of patients in OPERA pooled analysis). Standard pre-medication with IV methylprednisolone, an antihistamine, and (optionally) an antipyretic markedly reduces severity. Serious IV infusion reactions occurred in 0.3% of patients in MS trials; there were no fatal infusion reactions. For mild-to-moderate IV reactions, halve the infusion rate; for severe reactions, interrupt the infusion and resume only after symptoms resolve, then at half the previous rate. Document the reaction characteristics in detail because subsequent cycles often proceed uneventfully once the patient is established.
Drug Interactions
Ocrelizumab is not metabolised by cytochrome P450 enzymes, so classic pharmacokinetic interactions are minimal. The clinically relevant interactions are pharmacodynamic — additive immunosuppression, blunted vaccine responses, and altered infection risk when combined with other immune-modulating agents.
Monitoring
Monitoring focuses on a structured baseline workup before initiation, surveillance for infection and immunoglobulin depletion during therapy, and vigilance for late complications such as malignancy and PML. The current Ocrevus Zunovo prescribing information requires baseline HBV serology, quantitative serum immunoglobulins, and liver function tests (ALT, AST, alkaline phosphatase, bilirubin) before initiation; these expectations apply to the IV formulation as well in clinical practice.
-
Hepatitis B serology
Before first dose
Routine HBsAg and total anti-HBc are mandatory before initiation. Anti-HBs is helpful to confirm prior vaccination response. Patients with active or resolved hepatitis B require hepatology input and often antiviral prophylaxis. -
Quantitative immunoglobulins (IgG, IgM, IgA)
Baseline, then before each infusion or injection
Routine The trend over time is more informative than a single value. IgM falls earliest. Persistent IgG below the lower limit of normal — especially with recurrent infections — prompts immunology referral and consideration of extended dosing intervals or IVIG replacement. -
Liver function tests (ALT, AST, ALP, bilirubin)
Baseline, then as clinically indicated
Routine Required at baseline per the current PI given post-marketing reports of clinically significant liver injury without viral hepatitis on anti-CD20 therapies; investigate fatigue, anorexia, jaundice, or right-upper-quadrant pain promptly. -
CBC with differential
Before each infusion (clinical practice)
Routine Monitor for unexpected cytopenias and lymphopenia. Severe neutropenia (rare) warrants temporary withholding of further dosing. -
Pregnancy testing
Before each infusion in patients of childbearing potential
Routine Effective contraception should be used during therapy and for 6 months after the last dose. Counsel about pregnancy planning at every visit. -
Active infection assessment
Before each dose
Routine Per the PI, determine whether there is an active infection before each dose; delay administration until any active infection has resolved. -
Vital signs during administration
Throughout administration and during the post-dose observation window
Routine Document blood pressure, pulse, oxygen saturation, and any new symptoms. Observe for at least 1 hour after each IV infusion, after the first SC injection, and for at least 15 minutes after subsequent SC injections. -
Infection symptom review
Every visit; safety-net all patients between cycles
Routine Prompt evaluation of fever, productive cough, dysuria, skin breakdown, or persistent diarrhoea. Lower threshold for imaging and cultures than in immunocompetent patients. -
Brain MRI
Annually or per institutional MS protocol
Routine Assess MS disease activity (new T2 or gadolinium-enhancing lesions). New atypical lesions should also raise suspicion for PML and prompt urgent specialist review. -
Cancer screening (age-appropriate, including breast)
Per population-based guidelines
Routine Maintain mammography, cervical screening, and colorectal screening on schedule. The numerical breast cancer signal in pivotal trials warrants reinforcement of screening adherence. -
Hepatitis B PCR / DNA
If anti-HBc positive at baseline
Trigger-based Periodic monitoring (every 3–6 months) is appropriate for patients with prior hepatitis B exposure receiving antiviral prophylaxis. Hepatology should guide frequency. -
CSF JC virus PCR / urgent brain MRI
Any new neurological symptom not attributable to MS
Trigger-based Hold further dosing pending evaluation. PML should be specifically excluded with MRI and CSF testing in patients with prior natalizumab exposure or new atypical white-matter lesions. -
Vaccine antibody titres
After major immunisation events (e.g., hepatitis B series)
Trigger-based Document seroconversion where vaccine response is clinically important (hepatitis B in healthcare workers, travel vaccines). Anticipate reduced response and consider repeat dosing. -
GI evaluation
If new persistent diarrhoea, abdominal pain, or rectal bleeding
Trigger-based Refer to gastroenterology to rule out immune-mediated colitis (now in the PI Warnings and Precautions section based on post-marketing reports).
