Immunovant indicates positive topline results from Phase 2a IMVT-1401 trial

SAN DIEGO—Ligand Pharmaceuticals Inc.’s OmniAb partner, Immunovant, Inc., has announced positive topline results from ASCEND MG, a Phase 2a study of OmniAb-derived IMVT-1401 in patients with myasthenia gravis (MG). OmniAb is a three-species transgenic animal platform — using mice, rats and chickens — which consists of five different technologies used to produce mono- and bispecific human therapeutic antibodies.

“We are proud of the ongoing work by Immunovant and the strong results demonstrated by IMVT-1401 in patients who suffer with myasthenia gravis,” said John Higgins, chief executive officer of Ligand. “Importantly, IMVT-1401 holds potential to be a significant advancement in treatment for the approximately 65,000 myasthenia gravis patients in the U.S., should it be approved.”

ASCEND MG was a multicenter, randomized, placebo-controlled trial designed to evaluate the safety, tolerability, pharmacodynamics and efficacy of IMVT-1401 in patients with moderate-to-severe generalized myasthenia gravis. As evaluated in a pre-specified, pooled analysis of 15 patients who completed the six-week treatment period, patients treated with IMVT-1401 (n=10) showed a mean 3.8-point improvement on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale, versus a mean decline of +0.6 for placebo (n=5), a result that was statistically significant (p=0.029).

MG-ADL responder rates — defined in the study as the percentage of patients showing a > 2-point improvement — were 60 percent for patients treated with IMVT-1401, versus 20 percent for placebo. MG-ADL deep responder rates — the percentage of patients showing a > 6-point improvement — were 40 percent for patients treated with IMVT-1401, versus 0 percent for placebo.

Patients treated with IMVT-1401 also showed a highly statistically significant improvement on the Myasthenia Gravis Composite (MGC) scale, with an average improvement of 8.0 points versus a mean decline of +1.4 for placebo (p=0.006). And MGC deep responder rates — the percentage of patients showing a > 10-point improvement — were 40 percent for patients treated with IMVT-1401, versus 0 percent for placebo.

Consistent with previously reported Phase 1 results, IMVT-1401 was found to be generally safe and well-tolerated. There were no serious adverse events, no withdrawals due to adverse events and no imbalance in headaches. Mean reductions in total serum IgG from baseline for the 340 mg and 680 mg cohorts were 59 percent and 76 percent, respectively.

“Immunovant’s trial data follows positive Phase 3 results by CStone Pharmaceuticals earlier this month for their OmniAb program, where CStone announced a 50 percent reduction in the risk of disease progression or death for patients in their non-small cell lung cancer trial. OmniAb is a major antibody discovery platform and a key value-driver for Ligand. The positive clinical events are mounting for our proprietary platform, which is laying the potential for new drugs to be approved and generate royalties for Ligand,” noted Higgins. “We have a growing OmniAb partner base with an increasing number of late-stage programs with important upcoming clinical or regulatory events.”

Immunovant now plans to initiate a Phase 3 registration study with IMVT-1401 for the treatment of myasthenia gravis in the first half of 2021.