Background
Retrospective analysis of prospectively treated patients. N=76 patients with T-cell prolymphocytic leukemia (T-PLL) treated with alemtuzumab (anti-CD52 monoclonal antibody) at a single UK center (Royal Marsden), the largest published T-PLL series. T-PLL is an aggressive mature T-cell leukemia with mOS ~12 months on conventional chemotherapy. Alemtuzumab (IV and/or subcutaneous) was evaluated as frontline and salvage therapy, with allogeneic SCT pursued in eligible responders. Published Blood 2011.
Interventions and follow up
Regimen: Alemtuzumab 30 mg IV three times weekly for up to 12 weeks (some patients subcutaneous) — T-cell prolymphocytic leukemia
Primary endpoint: ORR, CR rate, OS
mFollow up: NR (retrospective series)
Primary endpoint: ORR, CR rate, OS
mFollow up: NR (retrospective series)
Results
ORR: 76% (58/76)
CR rate: 39% (30/76)
mOS (all patients): 21 months
mOS (allogeneic SCT recipients): Not reached (5-yr OS ~36%)
mOS (CR without SCT): 14.8 months
mOS (historical CHOP-based chemotherapy): ~7.5 months
CR rate: 39% (30/76)
mOS (all patients): 21 months
mOS (allogeneic SCT recipients): Not reached (5-yr OS ~36%)
mOS (CR without SCT): 14.8 months
mOS (historical CHOP-based chemotherapy): ~7.5 months
Adverse events
Infusion/Hematologic: Infusion reactions any grade 53% (mostly first IV doses; premedication required); grade ≥3 neutropenia 30%; autoimmune cytopenias (ITP, AIHA) 8%
Infections: CMV reactivation grade ≥3 46% (prophylaxis + weekly PCR required); grade ≥3 non-CMV infections 37%; prolonged CD4+/CD8+ lymphopenia; two treatment-related deaths (infections)
Infections: CMV reactivation grade ≥3 46% (prophylaxis + weekly PCR required); grade ≥3 non-CMV infections 37%; prolonged CD4+/CD8+ lymphopenia; two treatment-related deaths (infections)
Conclusions
Alemtuzumab achieved a 76% ORR and 39% CR rate in T-PLL — far superior to historical CHOP-based chemotherapy — and improved median OS to 21 months. Allogeneic SCT in responders provided the best long-term outcomes (~36% 5-year OS), establishing alemtuzumab induction followed by alloSCT as the only potentially curative strategy.
Key Limitations
Retrospective, single-center: No randomized comparator; selection bias toward fitter patients
IV vs SC heterogeneity: SC dosing reduced acute infusion reactions but yielded lower response rates in some series
Drug access: Alemtuzumab was withdrawn from oncology markets and is available only via restricted access programs
IV vs SC heterogeneity: SC dosing reduced acute infusion reactions but yielded lower response rates in some series
Drug access: Alemtuzumab was withdrawn from oncology markets and is available only via restricted access programs
Clinical Context
IV alemtuzumab is the standard induction therapy for T-PLL and is endorsed in expert consensus (T-PLL International Study Group criteria), with consolidative allogeneic SCT for eligible responders given inevitable relapse. Alemtuzumab was withdrawn commercially for oncology and is obtained through restricted-access programs. Novel agents (venetoclax, BCL-2-directed and JAK/STAT-targeted approaches) are under investigation for relapsed disease.