Contraindications & Cautions
Absolute Contraindications
- Active hepatitis B virus infection — confirmed by positive HBsAg and anti-HBV testing; due to risk of severe reactivation and fulminant hepatitis.
- History of life-threatening hypersensitivity reaction to ocrelizumab or any component of the formulation, including prior anaphylaxis or anaphylactoid response.
- Active malignancy at the time of proposed initiation — defer until oncology clearance.
- Active serious infection — defer until the infection has resolved.
- Confirmed PML — permanent contraindication.
Relative Contraindications (Specialist Input Recommended)
- Resolved hepatitis B infection (HBsAg-negative, anti-HBc positive) — requires hepatology co-management and an antiviral prophylaxis decision.
- Recent natalizumab exposure — JCV antibody index and structured washout planning before switching, given documented PML reports during this transition.
- Significant baseline hypogammaglobulinaemia — immunology assessment to determine an acceptable IgG threshold and the need for replacement therapy.
- Pregnancy or planned conception within 6 months — discuss with maternal-fetal medicine; the long half-life means the drug remains biologically active well into pregnancy if administered shortly before conception.
- History of significant hepatic disease — given post-marketing reports of liver injury on anti-CD20 therapies; obtain baseline LFTs and hepatology input as needed.
- History of inflammatory bowel disease — post-marketing reports of new or worsening colitis on anti-CD20 therapies warrant gastroenterology input.
Use with Caution
- Older adults (≥55 years) — limited trial data; greater absolute infection risk.
- Patients with prior or current chronic infections (HIV, hepatitis C, latent tuberculosis) — screen and manage appropriately before initiation.
- Cardiovascular comorbidity — pre-medication corticosteroids and the infusion-related fluid load may exacerbate uncontrolled hypertension or heart failure.
- Significant respiratory disease — increased vulnerability to lower respiratory tract infections; consider risk-benefit and pulmonary input.
- Patients with poor venous access — the SC formulation (Ocrevus Zunovo) may be preferable.
B-cell-depleting antibodies, including ocrelizumab, can cause hepatitis B virus reactivation in patients with chronic or resolved infection, occasionally resulting in fulminant hepatitis, hepatic failure, and death. All patients must undergo HBV screening (HBsAg and total anti-HBc) before initiation. Patients with positive results require infectious disease or hepatology consultation, and many will need antiviral prophylaxis throughout therapy and for at least 6–12 months after the last dose.
PML, an opportunistic JC virus infection of the brain, has been reported in patients receiving anti-CD20 therapies, including in the post-marketing setting for ocrelizumab. Risk is highest in patients with prior immunosuppressant exposure, especially natalizumab. Hold ocrelizumab and obtain MRI plus CSF JC virus PCR for any new or worsening neurological, cognitive, or behavioural sign that cannot be explained by MS itself. Permanently discontinue if PML is confirmed.
Immune-mediated colitis was added to the prescribing information in August 2022 based on post-marketing reports, some of which required hospitalisation, systemic corticosteroids, or surgical intervention. Clinically significant liver injury without viral hepatitis was added as a class warning for anti-CD20 MS therapies in 2025. Investigate new persistent diarrhoea, abdominal pain, rectal bleeding, jaundice, dark urine, fatigue, anorexia, nausea, or right-upper-quadrant pain promptly with appropriate referral.
Patient Counselling
Purpose of Therapy
Ocrelizumab is a long-acting antibody that lowers the number of B cells, a type of white blood cell that contributes to multiple sclerosis. By depleting these cells, it reduces relapses, slows the progression of disability, and limits the development of new MRI lesions. It does not cure MS, but it offers high-efficacy disease control with infrequent dosing.
