IMVT-1402
Medium EvidenceIMVT-1402 (international nonproprietary name imeroprubart; originally HL161ANS) is Immunovant/Roivant's investigational, next-generation, fully human IgG1 monoclonal antibody that blocks the neonatal Fc receptor (FcRn). It is a re-engineered successor to batoclimab, built to keep batoclimab's deep IgG-lowering while removing that molecule's defining liability: because FcRn recycles serum albumin as well as IgG, first-generation FcRn blockers reproducibly lowered albumin and raised LDL cholesterol, and IMVT-1402 was specifically designed to spare albumin and lipids. Like the approved FcRn blockers efgartigimod, nipocalimab and rozanolixizumab it lowers circulating IgG - including pathogenic autoantibodies - but it is distinguished by two things: a low-volume subcutaneous autoinjector for at-home self-administration, and Phase 1 data showing 60-80% IgG reduction with no albumin drop and no LDL rise. It is now Immunovant's lead pipeline asset, advancing across roughly six autoimmune indications with potentially registrational Graves' disease and myasthenia gravis readouts expected in 2027.
What It Is
IMVT-1402 is the FcRn class's answer to its own biggest problem. The neonatal Fc receptor (FcRn) rescues immunoglobulin G from lysosomal degradation and recycles it into the blood, giving antibodies their long half-life; blocking FcRn routes unrescued IgG - including the pathogenic autoantibodies that drive diseases like myasthenia gravis, Graves' disease and rheumatoid arthritis - to destruction, lowering total IgG by roughly 60-80%. Every FcRn blocker does this. But FcRn also recycles serum albumin, so the first-generation antibodies - most clearly batoclimab - produced a mechanistic 'tax': deep, sustained blockade lowered serum albumin and raised LDL and total cholesterol. Immunovant deliberately shelved batoclimab (even after it hit its Phase 3 myasthenia endpoint) and advanced IMVT-1402, a fully human IgG1 antibody engineered to occupy FcRn and lower IgG just as potently while leaving albumin recycling and lipids largely intact. Phase 1 healthy-volunteer studies delivered exactly that profile: four weekly 300 mg subcutaneous doses cut total IgG by about 63% with no decrease in serum albumin below baseline and no increase in LDL-C above baseline, while a 600 mg regimen reached roughly 74% IgG reduction (about 80% at steady state after 6-8 weeks) with the same clean albumin/lipid picture. Delivered as a small, fixed-dose subcutaneous injection designed for an at-home autoinjector, IMVT-1402 is now Immunovant/Roivant's strategic priority, with potentially registrational trials running in Graves' disease, difficult-to-treat rheumatoid arthritis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy (CIDP) and Sjogren's disease, plus a proof-of-concept study in cutaneous lupus - a breadth that reflects both the confidence built by batoclimab's clinical proof-of-concept and the platform logic of a better-tolerated 'best-in-class' FcRn antibody. It carries the international nonproprietary name imeroprubart and originated from HanAll Biopharma's HL161ANS program.
Regulatory Status
Why Researchers Study It
IMVT-1402 matters to researchers as the deliberate, engineered fix for the FcRn class's signature liability, and as a live test of whether 'best-in-class' can be designed rather than discovered. The neonatal Fc receptor recycles both IgG and serum albumin, so first-generation FcRn blockers such as batoclimab lowered IgG effectively but also dropped serum albumin and raised LDL/total cholesterol - an on-target consequence, not a random side effect. IMVT-1402 was purpose-built to decouple those effects: to lower IgG as deeply as batoclimab (60-80%) while sparing albumin and lipids, and its Phase 1 data delivered exactly that dissociation, making it a clean pharmacological demonstration that albumin recycling and IgG recycling can be separated at the receptor. That is why Immunovant used batoclimab as clinical proof-of-concept and then handed the market to its own improved successor. Beyond the mechanism, IMVT-1402 is studied because its at-home subcutaneous autoinjector and broad, potentially registrational program - Graves' disease, myasthenia gravis, CIDP, difficult-to-treat rheumatoid arthritis, Sjogren's disease and cutaneous lupus - probe how far a single, better-tolerated FcRn antibody can extend across IgG-mediated autoimmunity, including diseases (like difficult-to-treat RA with elevated ACPA autoantibodies) where deeper, cleaner IgG lowering might succeed where earlier agents were limited by tolerability.
