Strong top-line results from Immunovant Inc.’s phase IIa clinical trial of IMVT-1401 in treating moderate to severe generalized myasthenia gravis increased the competition with Momenta Pharmaceuticals Inc. and Argenx SE in the crowded anti-FcRn space.

Data from Immunovant’s multicenter, randomized, placebo-controlled trial of IMVT-1401, a fully human anti-FcRn monoclonal antibody, showed a 3.8-point mean improvement on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale that was statistically significant vs. placebo (p=0.029) and an 8.0-point mean improvement on the Myasthenia Gravis Composite (MGC) scale was highly statistically significant vs. placebo (p=0.006).

In the MG-ADL responder rates, the percentage of patients with a greater than 2-point improvement were 60% for IMVT-1401-treated patients vs. 20% for those taking placebo. MG-ADL deep responder rates, the percentage of patients showing a greater than 6-point improvement, were 40% for IMVT-1401-treated patients vs. 0% for placebo. MGC deep responder rates, the percentage of patients showing a greater than 10-point improvement, were 40% for IMVT-1401-treated patients vs. 0% for placebo.

Peter Salzmann, CEO, Immunovant

Subcutaneously delivered IMVT-1401 was found to be generally safe and well-tolerated with no serious adverse events, no withdrawals due to adverse events and no imbalance in headaches.

Results came from the study’s three arms, 340 mg IMVT-1401 weekly (N=5), 680 mg IMVT-1401 weekly (N=5), and placebo (n=5), of the six-week treatment period.

Based on the strong results, New York-based Immunovant said it plans to begin a registrational phase III study in the first half of 2021.

“I think we have two really nice levers that we can use creatively to design a tremendous protocol and finalize that in discussion with the FDA,” Peter Salzmann, Immunovant’s CEO, said on an Aug. 25 conference call with investors. “And those two levers are that we have the two doses and that both doses can be given as a subcutaneous injection. So that allows us flexibility across a range of disease severity and allows us to chronically dose patients easily. So we're going to maximize the use of those two levers to design a phase III protocol that, I think, is going to be really exciting for a wide range of patients with myasthenia.”

H.C. Wainwright analyst Douglas Tsao wrote Aug. 26 that the positive data, “coupled with a best-in-class” subcutaneous administration, are key differentiators for IMVT-1401 in the anti-FcRn development. The data provides, he continued, an important proof-of-concept for IMVT-1401 in myasthenia gravis that “stacks-up well compared to competitor’s I.V. administered mAbs.”

Tsao added that statistical significance was achieved despite the study not being powered accordingly, as only 15 patients were enrolled. “The robustness of the data across both doses, in our view, creates the opportunity for Immunovant to deploy flexible, patient-friendly dosing regimens,” he wrote.

That success, Tsao added, along with a planned announcement by Immunovant for three additional indications for IMVT-1401 in the next 12 months, “and the recent interest in the anti-FcRn mAb space” makes the company a “potential acquisition target.”

Immunovant stock (NASDAQ:IMVT) has steadily risen nearly 60% since late July, when shares went for about $22 each. On Aug. 26, they closed at $34.55 each, down less than one-half a percentage point on the day.

The competition

On Aug. 19, Johnson & Johnson said it would pay $6.5 billion in an all-cash acquisition of Momenta, strengthening the Janssen Pharmaceutical Companies of Johnson & Johnson’s immune-mediated disease portfolio and growing its interest in autoantibody-driven disease therapies. A massive part of the deal is full global rights to Momenta’s nipocalimab, an G1 anti-FcRn monoclonal antibody. Top-line phase II data from an interim analysis of nipocalimab (M-281) in treating generalized myasthenia gravis released in mid-June showed efficacy in the MG-ADL score, which was the primary endpoint.

Argenx, of Breda, the Netherlands, in early July set a new highwater mark for a follow-on offering by a publicly listed European firm, raising $863 million, including the overallotment option, on the back of positive data from a pivotal phase III trial of the anti-neonatal-Fc-receptor antibody fragment efgartigimod in generalized myasthenia gravis. The company said it is on track to submit a BLA for efgartigimod by the end of 2020.

The BLA will be based on data included from a global phase III experiment in 167 adults that met its primary endpoint defined as percentage of responders on the MG-ADL score among acetylcholine receptor-antibody positive generalized MG patients. Responders are defined as having at least a two-point improvement on the MG-ADL score for at least four consecutive weeks.

Others developing anti-FcRn agents include UCB Pharma SA’s rozanolixizumab and Alexion Pharmaceuticals Inc.’s ALXN-1830.

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