In two nearly identical phase III trials, NEPTUNUS-1 and NEPTUNUS-2, the B-cell–targeting biologic ianalumab met its primary endpoint: patients receiving monthly injections had a larger drop in ESSDAI disease activity scores than placebo. But the margins were thin—just 1.3 and 1.0 points on a scale where baseline scores averaged around 12—and the first trial's difference was only borderline significant (P=0.0496). Pooling the data made the result look stronger statistically, though the absolute effect remained small.
Secondary outcomes were mostly negative. There were no significant improvements in salivation or dryness, and the proportion of patients achieving a clinically meaningful 5-point responder threshold was numerically higher with ianalumab but not statistically different. The every-three-months dosing arm showed no benefit. Investigators downplayed the results, and in an accompanying editorial, Simone Negrini of the University of Turin wrote that the consistency between two trials should not be dismissed, but he still called the drug's usefulness uncertain. Both investigators and the editorial agreed adverse effects were not concerning.
Despite the mixed data, Novartis has started a new placebo-controlled phase III trial called THALASSA in patients with high symptom burden, with a planned 570 participants and an estimated completion date in 2029. The company had earlier promised regulatory submissions in early 2026, then pushed the timeline to the third quarter—which has now passed without public confirmation of a filing.