- Ionis Pharmaceuticals and partner AstraZeneca on Tuesday announced that an RNA-based drug they’re co-developing succeeded in a Phase 3 study testing it in a form of the rare disease transthyretin amyloidosis that affects nerves.
- At an interim analysis performed after 35 weeks, the drug, called eplontersen, meaningfully reduced levels of a protein linked to disease progression compared to an external control group. Eplontersen also benefited patients on measures of neurological function and quality of life, the companies said. No specific safety concerns were reported.
- Ionis and AstraZeneca said they plan to seek regulatory approval this year based on the findings. But eplontersen’s prospects are uncertain, as it’s unclear how the drug compares to another marketed Ionis medicine or to two rival treatments from Alnylam Pharmaceuticals. Detailed study results will be presented at a future medical meeting.
The positive results are an important step for Ionis and AstraZeneca, which aim to turn eplontersen into a treatment for multiple forms of transthyretin amyloidosis and a commercial threat to Alnylam.
Eplontersen is a second-generation version of Tegsedi, Ionis’ first medicine for TTR amyloidosis. While Tegsedi was approved in the U.S. and Europe to treat the polyneuropathy, or nerve damage, that the disease causes, it hasn’t sold as well as Alnylam’s drug Onpattro. In clinical testing, the treatment was associated with certain side effects like low platelet counts that Onpattro wasn’t. It also wasn’t as effective as Alnylam’s drug.
Partially as a result, Ionis acquired and restructured a spin-out it created to sell Tegsedi and some of its other drugs. Tegsedi is now largely sold by the Swedish firm Sobi.
Ionis is counting on eplontersen to do better. The drug is meant to be more precise and to address a greater portion of people with the disease. It’s being tested for people with both inherited and acquired types of TTR amyloidosis, and is in late-stage testing for those with heart damage — a more common, deadlier form of the condition. (Tegsedi is only approved for polyneuropathy patients with inherited disease.)
The drug is important for other reasons, too. It’s the first Ionis medicine based on a newer technology known as LICA that the company believes can support less frequent administration of its drugs at lower doses. Eplontersen is administered once monthly, rather than weekly like Tegsedi, for example.
Behind eplontersen are other treatments using that same technology to treat a range of other conditions, from rare diseases like hereditary angioedema to more common ones like hepatitis B and hypertension.
The forthcoming study details could therefore determine eplontersen’s competitiveness as well as hint at how well future Ionis programs may work.
Investors will be paying close attention to whether eplontersen improved patients’ scores on a test of neurological function like Onpattro and Alnylam’s newly approved Amvuttro did, according to a note from Paul Matteis, an analyst at Stifel.
Side effect details will also be important to gauge whether the newer technology leads to a safer drug, he wrote in his June 21 note to clients.