Frontline Combined Chemoimmunotherapy with Fludarabine, Cyclophosphamide, Alemtuzumab and Rituximab (CFAR) in High-Risk Chronic Lymphocytic Leukemia.

Abstract

Abstract 208 Background:Combined chemoimmunotherapy with fludarabine, cyclophosphamide and rituximab (FCR) has excellent clinical activity as frontline therapy for patients (pts) with chronic lymphocytic leukemia (CLL). In a subset of pts who exhibited high-risk features, such as serum beta-2 microglobulin (B2M) ≥4 mg/L; the complete remission (CR) was lower and time to progression (TTP) and overall survival (OS) were shorter; therefore characterizing these pts as high-risk. Alemtuzumab (A) has activity as a single-agent and in combination with F in pts with relapsed/refractory CLL. To improve the CR and OS for pts with high-risk CLL, we added A to the FCR regimen (CFAR) as frontline therapy in a Phase II clinical trial. Methods:All pts who met NCI-WG criteria to initiate therapy, were < 70 years and had a B2M ≥4 mg/L were eligible for the study. Frontline CFAR consisted of C-200 mg/m2 D3-5, F-20mg/m2 D3-5, A-30mg IV D1,3,5, and R-375–500 mg/m2 D2. Courses were repeated every 28 days for a total of 6 courses. All pts received pegylated filgrastim 6mg SC with each course of therapy. All pts received allopurinol for tumor lysis prophylaxis. Antibiotic prophylaxis with TMP/SMX DS and valacyclovir or valganciclovir was also given to all pts. CMV antigenemia was monitored before each course. Results:A total of 60 pts were enrolled from July 2005 through August 2008 (Table). One pt was lost to follow-up. The median age was 59 yrs (range 42–69) and 44 (75%) were male. Median B2M was 5.1 mg/L (4–11.6); HGB was 11.5gm/dL (5.5–15.1); PLT was 139 k/μL(41–446); WBC was 100k/μL (5–665); ALC was 92k/μL (4–619); and 30 pts (51%) were Rai stage III-IV. The median number of courses administered was 4 (2–6); reasons for not completing 6 courses included delayed recovery of counts (18), infection (8), AIHA (4), treatment failure (3) and pt. choice (2). CR was achieved in 70%, nPR in 3%, PR in 18%, and 7% pts did not respond, leading to an ORR of 92% (Table). There was no significant correlation between CR or OR with Rai Stage, IgVH mutation status, FISH status, ZAP70 and CD38 expression. After a median follow-up of 24 months (3–49), 19(32%) pts have progressive disease. Patients with 17p deletion and unmutated IgVH had significantly shorter TTP as shown in the >Table. Eleven (19%) pts have died: 4 with disease progression after achieving CR; 2 who did not respond; 2 with Richter's transformation; 1 transformed into AML; 1 due to metastatic lung cancer; and 1 due to severe pneumonia 8 months after achieving CR. Grade 3/4 neutropenia and thrombocytopenia occurred in 31% and 13% courses. Major infections, including pneumonia and sepsis, were reported for 10(17%) pts. Minor infectious such as bronchitis, urinary tract infections and herpes zoster were reported for 15(25%) pts. In a historic cohort of high-risk pts treated with FCR, grade 3/4 neutropenia and thrombocytopenia occurred in 31% and 10% courses; and major and minor infections were seen in 15% and 23% pts respectively, all comparable to that seen with frontline CFAR. A-associated infusion reactions occurred in 42 (71%) pts. CMV reactivation occurred in 7 (12%) pts, all of whom were on valacyclovir prophylaxis. There was 1 death due to CMV pneumonia; all other episodes of CMV reactivation were promptly treated with valaganciclovir leading to resolution of fever and/or antigenemia. The median OS for all pts has not been reached (49+mo) and the median TTP is 38 months.Patient CharacteristicN%CR%ORTTP (mo)All Evaluable59709238Age<60 yrs3370883261–70 yrs267310038SexMale44669132Female158710039+Rai StageI– II29729332III–IV30709342+ECOG PS0136985321–246719638WBC (x 109/L)≤ 5017708842+51–15025729232>150177010028β2-microglobulin (mg/L)4–5.0257210038>5.034708842+IgVHMutated (>2%)207010042+*Unmutated (<2%)37739233*Cytogenetics (FISH)Del 17p14577818¶Del 11q10809027¶Trisomy 12159310042+None95510042+Del 13q (sole)116410042+CD 38 expression≤ 30%38639538>30%21869028ZAP 70Positive (≥20%)33578232Negative (<20%)169410042+*p-value 0.01;¶p-value 0.001; + = median not reached Conclusion:CFAR is an active frontline regimen in high-risk pts with CLL. Although CR rates in pts with other high-risk features such as 17p deletion and unmutated IgVH were >50%, TTP was significantly shorter for these pts than for pts without these features. With current follow-up, OS, TTP, infectious complications and grade 3/4 hematologic toxicity are comparable to historic high-risk pts treated with FCR. Disclosures:Keating:Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees. Wierda:Genentech: Consultancy, Honoraria; Genzyme: Research Funding.