Is Lumoxiti Approved for Hairy Cell Leukemia?
Yes, Lumoxiti (moxetumomab pasudotox-tdfk) is FDA-approved specifically for treating relapsed or refractory hairy cell leukemia (HCL) in adults who have received at least two prior systemic therapies, including a purine nucleoside analog.[1] It targets CD22 on leukemia cells, delivering a toxin that kills them.
How Does Lumoxiti Work in HCL?
Lumoxiti is an immunotoxin: a monoclonal antibody fused to a Pseudomonas exotoxin fragment. It binds CD22 (highly expressed in HCL), internalizes, and inhibits protein synthesis, leading to cancer cell death. Administered intravenously over 28-day cycles: 0.04 mg/kg Days 1, 3, 5 (cycle 1), then Days 1 and 3 (subsequent cycles), with premedication to manage capillary leak syndrome.[1]
Who Qualifies for Lumoxiti Treatment?
Eligible patients have HCL confirmed by bone marrow pathology, received ≥2 prior therapies (e.g., cladribine, pentostatin), and no active autoimmune disease or significant organ dysfunction. Not for frontline therapy or multiply relapsed cases without prior purine analogs.[1]
What Response Rates Show Effectiveness?
In the phase 3 SHP499 trial (86 patients), 75% achieved complete remission (CR), 41% durable CR (≥6 months without further treatment). Median duration of response: 22 months; progression-free survival: 16.7 months. Median overall survival not reached after 16 months follow-up.[1][2]
Common Side Effects and Risks
Capillary leak syndrome (53%, mostly grade 1-2; 2% fatal), nausea (77%), fatigue (65%), edema (63%), chills (60%), pyrexia (57%), headache (44%). Hemolytic uremic syndrome (13%), infections (38%). Requires hospitalization for first cycle; monitor albumin, weight, renal function.[1]
How Does Lumoxiti Compare to Standard HCL Treatments?
HCL standard: purine analogs (cladribine: 80-90% initial CR). Lumoxiti fills gap for refractory cases—higher CR (75% vs. 40-50% with pentostatin rechallenge). No head-to-head trials vs. ibrutinib (40% ORR in refractory HCL) or venetoclax (emerging).[2][3] Shorter-term data than chemo.
Availability, Cost, and Access
AstraZeneca markets Lumoxiti (launched 2018). List price ~$28,000 per cycle (3 doses); 2-6 cycles typical. Covered by Medicare Part B; patient assistance via AstraZeneca Access 360°.[4] Discontinued in some markets post-2021 due to manufacturing/supply issues, but available via expanded access in U.S.[5]
When Did Approval Happen and What's the Patent Status?
FDA accelerated approval October 2018, full March 2020 based on durable CR rate.[1] Patents expire 2032-2034 (composition, method of use); no active challenges listed.[6]
[1]: FDA Lumoxiti Label
[2]: NEJM: SHP499 Trial
[3]: Blood: HCL Review
[4]: AstraZeneca Pricing
[5]: FDA Expanded Access
[6]: DrugPatentWatch: Lumoxiti