M Cavo, G Bandini, M Benni, A Gozzetti, S Ronconi, G Rosti, E Zamagni, RM Lemoli, A Bonini, A Belardinelli, MR Motta, S Rizzi and S Tura

Transcription

1 Bone Marrow Transplantation, (1998) 22, Stockton Press All rights reserved /98 $12. High-dose busulfan and cyclophosphamide are an effective conditioning regimen for allogeneic bone marrow transplantation in chemosensitive multiple myeloma M Cavo, G Bandini, M Benni, A Gozzetti, S Ronconi, G Rosti, E Zamagni, RM Lemoli, A Bonini, A Belardinelli, MR Motta, S Rizzi and S Tura Institute of Hematology and Medical Oncology Seràgnoli, University of Bologna, Italy Summary: The present clinical trial was undertaken to investigate the toxicity and antimyeloma activity of busulfan (BU) and cyclophosphamide (CY) at the maximum tolerated doses of, respectively, 16 mg/kg and 2 mg/kg (BU-CY 4) as conditioning therapy for allogeneic bone marrow transplantation (BMT) in 19 consecutive patients with multiple myeloma (MM). Twelve (63) had failed to respond to prior chemotherapy, while the remaining 37 had chemosensitive disease. No life-threatening or fatal regimen-related complications were observed. The incidence of veno-occlusive disease of the liver was zero according to Jones criteria and 21 according to McDonald s system. Transplant-related mortality was 37. Using stringent criteria, the frequency of complete remission (CR) was 42 among all patients and 53 among those who could be evaluated. With a median follow-up of 21 months for all patients and 66 months for survivors, the actuarial probability of survival and event-free survival at 4 years from BMT was 26 (95 CI: 7 46) and 21 (95 CI: 3 39), respectively. A more favorable outcome of transplantation was observed in the subgroup of patients with chemosensitive disease who had a transplant-related mortality of 14, an overall CR rate of 86 (95 CI: 49 97) and a 4-year projected probability of event-free survival of 57 (95 CI: 2 93). Four of these patients are currently alive in continuous CR after 54, 66, and 94 months, respectively. It is concluded that BU-CY 4 as conditioning for allogeneic transplantation for MM is associated with acceptable morbidity and relatively low mortality. This regimen exerts substantial antimyeloma activity, resulting in a high CR rate and durable responses, especially in patients with chemosensitive disease. Long-lasting remission and probable cure is possible following allogeneic stem cell transplantation for MM. Keywords: busulfan; cyclophosphamide; allogeneic bone marrow transplantation; multiple myeloma Correspondence: Dr M Cavo, Institute of Hematology and Medical Oncology Seràgnoli, University of Bologna, via Massarenti 9, 136, Bologna, Italy. Received 1 November 1997; accepted 1 February 1998 Allogeneic bone marrow transplantation (BMT) has been used since the early 19s for the treatment of MM and was initially pionereed in patients with advanced disease. 1 5 These pilot studies 1 3 demonstrated that the procedure was feasible and effected increased antitumor response, even after prior unresponsiveness to conventional chemotherapy. However, transplant-related morbidity and mortality were high, partly reflecting the poor clinical condition of most of the patients and the advanced phase of their disease at the time of BMT. 4 6 For this reason, in later years efforts were directed at improving the results by a more accurate selection of patients and earlier timing of transplantation. 7,8 In addition, attempts to decrease transplant-related mortality included the use of more effective methods of prevention of graftversus-host disease (GVHD) 7 and investigation of conditioning regimens not including total body irradiation (TBI). Among these latter, experience with the combination of busulfan (BU) with cyclophosphamide (CY) has been reported by several groups, albeit at varying doses and generally in small numbers of patients. 9,1 On the basis of these considerations, we began a pilot clinical trial in 1989 aimed at investigating the toxicity and activity of BU and CY administered at the maximum tolerated doses of, respectively, 16 mg/kg and 2 mg/kg (BU- CY 4) in preparation for allogeneic BMT for patients with MM. The results of this study are reported with a minimum follow-up period for survivors of 4 years. Patients and methods Patient selection Between April 1989 and November 1992, 19 consecutive MM patients with a confirmed diagnosis of overt, symptomatic MM 11 entered the protocol study. Patients were eligible for allogeneic BMT if they were less than 55 years old and had histocompatible sibling donors. Additional criteria also included a Karnofsky score 5 and adequate function of the heart, lungs, liver and kidneys (creatinine clearance 5 ml/min) before marrow transplantation. Patient characteristics Table 1 lists the main characteristics of the patients at diagnosis and at BMT. At transplant, seven patients were less

