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In‐vivo purging of the circulating clonal T‐cells with Alemtuzumab prior to autologous peripheral blood hematopoietic cell mobilization and transplantation

Year: 2011

Type: article

Abstract: Peripheral T-cell lymphomas (PTCL) are a diverse group of aggressive lymphoid malignancies that comprise 10–15% of non-Hodgkin lymphomas (NHL) (Morton et al, 2006). Complete remission (CR) can be obtained in 40–60% of patients treated with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) or CHOP-like chemotherapy. However, relapse ensues in the majority of patients, with median overall survival (OS) of <2 years and 5-year survival <30% (Armitage et al, 2008). To improve outcomes, high dose chemo(radio)therapy (HDT) with autologous stem cell transplantation (ASCT) has been attempted as consolidation after primary therapy. Corradini et al (2006) and Mercadal, et al (2008) reported 27% 12-year and 30% 4-year disease free survival, respectively. These results, however, were not significantly superior to the historic long-term survival reported in patients treated with chemotherapy alone. Progression-free survival in PTCL after ASCT is significantly better in patients achieving CR prior to HDT, hence, it is reasonable to hypothesize that relapses after ASCT may result from incomplete eradication of endogenous tumour cells or from infusion of tumour-contaminated stem cell product. In-vivo purging could be attempted to minimize relapses after HDT-ASCT. Use of Rituximab to purge circulating malignant B-cells prior to haematopoietic stem cell harvest was shown to improve outcomes in B-cell lymphomas (Arcaini et al, 2008). Alemtuzumab (Campath-1H) is a chimeric monoclonal anti-CD52 antibody that has shown activity in eliminating minimal residual disease in the peripheral blood and bone marrow in chronic lymphocytic leukaemia (Montillo et al, 2006). Considering its high activity in T-cell malignancies, we hypothesized that alemtuzumab could be an effective in-vivo purging agent in patients with circulating clonal T-cells prior to undergoing stem cell harvest and HDT-ASCT. We report the case of a 72-year-old female with stage III PTCL-NOS (International Prognostic Index [IPI] score of 4) in first CR with persistent circulating malignant T-cell clone who received three consecutive doses of alemtuzumab with resultant clearance of malignant cells from peripheral blood and successful harvest of uncontaminated stem cell product. Initial therapy consisted of six cycles of dose-adjusted EPOCH (infusional etoposide, doxorubicin, vincristine, cyclophosphomide and prednisone) without significant complications. Post-treatment computerized tomography-positron emission tomography demonstrated CR. Considering the very poor prognosis in T-cell lymphomas with high-risk IPI (5-year OS <10%), it was decided to proceed with HDT-ASCT. During monitoring of CD34+ cell levels for initiation of stem cell harvest, clonal T-cell population was discovered in the patient’s peripheral blood. The immunophenotypic profile and T cell receptor gene rearrangement type was identical to original malignant clone. The clone expressed CD52. Three intravenous doses of alemtuzumab, 3, 10 and 30 mg, respectively, were delivered on alternating days. Flow cytometry was performed on aliquots of stem cell product and peripheral blood using antibody cocktails described previously (Wood, 2006) and revealed reduction in circulating clonal T-cells from 0·7% to 0·0005% after the first infusion and complete clearance of circulating tumour cells after the second (Fig 1). Apheresis on days 9 and 10 after the last dose of alemtuzumab yielded 8·18 × 106 CD34+ cells/kg. Analysis of leucocyte subsets within the graft demonstrated 0·26% blasts (CD34+), 35·1% maturing neutrophilic forms, 63·5% monocytes, 0·26% dendritic cells, and 0·13% lymphocytes. The lymphocytes consisted of 16·1% B cells (CD19+), 80·5% T cells (CD3+), with a CD4:CD8 ratio of 0·084, and 3·4% NK cells (CD3−, CD7+) (Fig 2). There was no evidence of T-NHL by flow cytometry or molecular studies (Fig 1). Biological Response to Alemtuzumab. (A) Peripheral blood (PB) flow cytometry prior to administration of Alemtuzumab. An abnormal T cell population is highlighted in magenta