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TACI-Fc Fusion Protein (Dual APRIL and BLyS Inhibitor) Pregnancy: Avoid — insufficient data; B-cell suppression with unknown fetal consequences.

Telitacicept (APRIL/BLyS Dual Inhibitor — SLE/IgA Nephropathy)

Brand names: Tai Ai (泰爱) — China; RC18 — global trials

Adult dose

Dose: 160 mg SC once weekly (Phase 3 SLE dose); IgA nephropathy trial dose: 80 or 240 mg SC weekly
Route: Subcutaneous
Frequency: Once weekly
Max: 160 mg/week (SLE trial); dose varies by indication
TACI-Fc fusion protein — TACI (transmembrane activator and CAML-interactor) naturally binds both BAFF/BLyS and APRIL. Telitacicept captures both survival factors simultaneously — superior to belimumab (only anti-BLyS) or ianalumab (anti-BAFF receptor). Approved in China for SLE (2021). Phase 3 global trials ongoing (TELLUS-SC, TELESCOPE). Not yet MHRA/FDA approved.

Paediatric dose

Route:
Not licensed in paediatrics.

Dose adjustments

Renal

No dose adjustment expected — Fc fusion protein clearance.

Hepatic

No dose adjustment expected.

Clinical pearls

  • Phase 2 trial (Wang et al. Arthritis Rheumatol 2021): telitacicept 160 mg weekly vs placebo in SLE — SRI-4 response at 52 weeks: 83% vs 57% in the active SLE subgroup (p=0.003); CLASI skin score significantly improved; anti-dsDNA fell 66%. Results attracted global attention as potentially the most effective anti-B-cell approach in SLE to date
  • Dual APRIL+BAFF inhibition advantage: BLyS/BAFF primarily drives mature B-cell survival (naive → plasma cell); APRIL primarily drives plasma cell longevity (survival of terminally differentiated antibody-secreting cells). Single BAFF inhibition (belimumab) leaves APRIL-dependent long-lived plasma cells intact — these sustain autoantibody production. Dual blockade (telitacicept) addresses both early and late B-cell compartments
  • IgA nephropathy emerging indication: APRIL is the key survival factor for IgA-producing plasma cells in Peyer's patches. Phase 3 TELESCOPE trial in IgA nephropathy (telitacicept) showed dramatic proteinuria reduction — potentially transformative for a condition where targeted biologic therapy has been lacking (iptacopan and sparsentan are the other emerging IgAN treatments)

Contraindications

  • Active serious infection
  • Active hepatitis B
  • Live vaccines

Side effects

  • Injection site reactions
  • Infections (upper respiratory tract)
  • Hypogammaglobulinaemia (B-cell and plasma cell depletion)
  • Nasopharyngitis
  • Fatigue

Interactions

  • Other B-cell depleting agents (additive immunosuppression)
  • Live vaccines (absolute contraindication)

Monitoring

  • Anti-dsDNA and complement C3/C4 (SLE disease biomarkers — monthly for first 6 months)
  • SLEDAI score (disease activity — at each visit)
  • Serum IgG levels (B-cell and plasma cell depletion monitoring)
  • Proteinuria/urinalysis (SLE nephritis or IgAN monitoring)
  • HBV serology before initiation
  • Infection surveillance

Reference: BNFc; Wang et al. Arthritis Rheumatol 2021 (Phase 2 SLE trial); Phase 3 TELLUS-SC and TELESCOPE trials (ongoing); China NMPA Approval 2021; Tak et al. Ann Rheum Dis 2023 (IgAN review). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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