Roche says Lunsumio combo hits PFS goal in Phase 3 CELESTIMO trial

What Roche reported

On 17 September 2026, Roche said its Phase III CELESTIMO study met its primary endpoint: Lunsumio (mosunetuzumab) plus lenalidomide significantly improved progression-free survival versus rituximab plus lenalidomide in adults with relapsed or refractory follicular lymphoma ^[1]. The result was carried the same day by Endpoints News and by wire syndication of the company statement ^[2][3].

Why it matters

Lunsumio is a CD20xCD3 bispecific T-cell engager. Its US clearance in follicular lymphoma is an accelerated approval granted on response rate for patients after two or more prior lines, and that clearance is contingent on a confirmatory trial verifying clinical benefit ^[4]. CELESTIMO is that confirmation. A win on the PFS primary endpoint gives Roche the evidence to convert the accelerated approval to full approval, and Endpoints News reads the result as clearing the path to a broader label for the bispecific ^[2].

The trial also moves Lunsumio out of monotherapy salvage and into a chemo-free doublet with lenalidomide, tested head-to-head against rituximab plus lenalidomide — the backbone that anchors earlier-line relapsed follicular lymphoma ^[1]. A regimen that beats it on PFS competes directly for that treatment slot.

Who is exposed

The comparator arm is the exposed position: rituximab plus lenalidomide (Roche's own MabThera/Rituxan in the trial) is the control that Lunsumio's combination outperformed on PFS ^[1]. Prognyx has no dossier data on cross-trial positioning against other bispecifics and does not assert one.

What to watch

• The PFS magnitude. Roche's 17 September 2026 release reports a significant PFS improvement in CELESTIMO; the hazard ratio and median PFS will decide how strong the confirmatory case reads ^[1].
• A regulatory filing. Endpoints frames CELESTIMO as clearing the path, not as a submission ^[2].
• The adjacent program. FDA accepted a supplemental Biologics License Application on 18 June 2026 for Lunsumio plus Polivy in relapsed/refractory large B-cell lymphoma ^[6], and a Phase III trial of mosunetuzumab plus polatuzumab vedotin versus R-GemOx is active but no longer recruiting, with results flagged as posted ^[10]. Genentech's Lunsumio application sits in Drugs@FDA under BLA761263 ^[5].

What Prognyx could not verify

Prognyx could not verify CELESTIMO's ClinicalTrials.gov identifier or current registry status. Prognyx could not confirm the CELESTIMO hazard ratio, median PFS, significance threshold, SEC filing, FDA action or full-approval submission from public sources as of this briefing. The event rests on Roche's release and trade reporting ^[1][2][3].

The now-what

• If you run a competing follicular lymphoma program built on the rituximab-lenalidomide backbone, treat a chemo-free bispecific doublet with a PFS win as a live threat to that positioning and pressure-test your differentiation before the magnitude data lands.
• If you are a BD team scouting CD3 bispecific combinations, note that Roche is widening Lunsumio from third-line monotherapy toward earlier-line doublets and cross-B-NHL combinations ^[1][6].
• Hold firm commitments until the hazard ratio and any filing timeline are public.

Verdict: elevated threat to rituximab-lenalidomide positioning in relapsed follicular lymphoma; the window to act is before the PFS magnitude and any full-approval filing reach the public.