How to Take
Treatment begins with two intravenous infusions two weeks apart. After that, a single infusion is given every six months, taking around two to three and a half hours depending on the rate. A subcutaneous version (Ocrevus Zunovo) is available for some patients and takes about ten minutes, given as a single injection into the abdomen. Pre-medication is given before every dose to reduce reactions: with intravenous treatment this is an IV steroid plus an antihistamine; with the subcutaneous injection this is oral steroid and oral antihistamine taken at least 30 minutes before. Patients are observed for at least one hour after each IV infusion and after the first SC injection. Patients should arrive well-hydrated and having eaten, and should have someone available to drive home if they feel drowsy.
Sources
- Genentech, Inc. OCREVUS (ocrelizumab) Prescribing Information. South San Francisco, CA. https://www.gene.com/download/pdf/ocrevus_prescribing.pdf Primary US labelling for the IV formulation; authoritative source for indications, IV dosing, ADME, contraindications, warnings, and adverse reaction tables.
- Genentech, Inc. OCREVUS ZUNOVO (ocrelizumab and hyaluronidase-ocsq) Prescribing Information. South San Francisco, CA. https://www.gene.com/download/pdf/ocrevus_zunovo_prescribing.pdf US labelling for the SC formulation; source for the 920 mg SC dose, abdomen-only injection site, oral pre-medication regimen, ~81% bioavailability, 20-day terminal half-life, and updated colitis and liver injury warnings.
- European Medicines Agency. Ocrevus: EPAR — Product Information. https://www.ema.europa.eu/en/medicines/human/EPAR/ocrevus European Summary of Product Characteristics; cross-checked for any divergence from US labelling on dosing schedule and warnings.
- US Food and Drug Administration. Ocrevus Zunovo (ocrelizumab and hyaluronidase-ocsq) full prescribing information (NDA 761371). 13 September 2024. https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/761371s000lbl.pdf Initial US approval document for the SC formulation; confirms 920 mg SC every 6 months, abdomen-only administration, and pre-medication requirements.
- Hauser SL, Bar-Or A, Comi G, et al. Ocrelizumab versus interferon beta-1a in relapsing multiple sclerosis. N Engl J Med. 2017;376(3):221–234. https://doi.org/10.1056/NEJMoa1601277 OPERA I and OPERA II pivotal trials that established ocrelizumab’s superiority over IFN beta-1a for relapsing MS; primary source for RMS efficacy and adverse event rates.
- Montalban X, Hauser SL, Kappos L, et al. Ocrelizumab versus placebo in primary progressive multiple sclerosis. N Engl J Med. 2017;376(3):209–220. https://doi.org/10.1056/NEJMoa1606468 ORATORIO trial; the first DMT to demonstrate slowing of disability progression in PPMS, supporting the PPMS indication and the malignancy and infection rates discussed.
- Mayer L, Kappos L, Racke MK, et al. Ocrelizumab infusion experience in patients with relapsing and primary progressive multiple sclerosis: results from the phase 3 randomized OPERA I, OPERA II, and ORATORIO studies. Mult Scler Relat Disord. 2019;30:236–243. https://doi.org/10.1016/j.msard.2019.01.044 Pooled IRR analysis providing the 34.3% (RMS) and 39.9% (PPMS) infusion reaction frequencies cited in the side effects section.
- Hauser SL, Kappos L, Arnold DL, et al. Five years of ocrelizumab in relapsing multiple sclerosis: OPERA studies open-label extension. Neurology. 2020;95(13):e1854–e1867. https://doi.org/10.1212/WNL.0000000000010376 Long-term efficacy extension; supports durability of effect on relapses and confirmed disability progression.
- Wolinsky JS, Arnold DL, Brochet B, et al. Long-term follow-up from the ORATORIO trial of ocrelizumab for primary progressive multiple sclerosis: a post-hoc analysis from the ongoing open-label extension of the randomised, placebo-controlled, phase 3 trial. Lancet Neurol. 2020;19(12):998–1009. https://doi.org/10.1016/S1474-4422(20)30342-2 Extension data demonstrating sustained reduction in disability progression in PPMS over 6.5 years.
