FDA Accepts Roche's Application for Lunsumio and Polivy Combination in Relapsed or Refractory Large B-Cell Lymphoma

Roche announced on June 18, 2026 that the FDA has accepted for review its supplemental Biologics License Application (sBLA) for Lunsumio VELO (mosunetuzumab), a subcutaneous CD20xCD3 bispecific T-cell engager, in combination with Polivy (polatuzumab vedotin), a CD79b-targeted antibody-drug conjugate (ADC), for the treatment of adults with relapsed or refractory large B-cell lymphoma (LBCL) who have received at least one prior line of systemic therapy. The FDA has set a target decision date of February 9, 2027.¹

What disease does this combination target?

Large B-cell lymphoma, composed predominantly of diffuse large B-cell lymphoma (DLBCL), is the most common subtype of non-Hodgkin lymphoma, with more than 18,000 new diagnoses annually in the US.¹ While the disease is generally responsive to frontline immunochemotherapy, approximately 40% of patients will experience relapse or develop refractory disease.² At that stage, treatment options are limited and prognosis is poor.²

Access to advanced salvage therapies — including CAR-T cell therapy — remains uneven. Structural and geographical barriers mean that patients in rural areas or outside specialized academic transplant centers may face significant delays or be unable to receive these treatments at all.¹ The Lunsumio and Polivy combination was designed with an outpatient-friendly administration profile, potentially allowing treatment to take place in community settings where most US patients receive care.¹

What did the SUNMO trial show?

The sBLA acceptance is supported by data from the Phase 3 SUNMO trial (NCT05171647), a randomized, open-label, multicenter study evaluating mosunetuzumab plus polatuzumab vedotin versus rituximab, gemcitabine, and oxaliplatin (R-GemOx) in transplant-ineligible patients with relapsed or refractory LBCL. The trial enrolled 208 patients, randomized 2:1 to the experimental or comparator arm, with dual primary endpoints of progression-free survival (PFS) and overall response rate (ORR).³

At a primary analysis with a median follow-up of 23.2 months, the combination demonstrated a statistically significant 59% reduction in the risk of disease progression or death compared to R-GemOx (HR 0.41, 95% CI: 0.28–0.61; p<0.0001), with a median PFS of 11.5 months versus 3.8 months for the comparator arm.¹ Updated data presented at both ASCO 2026 and the European Hematology Association Congress extended the median follow-up to 28.3 months and continued to show consistent PFS benefit, with no new safety signals identified.¹

In the second-line subgroup specifically, updated ASCO data showed the combination reduced the risk of progression or death by 62%, with an overall response rate of 75% and a complete response rate of 61%.⁴

Cytokine release syndrome (CRS), a known risk with bispecific T-cell engagers, occurred in approximately one in four patients in the Lunsumio VELO plus Polivy arm, with fewer than 5% of events reaching Grade 2 or 3 severity.¹ The safety profile was consistent with what has been reported for each agent individually.¹

How does this combination work mechanistically?

Mosunetuzumab and polatuzumab vedotin engage LBCL tumor cells through distinct and complementary pathways. Mosunetuzumab is a CD20xCD3 bispecific antibody that simultaneously binds CD20 on malignant B cells and CD3 on circulating T cells, redirecting endogenous T-cell cytotoxicity toward the tumor independently of T-cell priming.¹ Polatuzumab vedotin binds CD79b — a protein preferentially expressed on mature B cells — and delivers the cytotoxic agent monomethyl auristatin E directly into the target cell, inducing apoptosis while limiting off-target exposure.¹

Elizabeth Budde, MD, PhD, of City of Hope, who presented updated SUNMO data at ASCO 2026, described the combination as the first immune and targeted-based regimen pairing a bispecific T-cell engager with a CD79b-targeted ADC — a mechanistic rationale built on non-overlapping modes of action.⁴ "It's a little bit too early to say whether those patients can be cured with this regimen," Budde noted, "but I have patients now who I put on a previous phase 1/2 study testing the same regimen back in 2018 — some of them are still in complete remission 8 years, almost 10 years out."⁵

What would approval mean for patients?

Lunsumio IV and Lunsumio VELO are currently approved for third-line or later follicular lymphoma. If this sBLA is granted, it would represent an earlier-line indication — second-line and beyond in LBCL — for the subcutaneous formulation and would mark the first approval for the mosunetuzumab-plus-polatuzumab vedotin combination in this indication.¹

The combination's chemotherapy-free profile and outpatient administration format distinguish it from regimens that require inpatient coordination or referral to specialized centers, which prior research has identified as meaningful barriers to timely treatment in relapsed LBCL.¹ The urgency of that access question has been a consistent theme in expert commentary on bispecific combinations in DLBCL more broadly. Commenting on three-year survival data from the Phase 3 STARGLO study of another Roche CD20xCD3 bispecific, glofitamab, in R/R DLBCL, Jeremy Abramson, MD, director of the Jon and Jo Ann Hagler Center for Lymphoma at Mass General Brigham Cancer Institute and principal investigator of the STARGLO trial, noted that the data "underscore the meaningful benefit of [a bispecific combination] for patients after initial relapse, when fast and effective treatment is critical given the aggressive nature of this disease."⁶ While that comment referred to a distinct regimen, the clinical context — transplant-ineligible patients needing prompt, accessible therapy in the relapsed setting — is shared with the SUNMO trial population. Whether the practical attributes of the Lunsumio and Polivy combination translate into broader real-world access will depend on further post-approval experience.

References

1. FDA accepts supplemental Biologics License Application for Roche's Lunsumio and Polivy combination for people with relapsed or refractory large B-cell lymphoma. (2026 Jun 18). Roche. https://www.roche.com/media/releases/med-cor-2026-06-18
2. Sehn LH, Salles G. (2021 Mar 3). Diffuse large B-cell lymphoma. N Engl J Med. https://www.nejm.org/doi/full/10.1056/NEJMra2027612
3. Westin J, Zhang H, Kim W, et al. (2025 Dec 20). Mosunetuzumab plus polatuzumab vedotin in transplant-ineligible refractory/relapsed large B-cell lymphoma: primary results of the phase III SUNMO trial. J Clin Oncol. https://pubmed.ncbi.nlm.nih.gov/41037766/
4. Kim W, Westin J, Maruyama D, et al. (2026). Mosunetuzumab plus polatuzumab vedotin (Mosun-Pola) versus rituximab, gemcitabine and oxaliplatin (R-GemOx) in patients with relapsed/refractory large B-cell lymphoma: updated efficacy and safety from the phase 3 SUNMO study including in second-line versus third-line plus patient subgroups. Presented at: ASCO Annual Meeting; May 29–June 2, 2026; Chicago, IL. Abstract 7007. https://www.asco.org/abstracts-presentations/267937
5. Budde EL. (2026 Jun). Phase 3 SUNMO data show Mosun-Pola cuts progression risk over R-GemOx in large B-cell lymphoma. AJMC. https://www.ajmc.com/view/phase-3-sunmo-data-shows-mosun-pola-cuts-progression-risk-over-r-gemox-in-large-b-cell-lymphoma-elizabeth-budde-md-phd
6. Mirasol F. (2025 Dec 8). Roche drives industry shift with three-year lymphoma survival data. BioPharm International. https://www.biopharminternational.com/view/roche-drives-industry-shift-with-three-year-lymphoma-survival-data