Cellectis lasme-cel wins FDA RMAT tag ahead of Phase 2 interim read

Cellectis has received Regenerative Medicine Advanced Therapy (RMAT) designation from the US Food and Drug Administration for lasme-cel, its allogeneic CAR-T candidate targeting CD22-positive relapsed or refractory B-cell acute lymphoblastic leukaemia (r/r B-ALL). The designation, granted in June 2026, was based on Phase 1 data from the BALLI-01 trial and reflects the agency's assessment that the therapy may address a substantial unmet medical need. A first interim analysis from the pivotal Phase 2 cohort is expected in Q4 2026, making the coming months the most significant near-term inflection point for the programme.

Full Phase 1 data presented at the European Hematology Association Annual Congress in June showed a 100% overall response rate across seven patients in the target Phase 2 population, all of whom were in third line or beyond and had received a median of five prior lines of therapy. Complete remission or complete remission with incomplete count recovery was achieved in 57% of that group, with 75% of those responders testing minimal residual disease (MRD)-negative. All responding patients went on to haematopoietic stem cell transplantation. The safety readout showed grade 3 or higher cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome each in 4% of treated patients, with all events resolving. The small patient numbers warrant caution, as Cellectis itself acknowledges in its forward-looking statements, but the profile is broadly competitive with existing allogeneic approaches.

Eti-cel and the NHL programme

Cellectis also presented translational data from its NATHALI-01 Phase 1 trial of eti-cel in relapsed or refractory non-Hodgkin lymphoma at EHA 2026. As of a February 2026 data cut, 14 patients had been treated across three dose levels, with the optimal dose cohort of eight patients showing an 88% overall response rate and a 63% complete response rate. Notably, 93% of enrolled patients had previously received CD19-directed CAR-T therapy, indicating a heavily pre-treated and difficult-to-treat population. Translational findings suggested that higher alemtuzumab exposure during lymphodepletion correlated with improved eti-cel expansion and response rates. The company is evaluating weight-based alemtuzumab dosing and subcutaneous low-dose interleukin-2 to optimise the regimen. Full Phase 1 data are expected in Q4 2026.

Market context and competitive landscape

The allogeneic CAR-T sector has faced a turbulent few years. Several early developers reported disappointing efficacy relative to autologous therapies, and the field narrowed considerably through the early 2020s. Cellectis occupies a distinctive position: it retains in-house gene-editing and manufacturing capabilities at sites in Paris and Raleigh, North Carolina, and its technology underpins partnered programmes at Allogene, which in July 2026 reported RMAT and Fast Track designations for cema-cel in large B-cell lymphoma. The Allogene pipeline, built partly on Cellectis intellectual property, provides a read-across to the underlying platform's commercial potential even as Cellectis advances its proprietary candidates.

RMAT designation, while not a guarantee of approval, opens an expedited pathway including more frequent FDA interaction, rolling review eligibility, and potential for accelerated approval. For a company of Cellectis's scale, with $169 million in cash and equivalents extending runway into Q4 2027, the designation adds regulatory optionality at a point when the Phase 2 interim read is imminent. R&D spending rose to $52.2 million in the first half of 2026 from $45.0 million in the same period a year earlier, driven by higher clinical development costs across BALLI-01 and NATHALI-01, while revenues fell to $14.5 million from $30.2 million, largely reflecting reduced activity under the AstraZeneca joint research collaboration. The net loss for the first half narrowed marginally to $39.6 million from $41.9 million in H1 2025.

Investors will focus on the Q4 2026 interim analysis for BALLI-01 as the decisive read on whether lasme-cel can sustain the early efficacy signals in a broader pivotal cohort and whether the programme is on a trajectory towards a regulatory filing.