- Hauser SL, Kappos L, Bar-Or A, et al. Safety of ocrelizumab in patients with relapsing and primary progressive multiple sclerosis. Neurology. 2021;97(16):e1546–e1559. https://doi.org/10.1212/WNL.0000000000012700 Integrated long-term safety analysis through 7 years (5,680 patients, 18,218 patient-years); source for cumulative discontinuation, serious infection, and malignancy rates.
- Newsome SD, Krzystanek E, Selmaj KW, et al. Subcutaneous ocrelizumab in patients with multiple sclerosis: results of the phase 3 OCARINA II study. Neurology. 2025;104(9):e213574. https://doi.org/10.1212/WNL.0000000000213574 Phase 3 PK-bridging trial supporting non-inferiority of 920 mg SC versus 600 mg IV; pivotal evidence behind the Ocrevus Zunovo approval.
- Newsome SD, Goldstick L, Robertson DS, et al. Subcutaneous ocrelizumab in multiple sclerosis: results of the phase 1b OCARINA I study. Ann Clin Transl Neurol. 2024;11(12):3215–3226. https://doi.org/10.1002/acn3.52229 Dose-finding study that selected 920 mg SC as the dose for the phase 3 OCARINA II trial.
- Rae-Grant A, Day GS, Marrie RA, et al. Practice guideline recommendations summary: disease-modifying therapies for adults with multiple sclerosis. Neurology. 2018;90(17):777–788. https://doi.org/10.1212/WNL.0000000000005347 American Academy of Neurology guideline (reaffirmed 2024) positioning ocrelizumab among DMT options for relapsing and progressive disease.
- Montalban X, Gold R, Thompson AJ, et al. ECTRIMS/EAN guideline on the pharmacological treatment of people with multiple sclerosis. Eur J Neurol. 2018;25(2):215–237. https://doi.org/10.1111/ene.13536 European treatment guideline jointly published in Multiple Sclerosis Journal; framework for selecting high-efficacy therapy in active RMS and the only DMT recommendation for PPMS at time of publication.
- National Institute for Health and Care Excellence. Ocrelizumab for treating primary progressive multiple sclerosis (TA585). 12 June 2019. https://www.nice.org.uk/guidance/ta585 UK technology appraisal restricting reimbursed use to early PPMS with imaging features of inflammatory activity; informs the relative contraindication and patient-selection discussion.
- Hauser SL. The Charcot Lecture | beating MS: a story of B cells, with twists and turns. Mult Scler J. 2015;21(1):8–21. https://doi.org/10.1177/1352458514561911 Conceptual framework for B-cell-driven MS pathology; supports the mechanism-of-action description.
- Klein C, Lammens A, Schäfer W, et al. Epitope interactions of monoclonal antibodies targeting CD20 and their relationship to functional properties. MAbs. 2013;5(1):22–33. https://doi.org/10.4161/mabs.22771 Comparative epitope and effector function analysis explaining ADCC-predominant mechanism of ocrelizumab versus other anti-CD20 antibodies.
- Gibiansky E, Petry C, Mercier F, et al. Ocrelizumab in relapsing and primary progressive multiple sclerosis: pharmacokinetic and pharmacodynamic analyses of OPERA I, OPERA II and ORATORIO. Br J Clin Pharmacol. 2021;87(6):2511–2520. https://doi.org/10.1111/bcp.14658 Population PK/PD analysis underpinning the 26-day terminal half-life, 0.17 L/day clearance, 2.78 L central volume, and weight-covariate findings reported in the ADME table.
- Vukusic S, Carra-Dalliere C, Ciron J, et al. Pregnancy and multiple sclerosis: 2022 recommendations from the French multiple sclerosis society. Mult Scler J. 2023;29(1):11–36. https://doi.org/10.1177/13524585221129472 Practical guidance on managing DMTs including ocrelizumab around conception and lactation; informs the contraindications and counselling sections.
- Ciotti JR, Valtcheva MV, Cross AH. Effects of MS disease-modifying therapies on responses to vaccinations: a review. Mult Scler Relat Disord. 2020;45:102439. https://doi.org/10.1016/j.msard.2020.102439 Synthesis of vaccine response data across DMTs; supports the timing recommendations for inactivated and live vaccines on ocrelizumab.