Immunovant's thyroid eye disease drug flunks pivotal trials

Immunovant shares were sliding today after it reported that its FcRn blocker batoclimab failed to show efficacy in a pair of phase 3 trials, wrecking plans to bring the drug to market for thyroid eye disease (TED).

The Roivant group company said that treatment with batoclimab had shown some improvement in the eye bulging (proptosis) associated with moderate to severe TED, a rare autoimmune disorder in which the muscles and fatty tissues behind the eye become inflamed, but did not achieve its primary efficacy objective in either the GO-1 or GO-2 studies.

Shares were down around 6% on the news, with a modest impact on the stock reflecting Immunovant's already-downgraded priority for the batoclimab programme. The drug didn't get a mention in the company's latest financial results announcement, as it is now focusing its resources on IMVT-1402, a follow-up FcRn blocker that it thinks has much greater potential.

In a statement, the Durham, North Carolina-based company said that batoclimab had shown efficacy in the initial high-dose stage of the trial, which lasted 12 weeks, but missed the mark in a subsequent 12-week, low-dose stage.

That pattern supports "the benefit of deeper IgG suppression," said Immunovant, adding that the data also back up the results of an earlier phase 2 trial of batoclimab in Graves' disease, a particular form of TED, which served as a proof-of-concept for FcRn blockade in this setting. There were also similar response rates for thyroid hormone normalisation to those seen in the mid-stage study.

Plans for batoclimab will now be discussed with Immunovant's development partner for batoclimab, South Korea's HanAll Biopharma, but any further investment in the programme from the US company looks unlikely.

In the meantime, topline data from Immunovant's phase 3 studies of IMVT-1402 in Graves' disease are expected next year, and the company has also completed enrolment in a potentially registrational trial in difficult-to-treat rheumatoid arthritis, with a readout possible before the end of the year.

It is also running studies of the drug in a range of other autoimmune conditions, including myasthenia gravis (MG), chronic inflammatory demyelinating polyneuropathy (CIDP), Sjögren's disease (SjD), and cutaneous lupus erythematosus (CLE).

Batoclimab also showed efficacy in MG, but Immunovant opted not to take that indication further in order to focus on IMVT-1402, which offers similarly potent reductions in IgG, without affecting levels of albumin and LDL cholesterol, which should deliver a better benefit-to-risk ratio.

Both drugs are given as subcutaneous injections, but IMVT-1042 can be delivered in lower volumes that could make it suitable for use with self-injection devices.

Amgen's IGF-1 blocker Tepezza (teprotumumab) became the first FDA-approved treatment for TED in 2020 and is given intravenously once every three weeks. It made revenues of more than $1.9 billion last year, up 3% on 2024.

Another drug in the IGF-1 class, Viridian Therapeutics' veligrotug, has a similar IV dosing schedule and has been filed with the FDA for TED, with a verdict due by 30th June.

Viridian is also developing another IGF-1 drug, elegrobart, which can be given subcutaneously by autoinjector every four or eight weeks, which is in late-stage clinical testing with a US filing expected early in 2027.

Photo by Charanjeet Dhiman on Unsplash