2 28 Table 1 Patient characteristics at diagnosis and at BMT Diagnosis BMT Median age (range) (years) 43 (33 47) (36 5) Sex (male/female) Median interval diagnosis BMT 19 (range) (months) (1 98) Durie and Salmon stage () I 6 (31) 1 (5) II 3 (16) 6 (32) III 1 (53) 12 (63) Median 2M (range) (mg/l) ( ) ( ) Disease status Responsive (1/ 2 lines of CHT) 7 (2/5) Stable refractory (1/ 2 lines of CHT) 8 (/8) Progressive (1/ 2 lines of CHT) 4 (3/1) than years old, while seven were more than 45 years of age. Only three patients were transplanted within 1 year of diagnosis. Seven patients (of whom six were females and six had advanced disease both at diagnosis and at transplant) had responded favorably ( 5 tumor reduction) to prior conventional chemotherapy administered over a median of 2 months (range 11 35). In two of these patients serum M protein was undetectable by routine electrophoresis. Out of the remaining 12 patients, eight had stable refractory disease after two to three lines of chemotherapy with alkylating agents and anthracycline-containing regimens administered over a median of 23 months (range 1 98), while four patients had progressive MM (see response criteria section). Conditioning regimen The BU-CY regimen consisted of oral BU at the daily dose of 4 mg/kg (in four divided doses, each of 1 mg/kg) on each of 4 consecutive days (total dose, 16 mg/kg), and CY at the daily dose of 5 mg/kg intravenously (i.v.) for 4 consecutive days (total dose, 2 mg/kg). Graft-versus-host disease (GVHD) prophylaxis Sixteen patients received a combination of i.v. cyclosporine (CsA) and i.v. methotrexate (MTX) as prophylaxis for acute GVHD. T depletion of donor marrow with the monoclonal antibody Campath 1 was performed in three patients. Two of these patients also received i.v. CsA. CsA was administered at a daily dose of 3 5 mg/kg, starting the day before marrow infusion. Oral CsA was substituted for i.v. when tolerated, usually starting on day 28, and was continued for 1 year, with progressive tapering of the dose after 6 months. The schedule for i.v. MTX administration was the following: 15 mg/m 2 on day 1 and 1 mg/m 2 on days 3, 6 and 11. Regimen-related toxicity Regimen-related toxicity was graded from the day of BMT to day using a previously described system. 12 The WHO classification 13 was also used to assess the severity of oropharyngeal mucositis and hemorrhagic cystitis. Diagnosis of veno-occlusive disease of the liver (VOD) was established according to Jones criteria 14 which included jaundice plus at least two of the following signs: painful hepatomegaly, ascites or weight gain exceeding 5 of baseline value. Liver toxicity not related to acute GVHD or hepatitis was recorded by analyzing the degree of bilirubin increase compared with the basal value and its association with, or absence of, an increase in body weight. Supportive care measures Hemorrhagic cystitis prophylaxis was with sodium 2-mercaptoethane sulfonate (mesna), administered at 12 of the total dose of CY. Three l/m 2 of dextrose were also infused during CY administration and continued for 24 h after CY ceased. Bladder irrigation was not performed routinely. Oral clorazepam ( mg twice daily) was given to reduce the likelihood of seizures during BU administration. Other supportive care measures included prophylactic acyclovir ( mg/kg/daily i.v. until the 4th week and then 12 mg orally until the 8th month). All blood products were leukocyte-depleted by filtration and irradiated with 2 Gy. Response criteria The first evaluation of response to BMT was carried out on day and consisted of serum and/or urine M component measurement and bone marrow aspiration. Patients were considered to be in complete remission (CR) if they experienced the disappearance of serum and/or urine M component by immunofixation analysis on at least two occasions, 2 months apart, and had less than 5 residual plasma cells in the bone marrow. Resolution of prior osteolytic lesions and normalization of polyclonal serum immunoglobulin levels were not required for definition of CR. Criteria for partial remission included a 5 or more decrease in serum M protein concentration, with less than.2 g/day of urinary light chain excretion. Patients not fulfilling any of the above-mentioned criteria were classified as nonresponders. After BMT, criteria for progressive disease included the reappearance of M protein in a complete responder or any of the following in a partial responder: (1) 5 increase in serum M protein level; (2) increase in urinary light chain output; (3) increase in number and extent of osteolytic lesions. Statistical analysis The rate of relapse or progression was evaluated in patients who were assessable for response to BMT. Actuarial risk for event (death or relapse/progression) was calculated by the method of Kaplan and Meier. 15 Patients were censored for event-free survival if alive and free from relapse or disease progression by the end of follow-up. Curves for eventfree survival and overall survival were plotted according to