Proposed Mechanisms
- Fully human, full-length IgG1 monoclonal antibody that binds the neonatal Fc receptor (FcRn) at the IgG-binding site with high affinity - a complete antibody like batoclimab rather than efgartigimod's engineered Fc fragment, originated from HanAll Biopharma's HL161ANS program and produced as a recombinant biologic
- Competitively blocks FcRn-mediated recycling of IgG: FcRn normally captures IgG inside cells and returns it to the circulation before lysosomal degradation, so occupying the receptor routes circulating IgG - including pathogenic autoantibodies - to destruction, lowering total IgG by roughly 60-80% (about 63% after four weekly 300 mg doses and about 74%, up to ~80% at steady state, at 600 mg weekly)
- Engineered to spare albumin recycling: because FcRn also rescues serum albumin, first-generation FcRn blockers lowered albumin and raised LDL/total cholesterol, whereas IMVT-1402 is designed so that at IgG-lowering doses it produces no decrease in serum albumin below baseline and no increase in LDL-C above baseline - the defining differentiator from batoclimab
- Selective for IgG: spares IgM, IgA and complement, depleting the antibody isotype that mediates most autoimmune disease without the broad immunosuppression of steroids or the mechanical burden of plasma exchange or high-dose IVIg
- Reversible and titratable - IgG recovers after dosing stops - enabling induction ('reduce') and maintenance or step-down ('recover') schedules and allowing dose to be matched to depth of IgG lowering
- Delivered as a low-volume, fixed-dose subcutaneous injection designed for at-home self-administration via an autoinjector, positioning it as a convenient, better-tolerated member of the FcRn class
Evidence Snapshot
| Study Type | Model | Outcome | Link |
|---|---|---|---|
| Phase 1 multiple-ascending-dose (healthy volunteers) - 300 mg cohort | Healthy adults given four once-weekly 300 mg subcutaneous doses of IMVT-1402 | Mean total IgG reduction of about 63% from baseline, with no decrease in serum albumin below baseline and no increase in LDL-C above baseline - demonstrating deep IgG lowering with an albumin- and lipid-sparing profile | Source |
| Phase 1 multiple-ascending-dose (healthy volunteers) - 600 mg cohort | Healthy adults given four once-weekly 600 mg subcutaneous doses of IMVT-1402 | Mean total IgG reduction of about 74% (approximately 80% at steady state after 6-8 weeks) with the same albumin- and lipid-sparing profile, confirming best-in-class potential relative to batoclimab | Source |
| Phase 2 (difficult-to-treat rheumatoid arthritis) - preliminary Week 16 data | Adults with heavily pretreated (difficult-to-treat) rheumatoid arthritis, many with elevated ACPA autoantibodies, treated with subcutaneous IMVT-1402 | Week 16 ACR20/ACR50/ACR70 response rates of approximately 72.7%/54.5%/35.8%; randomized, placebo-controlled Period 2 data expected in the second half of 2026 to confirm durability | Source |
| Phase 3 (generalized myasthenia gravis) - ongoing, registrational | Adults with mild to severe generalized myasthenia gravis; multicenter, randomized, double-blind, placebo-controlled study of once-weekly subcutaneous IMVT-1402 over ~26 weeks (e.g., NCT07039916) | Enrolling; designed to assess efficacy, safety and tolerability. Topline data expected in calendar year 2027 | Source |
| Phase 3 / potentially registrational (Graves' disease) - ongoing | Adults with Graves' disease (hyperthyroidism) treated with once-weekly subcutaneous IMVT-1402 to lower pathogenic TSHR autoantibodies (e.g., NCT07286006) | Enrolling; Graves' disease is a flagship indication for IMVT-1402 given batoclimab's earlier drug-free remission signal. Topline data expected in calendar year 2027 | Source |
Commonly Discussed Benefits
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Safety & Cautions
- IMVT-1402 (imeroprubart) is an investigational, unapproved biologic administered only under clinical-trial supervision; it is not a supplement or a self-sourced research chemical, and any product sold as 'IMVT-1402', 'imeroprubart' or 'HL161ANS' outside a clinical trial is unverified and should not be used.
- Like all FcRn antagonists, it lowers protective IgG (roughly 60-80%), so the principal risk is infection; trial safety monitoring emphasizes respiratory, urinary and other infections during periods of low IgG.
- Its central claim - deep IgG lowering without the albumin drop and LDL rise seen with batoclimab - rests primarily on Phase 1 healthy-volunteer data and early Phase 2 results; confirmation of both efficacy and the albumin/lipid-sparing profile across large, controlled Phase 3 trials is still pending (topline Graves' and myasthenia data expected in 2027).
