On 9 April, during the Late-Breaking Science Session at the 2025 American Academy of Neurology (AAN) meeting, RemeGen announced results from a Phase III clinical trial evaluating the efficacy and safety of telitacicept. The results showed that telitacicept demonstrated a clinically meaningful efficacy and safety profile, displaying a significant improvement over 24 weeks with sustained reductions in total immunoglobulin G levels. This means that telitacicept has the potential to challenge currently marketed disease-modifying therapies (DMTs). Telitacicept reduces B-cell activity through a unique mechanism of action.
In generalised myasthenia gravis (gMG), B cells produce autoantibodies targeting the acetylcholine receptor (AChR) and muscle-specific tyrosine kinase (MuSK), thus disrupting neuromuscular transmission and leading to muscle weakness. Telitacicept, a novel fusion protein, inhibits B lymphocyte stimulator and a proliferation-inducing ligand, reducing B-cell activity.
The multicentre Phase III trial based in China enrolled 114 patients with gMG, confirmed as AChR+ or MuSK+, who were randomised to receive either subcutaneous telitacicept (240mg) or placebo for 24 weeks.
Telitacicept demonstrated significant improvements in Myasthenia Gravis Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scores after four weeks of treatment compared to placebo. At Week 24, telitacicept elicited a change in MG-ADL of -5.74, whereas the placebo group saw only a -0.91 change in MG-ADL score. Furthermore, 98.1% and 12.0% of Telitacicept and placebo group patients, respectively, had a three-point or higher reduction in MG-ADL. The key secondary endpoint was a change in QMG. At Week 24, change in QMG was -8.66 and -2.27 with the Telitacicept and placebo groups, respectively. Moreover, 87.0% and 16.0% of telitacicept and placebo group patients, respectively, had a five-point or higher reduction in QMG.
This data demonstrated that patients treated with telitacicept achieved clinically meaningful reductions in disease severity.
Telitacicept was also shown to be well-tolerated, with an overall adverse event (AE) incidence similar to that of the placebo group and an incidence of infection-related AEs that was lower than that of the placebo group (45.6% versus 59.6%). Displaying improvements in disease control, as measured by MG-ADL and QMG scores across a broad population that is seropositive for AChR or MuSK autoantibodies, is currently essential as most marketed therapies are indicated for AChR+ patients with gMG.
If Remegen wants to position telitacicept as a first-line DMT for MuSK+ MG patients, it would be competing against the well-established rituximab, which is also available as a cheap biosimilar.
The Phase III clinical trial results for telitacicept mark a significant milestone in the treatment of gMG. With clinically meaningful improvements in MG-ADL and QMG scores, telitacicept offers hope for both AChR+ and MuSK+ patients.
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