and accounts for 0·7% of the white blood cells. (B) Flow cytometry of the PB at 2 d post-therapy. Only a single event is noted with an immunophenotype similar to the patient’s neoplasm, thus, if present, abnormal cells represent <0·0005% of the white blood cells. (C) Flow cytometry of the PB on day 4 post-therapy. No abnormal cells are detectable in this sample. (D) Flow cytometry of a stem cell product showing no evidence of involvement by T cell lymphoma. Stem cell product composition. (A) Shows all viable cells. These consist predominantly of monocytes (pink), with fewer granulocytes (green), and a paucity of lymphoid cells (blue, highlighted by arrow). (B) Gate identifying CD34+ cells (highlighted in red) among the white blood cells. (C) The majority of the myelomonocytic cells are mature, CD14 positive, monocytic cells (pink) with fewer, CD16 positive, mature myeloid cells (green). (D) Photograph of a Wright Giemsa stained cytospin prepared from the stem cell product taken at 640× magnification. The patient received HDT with BEAM [BCNU (carmustine), etoposide, cytarabine and melphalan] regimen and ASCT. Toxicities of HDT included mucositis, fatigue, asthenia, dehydration, neutropenic fever, pancytopenia. Engraftment of platelets was achieved on day 12 and neutrophils on day 13. On day 27 post-transplantation increasing cytomegalovirus (CMV) and BK viraemia (associated with haemorrhagic cystitis) were detected in the peripheral blood of the patient. She was treated with intravenous ganciclovir and supportive care including bladder irrigation. On day 64, the patient presented with fevers, chills and left lower quadrant abdominal pain. Esophagogastroduodenoscopy and biopsy revealed adenovirus-associated gastroenteritis and concurrent viraemia, 570 000 copies/μl, that persisted despite therapy with cidofovir. Further infections ensued on day 111 including Clostriduim-difficile colitis and parainfluenza. On day 156 post-transplant, the patient succumbed to multi-organ failure due to infectious complications. The usefulness of HDT and ASCT in chemosensitive PTCL patients in first remission remains unclear and no randomized trials have been performed to date. Patients achieving CR prior to ASCT might have superior outcomes (Reimer et al, 2009). It is reasonable to speculate that persistence of the malignant clone at the time of stem cell harvest might be one of the mechanisms of relapse after transplantation. Alemtuzumab, chimeric monoclonal anti-CD52 antibody, has high activity in T-cell malignancies and in eliminating minimal residual disease in the peripheral blood and bone marrow (Montillo et al, 2006). It is reasonable to consider this agent for in-vivo purging prior to stem cell collection in patients with T-cell lymphomas/leukaemias that express CD52. Treatment with Alemtuzumab, however, is associated with significant immunosuppression from severe depletion of both the T-cell and B-cell lymphocytes (Osterborg et al, 2009). In the setting of HDT, CD34 selection of the autograft has been reported to result in significant increase of CMV-related events and risk of other infections after ASCT (Holmberg et al, 1999). Serious infections that developed in our patient after HDT-ASCT are in agreement with these reports and call for further investigation of the proper dosing, timing and anti-microbial prophylaxis in this setting. We hypothesized and demonstrated the feasibility and effectiveness of alemtuzumab in-vivo purging prior to PBSC harvest in a patient with PTCL-NOS who achieved radiographic CR yet had a persistent circulating malignant clone. The treatment lead to rapid clearance of clonal T-cells and there was no adverse effect on CD34+ cell yield or engraftment. However, the profound lymphodepletion and its sequelae necessitate further refinement of this strategy. AS and T-AL performed research, analyzed data, wrote the paper. SC analyzed pathology. AS performed research. DM analyzed data. LH analyzed data, performed research and wrote the paper. AKG analyzed data. Research Support: NIH grants P01CA44991, and a donation from Frank and Betty Vandermeer AKG is a Scholar in Clinical Research of the Leukemia and Lymphoma Society.

Source: British Journal of Haematology

DOI: 10.1111/j.1365-2141.2011.08619.x