An absolute response rate without a comparator is a number, not a result. MoonLake has disclosed that 42.1% of biologic-naïve patients on sonelokimab 60 mg with induction reached ACR50 at Week 16, and has explicitly withheld the placebo arm, the treatment arm detail and every comparative analysis until the Phase 3 programme finishes. The company says the trial met its endpoints, so somebody has seen the comparison. Nobody outside has, and nobody will for some time.

• The blinding is deliberate and defensible, and that is the part worth explaining rather than complaining about. IZAR-2 is still enrolling and completes in the third quarter. It runs in a TNF-refractory population and is the first psoriatic arthritis trial to carry a risankizumab active reference arm. Publishing a placebo delta from IZAR-1 now would flow into investigator behaviour and patient expectation inside a trial being conducted against an active comparator. The unblinding protocol was agreed with the FDA precisely to prevent that. MoonLake is trading market clarity for trial integrity, which is the right trade, and it still leaves everyone pricing a result they cannot inspect.
• Do not compare 42.1% against the Phase 2 figure, and expect a great many people to do exactly that. ARGO reported roughly 60% ACR50 at Week 24. IZAR-1 reports 42.1% at Week 16. Those are different timepoints in a disease where ACR50 typically keeps climbing between four and six months, so the numbers are not comparable and any reading of a step down is an artefact of the calendar rather than the drug. Week 52 is the figure to demand, because it arrives with durability and radiographic progression and it is measured where the Phase 2 comparison finally becomes fair.
• Competitive frame: the answer that matters is not in this trial. IZAR-2 puts sonelokimab against risankizumab in patients who have already failed TNF inhibition, which is the population where prescribers genuinely choose between mechanisms and where an IL-17A and IL-17F Nanobody has to beat an IL-23 inhibitor rather than a placebo. A 42.1% ACR50 in biologic-naïve patients establishes that the drug works. IZAR-2 will establish whether it displaces anything. Everything commercially decisive about sonelokimab in this indication sits inside a trial that has not finished enrolling.