Immunovant’s next-generation anti-FcRn therapeutic IMVT-1402 posted a clean safety profile in a Phase 1 study, but a surprise disclosure in Tuesday’s topline reveal also served to differentiate it relative to the Roivant subsidiary’s first-gen asset.

This news added to anticipation for a forthcoming readout.

IMVT-1402 emerged unsullied from the study, which evaluated the biologic for changes in cholesterol/albumin and other measures of safety and tolerability. Immunovant disclosed single-ascending dose (SAD) and — unexpectedly — preliminary multiple-ascending dose (MAD) data, as well.

The SAD results suggest that subcutaneous dosage of the drug is able to achieve significant IgG reductions with a clean safety and tolerability profile, similar to that which has been observed with Roivant’s first-generation asset batoclimab (IMVT-1401). This is a monoclonal antibody targeting the neonatal Fc-Receptor (FcRn) for treating IgG-mediated autoimmune diseases. 

“These first-in-human results are consistent with those observed in prior non-human primate studies, and we look forward to sharing additional MAD data in November,” Immunovant CEO Pete Salzmann said in the Tuesday release. 

The addition of the MAD data, released ahead of schedule, kicked expectations up a notch. Those data showed no decrease in serum albumin below baseline or increase in low-density lipoprotein cholesterol (LDL-C) above baseline after 4 weeks of dosing in the 300mg cohort, both of which were concerns observed with batoclimab.

“We were originally expecting only SAD data this month, with MAD data anticipated by Oct/Nov – and in our view, the SAD data alone would’ve provided little insight to the relative efficacy/safety of the asset vs. the company’s first-generation asset (batoclimab),” explained Raymond James analyst Danielle Brill in an investor note. “However, with the initial MAD data presented for the low 300mg dose, it looks like ‘1402 is in fact differentiated from batoclimab.”

The data suggest IMVT-1402 is positioned well as a potential treatment for a variety of autoimmune diseases. Analysts, meanwhile, focused on how the drug stacks up against competing anti-FcRns. 

The mean IgG reduction observed with 4-weekly subcutaneous doses of IMVT-1402 was about 63%, while Argenx’s FcRn efgartigimod showed a 75% reduction in its Phase 1 trial. 

While IMVT-1402’s MAD data were “slightly inferior” to those of efgartigimod, ‘1402’s overall profile “looks competitive,” observed Leerink analyst Thomas Smith in a Tuesday note.

“We believe the higher 600mg dose of ‘1402 could perform in line or better than efgar, but note this would then require two separate SC injections,” Smith wrote. “Bottom-line, it looks like IMVT has a competitive anti-FcRn drug, though it is premature to call its efficacy best-in-class.”

Based on the data, the Leerink team boosted their revenue forecast for ‘1402 across multiple indications, modeling roughly $2.7 billion in batoclimab/’1402 franchise revenues by 2035.

“We view potential indication expansion for batoclimab and IMVT-1402 into other IgG-driven diseases as an opportunity to create additional value beyond the indications expressly contemplated in our model,” added Smith.

Immunovant is pursuing several indications for batoclimab, including myasthenia gravis, thyroid eye disease, chronic inflammatory demyelinating polyneuropathy and Graves’ disease.

Additional healthy volunteer data from ‘1402’s 600mg MAD cohort are expected in November. Indeed, multiple analysts say that data could be the driver that ultimately unlocks full credit for batoclimab and Immunovant’s FcRn franchise.

It remains to be seen whether longer dosing durations and the higher 600mg dose will have a more significant impact on albumin/LDL. Regardless, analysts say ‘1402 already appears to have a cleaner safety profile than batoclimab.

While she agreed it’s premature to call ‘1402 best-in-class, concluded Brill, “there is room for more than one anti-FcRn in the market, and we believe multiple agents can achieve blockbuster status.”