Roche's satralizumab cuts relapse risk in rare disease phase 3

Roche is preparing to talk to regulators about bringing satralizumab to market. (Roche)

Roche has presented phase 3 data on its neuromyelitis optica spectrum disorder (NMOSD) treatment satralizumab. The trial linked the anti-IL-6 antibody to a 55% reduction in the risk of relapse, showing the drug works but leaving scope to question how it will fare against rival drugs.  

NMOSD, a previously underserved rare disease that causes blindness and paralysis, is emerging as a competitive area. Alexion Pharmaceuticals won approval for Soliris in the indication in June. Viela Bio, a spinout from AstraZeneca, is gearing up to bring its own NMOSD drug candidate, inebilizumab, to market using the proceeds of a planned $150 million IPO. And Roche is set to talk to regulators about satralizumab.

Roche shared more data on satralizumab this week. Investigators randomized 95 patients who had suffered at least one relapse in the previous year to receive once-monthly subcutaneous injections of satralizumab or placebo and recorded how long they went without a relapse.

Satralizumab cut the risk of relapse by 55% over placebo. At 74%, the risk reduction figure was higher still in patients with aquaporin-4 antibodies, which are found in around 80% of people with NMOSD. 

“We are encouraged by these results and look forward to working with regulators over the coming months to bring satralizumab to people living with NMOSD as soon as possible,” Roche Chief Medical Officer Sandra Horning said in a statement. 

The publication of the data follows the release of results on the use of satralizumab as an add-on therapy. Used in that context, satralizumab cut the risk of relapse by 62% in a study population featuring people with and without aquaporin-4 antibodies. In patients with the antibodies, the figure rose to 79%.

Alexion and Viela posted higher numbers in their clinical programs, although differences between the studies and the general unreliability of cross-trial comparisons make it hard to draw firm conclusions. Alexion’s Soliris cut the risk of relapse by 94% when given as an add-on to patients with aquaporin-4 antibodies. Viela’s inebilizumab achieved a 73% risk reduction when administered as a monotherapy to people with and without the antibodies. 

Factors other than those figures may influence uptake of the three drugs. All the therapies work via different mechanisms and have different dosing regimens. The six-month dosing schedule of Viela’s inebilizumab may make it the most convenient.