In a closely watched readout, Biohaven’s autoimmune disease treatment led to a 37% reduction on average in levels of harmful antibodies at the highest reported dose. But the reduction was not as high as investors were hoping for, sending Biohaven’s shares $BHVN down 20% on Wednesday.
The results come from a study of healthy volunteers testing single doses of the experimental treatment at four different levels so far. Biohaven’s drug, BHV-1300, attempts to reduce levels of problematic self-attacking antibodies called IgG by transporting them to the liver to be destroyed. Other drugs that lower IgG — including from Immunovant, argenx and Johnson & Johnson — do so by blocking a protein called FcRn that’s needed for keeping up antibody levels in the blood.
In animal studies, BHV-1300 showed that it could reduce IgG levels by 75% after a single dose. In humans, investors were hoping for around a 50% to 60% reduction, according to Wall Street analysts.
But according to the data released Wednesday across four dose levels, a single dose of BHV-1300 resulted in an average reduction of IgG antibody levels from baseline of 5% to 37%.
While results were “underwhelming compared to the high bar set by many investors, with a differentiated mechanism of action we see potential for the product, especially in combination studies,” William Blair biotech analyst Tim Lugo said.
Biohaven said the results met their projections, and the company is planning to test the treatment at two higher doses than the ones reported, CEO Vlad Coric told Endpoints News Wednesday morning. Biohaven is now planning a study in rheumatoid arthritis where participants will get multiple doses.
“Our modeling says we’re going to hit that 70%. That’s still our expectation: 70% lowering by the time we’re done with the Phase 1,” Coric said, adding that the company expects to develop the treatment as an injectable.
Coric declined to disclose the dose levels in each cohort, but said the highest reported dose from Wednesday’s results was “the first dose that starts to get into a clinical range.”
Immunovant reported in September that in a healthy volunteer study, four weekly doses of its experimental injection led to a mean reduction of 63% in IgG antibodies. Analysts estimated that the single dose reduction was around 40% to 45%. The company announced in February it was planning to start four to five “potentially registrational” trials for its treatment by March 2025.
Others with IgG-lowering treatments include Johnson & Johnson and argenx. Argenx reported that Vyvgart, which was approved in 2021 for the autoimmune muscle disease myasthenia gravis, generated $1.2 billion in sales last year.
Shares of argenx $ARGX and Immunovant $IMVT rose 5% and 7%, respectively, Wednesday morning.
Biohaven is developing a second IgG degrader called BHV-1310 for myasthenia gravis. The company plans to submit an application to start clinical trials in 2024. When asked about the second degrader, Coric said it was “slightly more optimized.”
The company plans to develop one for more common disease, like rheumatoid arthritis, and the other for rare disease, he said. It also plays into the company’s commercial strategy, allowing it to go after two different pricing levels.
“It really is good to bifurcate the pricing in this space,” Coric said.