AstraZeneca spinoff scores maiden FDA approval, where it will field Alexion competition and an imminent Roche rival
About a year after the first-ever FDA approval for patients with neuromyelitis optica spectrum disorder (NMOSD), the agency has approved a second therapy for the rare autoimmune condition.
On Thursday, AstraZeneca spinoff Viela Bio scored its maiden approval for its lead drug, Uplizna, to treat NMOSD patients. It will compete with Alexion’s entrenched keystone therapy Soliris — a monoclonal antibody that targets complement protein C5 — which secured its NMOSD approval last June.
The disorder is often confused with multiple sclerosis as the immune system attacks its host, damaging healthy tissue in the spine and eyes. Although the majority of NMOSD patients are well-managed on Rituxan, there are still about a third of patients who relapse and are at risk for severe disabilities and even death, if left untreated. NMOSD can be associated with antibodies that bind to a protein called aquaporin-4 (AQP4) — binding of these antibodies appears to activate other components of the immune system, causing inflammation and damage to the central nervous system.
Uplizna, known chemically as inebilizumab, is an intravenous anti-CD19 drug. Its approval was based on a 230-patient study, in which 213 patients had antibodies against AQP4. The risk of relapse in the 161 anti-AQP4 antibody-positive patients who were treated with Uplizna was diminished by 77% versus placebo. In addition, 89% of patients in the AQP4 antibody-positive group remained relapse-free during the six-month period post-treatment compared to 58% of placebo subjects.
There was no evidence of a benefit in patients who were anti-AQP4 antibody negative.
The approval is largely in line with base case expectations — the drug has got no black box warning and the approval is for AQP4+ patients only, noted Stifel’s Derek Archila, anticipating the drug will generate about half a billion dollars in US sales at peak.
Viela’s shares $VIE jumped more than 6.5% to $54.82 in Friday premarket trading.
Soliris’ approval, which came with a black box warning, was based on a study that tested the drug in anti-AQP4 antibody-positive patients. Data showed 98% of Soliris-treated patients were relapse-free versus 63% on placebo. SVB Leerink’s Geoffrey Porges has forecast Soliris sales in NMOSD reaching about $700 million by 2024.
Within the NMOSD realm is another rival waiting in the wings: Roche and Chugai’s satralizumab. The drug inhibits IL-6 signaling, which is believed to play a key role in the inflammation that occurs in people with NMOSD.
Data from a late-stage study in the subgroup of patients that are AQP4-IgG seropositive — who tend to experience a more severe disease course — saw a 74% reduction in the risk of relapses in the satralizumab group. About 82.9% were relapse-free at 48 weeks and 76.5% relapse-free at 96 weeks when treated with satralizumab, compared to 55.4% and 41.1% with placebo, respectively. A marketing application for the therapy is currently under FDA review.
Viela executives have underscored that the fact Uplizna does not carry a black box warning should help it achieve first line status, and that the label reflects the drug’s ability to reduce hospitalization rates could prove to be a differentiator against other agents, notably satralizumab, Stifel’s Archila noted.
“While we agree with the latter, we do believe the extensive experience physicians have with rituximab in NMOSD and rituximab’s large safety database from its many years on the market will likely be a challenge for first-line usage of Uplizna,” Archila said.
While Viela has not disclosed Uplizna’s list price so far, they have generally laid out a range of $200,000-$280,000/year as feasible. That range is still far below Soliris, which at a staggering cost of more than $500,000 per year is one of the most expensive drugs in the world.
“Our estimate for the annual cost of treatment for NMOSD with biosimilar or branded rituximab is around $33,000-$37,000 and is considerably less than Viela’s proposed pricing for Uplizna, which could create another challenge for adoption,” Archila said.