“plausibly explained much or all of the apparent treatment benefit,” Leerink analyst Porges wrote in July. In other words, if ApoE4 carriers are likely to decline faster, having less of them in the treatment arm might make the drug look more effective.
Eisai countered that skepticism today, showing ApoE4 carriers and noncarriers alike progressed at similar rates in the placebo group. They also detailed how BAN2401 cleared amyloid from patients’ brains—the impact was “very impressive,” said Morgan—and reduced levels of proteins that mark the presence of the disease. And not just that: Eisai doubled down to say that the study might even be underestimating BAN2401’s treatment effect in the 10mg group.
Investors weren’t necessarily impressed. Biogen shares were down nearly 1 percent to $299.47 in midday trading. Eisai, traded publicly in Japan, was down nearly 6 percent on the Tokyo exchange.
Eisai and Biogen issued a statement Thursday that they are talking to regulators about the next steps for BAN2401. They also plan to put patients who have been in the Phase 2 trial in an open-label extension study to follow their progress over time.
With today’s fresh information, a much larger Phase 3 study seems to be the only way to answer the outstanding questions. Jeffrey Cummings, director emeritus of the Cleveland Clinic’s brain health center and a consultant to Eisai, said as much during today’s presentation: “These results need to be confirmed by additional studies, but they are moving in the direction we wanted.”
As analysts pointed out today, however, both Biogen and Eisai have other Alzheimer’s drugs in their shared pipeline. It’s not clear if BAN2401 will merit hundreds of millions more dollars of investment.
Ben Fidler contributed to this report.
Image courtesy of Dierk Schaefer via a Creative Commons 2.0 license.