- As an investigational injectable antibody it can cause injection-site and hypersensitivity reactions; it must never be combined with other immunosuppressants or used in pregnancy outside a trial without specialist oversight, given the unknown risks of maternal IgG lowering.
- FcRn blockade does not help every antibody-associated disease - batoclimab hit its myasthenia endpoint but failed on proptosis in thyroid eye disease, and rozanolixizumab failed in CIDP - so IMVT-1402's breadth across six indications is a hypothesis being tested, not an established result.
- It is a prescription-only investigational medicine; there is no legitimate over-the-counter or research-chemical source, and clinical benefit and long-term safety have not been established outside ongoing trials.
Comparisons
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Citations
- [1] Immunovant Announces IMVT-1402, a Next Generation Anti-FcRn - Immunovant PubMed
- [2] Roivant Announces Positive IMVT-1402 Initial 600 mg MAD Results that Confirm Best-in-Class Potential - Roivant Sciences PubMed
- [3] Immunovant (NASDAQ: IMVT) shifts to IMVT-1402 with broad late-stage autoimmune program - 10-K filing summary PubMed
- [4] IMVT-1402 Shows Strong Results in Rheumatoid Arthritis - AllSci PubMed
- [5] Phase 3, Randomized, Placebo-Controlled Study of IMVT-1402 in Generalized Myasthenia Gravis (NCT07039916) - UCSF Clinical Trials PubMed
- [6] IMVT-1402 in Adult Participants With Graves' Disease (NCT07286006) - UCSF Clinical Trials PubMed
- [7] From promise to practice: evaluating the clinical impact of FcRn inhibition in IgG-mediated autoimmune rheumatic diseases - PMC PubMed
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Nipocalimab
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Rozanolixizumab
High EvidenceRozanolixizumab (brand name Rystiggo, development code UCB7665) is a humanized IgG4 monoclonal antibody that blocks the neonatal Fc receptor (FcRn), developed by UCB. Like efgartigimod and nipocalimab it lowers circulating immunoglobulin G (IgG) - including the pathogenic autoantibodies that drive many autoimmune diseases - by binding FcRn and preventing it from recycling IgG back into the blood, so unrescued IgG is routed to the lysosome and degraded, typically cutting total IgG by roughly 70-80% while sparing IgM, IgA, complement, and albumin. Unlike efgartigimod's engineered Fc fragment, rozanolixizumab is a full-length humanized antibody, and unlike nipocalimab's intravenous infusion it is given as a rapid subcutaneous infusion (including via an on-body delivery device), typically in weekly cycles that are repeated based on clinical response rather than continuously. The FDA approved Rystiggo on June 27, 2023 for generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine-receptor (AChR) antibody-positive or anti-muscle-specific-tyrosine-kinase (MuSK) antibody-positive - making it the first therapy ever approved to treat both of those gMG subtypes - on the strength of the Phase 3 MycarinG trial. It has since been studied across other IgG-mediated diseases, including chronic inflammatory demyelinating polyneuropathy (CIDP), where it did not show meaningful benefit and was not advanced to Phase 3, and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), primary immune thrombocytopenia (ITP), and other autoantibody conditions where development continues. The European Medicines Agency approved rozanolixizumab in January 2024 and the UK MHRA in March 2024.
Batoclimab
High EvidenceBatoclimab (development codes IMVT-1401, RVT-1401, HBM9161, HL161) is an investigational, fully human IgG1 monoclonal antibody that blocks the neonatal Fc receptor (FcRn), developed by Immunovant/Roivant (U.S. and Canada) and Harbour BioMed (Greater China) under license from HanAll Biopharma. It is not a small synthetic peptide but a full-length antibody given as a low-volume subcutaneous injection that patients can self-administer at home. Like the approved FcRn blockers efgartigimod, nipocalimab and rozanolixizumab, it lowers circulating IgG - including pathogenic autoantibodies - but it is best known for two things the others are not: it is the FcRn blocker that generated positive Phase 3 myasthenia gravis data yet was deliberately NOT filed for U.S. approval, and it is the one whose FcRn-mediated albumin recycling blockade produces a distinctive on-target signal of lowered serum albumin and raised LDL cholesterol - the exact liability that drove its makers to a re-engineered successor, IMVT-1402.