Long-Term Follow Up of Patients (pts) with High-Risk Chronic Lymphocytic Leukemia (CLL) Given Nonmyeloablative Allogeneic Hematopoietic Cell Transplantation (HCT).
Authors: Sorror Mohamed L. , Storer Barry , Sandmaier Brenda M. , Maris Michael B. , Shizuru Judith , Leis Jose , Agura Edward , Chauncey Thomas , Pulsipher Michael , McSweeney Peter , Wade James , Bruno Benedetto , Langston Amelia , Radich Jerry , Niederwieser Dietger , Blume Karl , Storb Rainer , Maloney David G. 
Published: April 2020

We previously reported 2-year overall survival (OS) of 60% among 64 pts given nonmyeloablative HCT (Sorror et al, JCO2005, 23: 3819). Here, we update our results on the initial 64 pts with median follow up of 5 (range:3–7) years and report on 18 additional pts with emphasis on: 1) long-term disease control, 2) resolution of chronic GVHD, and 3) outcomes of pts with poor-risk genomic features. Conditioning consisted of 2 Gy total body irradiation with or without fludarabine (90 mg/m2). Median age was 56 (range 42–72) years and median number of prior regimens was 4. Eighty-seven percent, 56%, and 41% of pts had fludarabine-refractory CLL, chemo-resistant disease at HCT, and unfavorable cytogenetics, respectively. Donors were related (n=52) or unrelated (n=30). The incidences of grades II, III, and IV acute GVHD were 39%, 14%, and 2% respectively, and chronic extensive GVHD was 51%. Overall disease response was seen in 70% of pts, and 55% achieved complete remission (CR). Estimated 5-years rates of non-relapse mortality (NRM), progression/relapse, OS, and progression-free survival (PFS) were 23%, 38%, 50%, and 39%, respectively (Table 1 shows outcomes by donor type). Overall, 42 patients are alive; 31 in CR, 4 in PR, 1 with stable disease, and 6 with relapse/progression. Among 14 responding pts tested and found to have molecular eradication of their disease, 2 died of NRM, 2 eventually relapsed, and 10 remained negative at a median of 6 years. Lymph node diameter &gt;5 cm was an independent risk factor for relapse (p=0.008) and PFS (p=0.01), while unfavorable cytogenetics (Table 2) were not (p=0.65 and 0.88, respectively). Among the pts who were alive at 5-years, 76% were without chronic GVHD while 24% received immunosuppression for chronic GVHD. Median performance status (PS) was 100% and 90% among pts without or with chronic GVHD, respectively. Nonmyeloablative HCT resulted in a median survival of 5 years for fludarabine-refractory CLL. Sustained molecular remissions and continuing resolution of chronic GVHD with good PS were observed in most pts with extended follow up. Nonmyeloablative HCT might change the natural history of CLL with unfavorable cytogenetics if considered earlier.

Table 1: Outcomes by donor type Donor At 5-years Related (n=52) Unrelated (n=30) p-value % % CR 48 67 0.04 NRM 22 24 0.97 Pgrossion/relapse 43 26 0.18 PFS 35 51 0.28 OS 49 51 0.57 Pts alive with chronic GVHD requiring immunosuppression 14 7 Table 2: Outcomes of pts with poor genomic features Abnormality (n) Pts alive Pts who died Median interval, years Median interval, years CR/PR/PD From Dx From HCT CR/PR/NE/PD From Dx From HCT PR indicates partial remission; PD, progression; Dx, diagnosis; and NE, not evaluated del 17p (7) 4/0/0 6.5 3.3 1/0/0/2 6.5 0.3 del 11q (7) 1/2/2 8.1 2.1 1/0/0/1 7.5 0.7 Tri 12 (7) 4/0/0 6.7 4.4 0/0/2/1 3.8 0.2 Complex (9) 4/0/0 11.4 5.7 0/1/0/4 10.5 3.5