MB-106

P1/2, N=53, Active, not recruiting, Fred Hutchinson Cancer Center | Trial completion date: Nov 2037 --> Mar 2039

P1/2, N=20, Terminated, Mustang Bio | N=287 --> 20 | Trial completion date: Sep 2026 --> Apr 2024 | Recruiting --> Terminated | Trial primary completion date: Sep 2026 --> Apr 2024; Business reasons

P=N/A, N=3, Terminated, Mustang Bio | N=331 --> 3 | Trial completion date: Jul 2041 --> Apr 2024 | Enrolling by invitation --> Terminated | Trial primary completion date: Apr 2041 --> Apr 2024; Business Reasons

P1/2, N=53, Active, not recruiting, Fred Hutchinson Cancer Center | Recruiting --> Active, not recruiting | Trial primary completion date: Nov 2024 --> Mar 2024

Following lymphodepletion (cyclophosphamide 300 mg/m2/day and fludarabine 30 mg/m2/day for 3 days), MB-106 is administered to patients with indolent B-cell NHL at one of two dose levels (DL): DL1, 3.3×106; and DL2, 1.0×107 cells/kg. Treatment with MB-106, a third generation CD20 targeting CAR-T, resulted in responses, including CRs, and CAR-T persistence in patients with R/R indolent NHL and was associated with favorable safety profile with no occurrence of Grade 3 or Grade 4 cytokine release syndrome and no ICANS of any grade. CRs have been observed in patients previously treated with CD19-targeted CAR-T in both this multicenter trial and the original single institution trial. Dosing is ongoing in the final dosing level (1.0×107 cells/kg) to establish the recommended Phase 2 dose for a planned pivotal trial in WM.

Lymphodepletion (LD) consists of cyclophosphamide + fludarabine...All 4 pts had BTKi refractory disease (2 ibrutinib, 1 acalabrutinib, 1 zanubrutinib)...One pt received bridging therapy with bendamustine after leukapheresis and before CAR-T infusion (3 DL3 and 1 DL2)... Early results of CD20 CAR-T therapy with MB-106 for BTKi-refractory WM/LPL suggest high efficacy and favorablesafety profile with no grade 3/4 CRS and no grade 2/3/4 ICANS. MB-106 has received orphan drug designation by the US FDA for WM, and a multicenter study is currently active in the US for WM and other B-NHLs. Enrollment also continues in this single institution study, and the results will be updated during the presentation.

Treatment with MB-106, a 3rd-generation CD20 targeting CAR-T, resulted in high ORR and CR rates and CAR-T persistence in FL pts and was associated with a favorable safety profile with no occurrence of Gr 3 or Gr 4 CRS and no ICANS of any grade. A multicenter trial for treatment of B-cell malignancies including FL is ongoing in the US.

P1/2, N=50, Recruiting, Fred Hutchinson Cancer Center | N=35 --> 50

P1/2, N=287, Recruiting, Mustang Bio | Not yet recruiting --> Recruiting

Chimeric antigen receptor T-cells (CAR-T) targeting CD19 are effective, and axicabtagene ciloleucel is currently approved by FDA for treatment of patients (pts) with relapsed FL, but toxicities like cytokine-release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) may limit its use...Lymphodepletion (LD) consists of cyclophosphamide (Cy) ± fludarabine (Flu)...Median time between leukapheresis and LD was 15 days (range: 9-21) and 2 pts received bridging therapy with lenalidomide (1) and high-dose corticosteroids (1)...Conclusion Treatment with MB-106, a third generation CD20 targeting CAR-T, resulted in high ORR and CR rates and CAR-T persistence in FL pts and was associated with favorable safety profile with no occurrence of Gr 3 or Gr 4 CRS and no ICANS event of any grade. A multicenter trial for treatment of B-cell malignancies including FL will start enrollment in 2022.

P1/2, N=287, Not yet recruiting, Mustang Bio

Lymphodepletion (LD) consists of cyclophosphamide (Cy) ± fludarabine (Flu)...Only 1 pt required tocilizumab and dexamethasone...Treatment with MB-106 has also resulted in high ORR and CR rates with ongoing remissions in all patients who achieved a CR. Enrollment is currently ongoing and the data will be updated at the time of presentation.