Mucosal injury in patients undergoing hematopoietic progenitor cell transplantation: new approaches to prophylaxis and treatment.

Hematopoietic progenitor cell transplantation is often associated with severe mucosal toxicity. The need for parenteral analgesics and parenteral nutrition are evidence of the severity of the problem in individual patients. However, the increased risk for systemic infection related to bacteremia associated with the breakdown of mucosal barriers is a significant cause of morbidity and mortality as well. There is a multitude of grading scales, demonstrating the lack of consensus among clinicians in this area. Multiple agents have been used prophylactically and therapeutically to address mucositis. While efforts have been less successful in the past, the advent of newer agents including amifostine, keratinocyte growth factor, transforming growth factor beta and interleukin-11 provides hope that this toxicity will be significantly decreased in the near future.

Activity of single-agent melphalan 220-300 mg/m2 with amifostine cytoprotection and autologous hematopoietic stem cell support in non-Hodgkin and Hodgkin lymphoma.

High-dose chemotherapy using melphalan (HDMEL) is an important component of many conditioning regimens that are given before autologous hematopoietic stem cell transplantation (AHSCT). In contrast to the situation in myeloma, and to a lesser degree acute leukemia, only a very limited published experience exists with the use of HDMEL conditioning as a single agent in doses requiring AHSCT for lymphoma, both Hodgkin lymphoma (HL) and especially non-Hodgkin lymphoma (NHL). Thus, we report results of treating 26 lymphoma patients (22 with NHL and four with HL) with HDMEL 220-300 mg/m(2) plus amifostine (AF) cytoprotection and AHSCT as part of a phase I-II trial. Median age was 51 years (range 24-62 years); NHL histology was varied, but was aggressive (including transformed from indolent) in 19 patients, indolent in two patients and mantle cell in one. All 26 patients had been extensively treated; 11 were refractory to the immediate prior therapy on protocol entry and two had undergone prior AHSCT. All were deemed ineligible for other, 'first-line' AHSCT regimens. Of these 26 patients, 22 survived to initial tumor evaluation on D +100. At this time, 13 were in complete remission, including four patients who were in second CR before HDMEL+AF+AHSCT. Responses occurred at all HDMEL doses. Currently, seven patients are alive, including five without progression, with a median follow-up in these latter patients of D +1163 (range D +824 to D +1630); one of these patients had a nonmyeloablative allograft as consolidation on D +106. Conversely, 14 patients relapsed or progressed, including five who had previously achieved CR with the AHSCT procedure. Two patients, both with HL, remain alive after progression; one is in CR following salvage radiotherapy. Six patients died due to nonrelapse causes, including two NHL patients who died while in CR. We conclude that HDMEL+AF+AHSCT has significant single-agent activity in relapsed or refractory NHL and HL. This experience may be used as a starting point for subsequent dose escalation of HDMEL (probably with AF) in established combination regimens.

Nonmyeloablative conditioning allows for more rapid T-cell repertoire reconstitution following allogeneic matched unrelated bone marrow transplantation compared to myeloablative approaches.

Nonmyeloablative pretransplantation conditioning regimens have resulted in durable engraftment of allogeneic hematopoietic stem cells. In contrast to conventional fully myeloablative approaches, nonmyeloablative regimens are associated with a marked reduction of morbidity and mortality in the early posttransplantation period. Consequently, such reduced-intensity transplantation approaches can be used in older and frailer patients who would not tolerate fully ablative regimens. However, it is currently unclear how this radically different transplantation strategy affects immunological reconstitution. To address this important issue, we used T-cell receptor Vbeta spectratype analysis to examine the distribution of complementarity-determining region 3 (CDR3)-size bands as a measure of the complexity of the redeveloping T-cell repertoire. For this study, we evaluated the T-cell repertoire of 9 patients receiving T-cell replete, matched unrelated donor transplants following fully ablative or nonmyeloablative conditioning regimens. All 4 of the myeloablative and 2 of the nonmyeloablative patients received bone marrow, whereas 3 other nonmyeloablative patients received peripheral blood stem cells. The results of the spectratype analysis demonstrated that the patients who received nonmyeloablative conditioning together with either bone marrow or peripheral blood stem cells exhibited more rapid reconstitution of T-cell repertoire complexity.

Amifostine and autologous hematopoietic stem cell support of escalating-dose melphalan: a phase I study.

This study was conducted to define a new maximum tolerated dose and the dose-limiting toxicity (DLT) of melphalan and autologous hematopoietic stem cell transplantation (AHSCT) when used with the cytoprotective agent amifostine. Fifty-eight patients with various types of malignancy who were ineligible for higher-priority AHSCT protocols were entered on a phase I study of escalating doses of melphalan beginning at 220 mg/m(2) and advancing by 20 mg/m(2) increments in planned cohorts of 4 to 8 patients until severe regimen-related toxicity (RRT) was encountered. In all patients, amifostine 740 mg/m(2) was given on 2 occasions before the first melphalan dose (ie, 24 hours before and again 15 minutes before). AHSCT was given 24 hours after the first melphalan dose. Melphalan was given in doses up to and including 300 mg/m(2). Hematologic depression was profound, although it was rapidly and equally reversible at all melphalan doses. Although mucosal RRT was substantial, it was not the DLT, and some patients given the highest melphalan doses (ie, 300 mg/m(2)) did not develop mucosal RRT. The DLT was not clearly defined. Cardiac toxicity in the form of atrial fibrillation occurred in 3 of 36 patients treated with melphalan doses >/=280 mg/m(2) and was deemed fatal in 1 patient given melphalan 300 mg/m(2). (Another patient with a known cardiomyopathy was given melphalan 220 mg/m(2) and died as a result of heart failure but did not have atrial fibrillation.) Another patient given melphalan 300 mg/m(2) died of hepatic necrosis. The maximum tolerated dose of melphalan in this setting was thus considered to be 280 mg/m(2), and 27 patients were given this dose without severe RRT. Moreover, 38 patients were evaluable for delayed toxicity related to RRT; none was noted. Tumor responses have been noted at all melphalan doses and in all diagnostic groups, and 21 patients are alive at median day +1121 (range, day +136 to day +1923), including 16 without evidence of disease progression at median day +1075 (range, day +509 to day +1638). Amifostine and AHSCT permit the safe use of melphalan 280 mg/m(2), an apparent increase over the dose of melphalan that can be safely administered with AHSCT but without amifostine. Further studies are needed not only to confirm these findings, but also to define the antitumor efficacy of this regimen. Finally, it may be possible to evaluate additional methods of further dose escalation of melphalan in this setting.