3 the method of Kaplan and Meier and were compared by the log-rank test. 16 The latest follow-up for all patients was on June Results Engraftment Engraftment after BMT occurred in 18 patients who achieved an absolute granulocyte count /l at a median of 18 days (range 12 22). Unsupported platelet counts /l were recorded in 17 patients at a median of 2 days (range 11 46). One patient who received a T cell-depleted marrow had graft failure and died on day 36 of cerebral hemorrhage. One other patient had persistent thrombocytopenia ( /l self supporting) until his death at 7 months. Toxicity Oropharyngeal mucositis and hemorrhagic cystitis were the most frequent toxicities and were graded as severe ( WHO grade 3) in respectively, 63 and 16 of patients. No patient had a confirmed diagnosis of VOD according to Jones criteria. 14 Liver toxicity, as defined according to previously mentioned criteria, was recorded in five patients who had an increase in bilirubin level of at least twice their basal value at a median of 5 days after BMT. In four of these patients (21) weight gain exceeding 5 of basal value was also observed at a median of 6 days (range 5 7). GVHD Of the 18 patients who engrafted and could be evaluated for acute GVHD, six (33) had grade II to IV disease. All three patients with grade IV GVHD died due to this complication. Chronic GVHD was assessed in 13 patients who survived days after BMT and was absent in 11 of them, moderate in one and extensive in one patient. Response to BMT Four patients who died between days 38 and 47 after BMT were considered not assessable for response. Among the remaining 15 evaluable patients, there were eight complete responders, five partial responders and two non responders. Overall, the CR rate was 42 (95 CI: 23 63) of all patients who entered the study and 53 (95 CI: 75) of those who were evaluable (Table 2). Disappearance of M protein on immunofixation analysis required a median of 6 months after transplant and was significantly related to the status of the disease at conditioning. In particular, patients with chemosensitive disease had an overall CR rate of 86 (95 CI: 49 97) vs only 17 (95 CI: 1 45) for those in whom BMT was performed as salvage therapy for advanced refractory or progressive MM (P =.6) (Table 2). Relapse-progression rate Eight patients out of 15 (53; 95 CI: 75) who were assessable for tumor response showed signs of relapse or progression after transplant. The relapse or progression rate was 33 (95 CI: 1 ) for patients with chemosensitive disease and 67 (95 CI: 35 88) for those with refractory or progressive MM (Table 2). Within this latter subgroup, six patients relapsed (n = 2) or progressed (n = 4) after 4 to 27 months (median 14.5) and died of MM at a median of 23.5 months (range 15 47) from BMT. Two patients out of six who responded to conventional chemotherapy relapsed after transplant, one at 12 months and the other at 14 months. The latter patient died due to MM at 34 months while the former is currently alive, with persistent and stable disease, at 57 months. The remaining four patients are currently alive in continuous CR after 54, 66, and 94 months, respectively. Survival At the censoring date of June 1997, the longest followup extended to 94 months from BMT and the median follow-up was 21 months for all patients and 66 months for survivors. Fourteen patients died, seven due to progressive MM and seven (37) of transplant-related complications. Six of these latter patients died by day for the following causes: acute GVHD (three patients); CMV pneumonia (one patient); infection (one patient); graft failure (one patient). One additional patient died due to extensive chronic GVHD at 7 months after BMT. Figure 1a shows the actuarial survival curve of the whole series of patients: the median was 21 months and the 4-year probability of survival was 26 (95 CI: 7 46). Analysis of several preconditioning variables potentially affecting the outcome of BMT revealed that prior responsiveness to conventional 29 Table 2 Rates of complete remission and relapse/progression according to disease status before transplant No. () of patients with Complete remission Relapse/Progression Out of total Out of evaluable Out of evaluable All patients 8/19 (42) 8/15 (53) 8/15 (53) Chemosensitive 6/7 (86) 6/6 () 2/6 (33) Refractory/Progressive 2/12 (17) 2/9 (22) 6/9 (67) P.6.6.2

4 a a 5 All patients 5 2 All patients 2 1 b 1 b Chemosensitive Chemosensitive Refractory/Progressive Figure 1 Overall survival from BMT for all patients (a) and according to disease status before transplant (b). Patients with chemosensitive disease ( ) had a significantly longer survival than those who failed prior chemotherapy ( ) (p =.4). 2 1 Refractory/Progressive Figure 2 Event-free survival from BMT for all patients (a) and according to disease status before transplant (b). The risk of any event (death or relapse/progression) was significantly lower among patients with chemosensitive disease ( ) than among those who failed prior chemotherapy ( ) (p =.1). chemotherapy was closely linked to reduced transplantrelated mortality rate (14) and extended survival duration (4-year projected: 71; 95 CI: 38 ) (Figure 1b). Five of these patients are currently alive after 54 to 94 months from BMT. In contrast, the median survival for patients with refractory or progressive MM was less than 1 year and none of them survived for more than 4 years after transplant (Figure 1b). Among post-engraftment factors, attainment of CR was a favorable prognostic variable, with a probability of survival at 4 years from BMT of 62 (95 CI: 29 96) (P =.1). Event-free survival The median time from BMT until death or relapse/progression was 12 months and the 4-year projected probability of being alive free from any event was 21 (95 CI: 3 39) (Figure 2a). Fifty-seven per cent (95 CI: 2 93) of patients with chemosensitive disease were projected to be alive free from any event at more than 4 years after BMT (P =.1) (Figure 2b).

5 Discussion The present study was performed with the aims of investigating the toxicity and antineoplastic activity of BU- CY 4 as conditioning therapy for allogeneic BMT in elderly patients with MM. Experience with this preparative chemotherapy combination had been previously accumulated in younger patients with a variety of malignant and nonmalignant hematological disorders, but was limited in MM. A preliminary case report on a single patient treated with BU at 16 mg/kg and CY at the lower dose of 12 mg/kg (BU-CY 2) was first described by Copelan and Tutschka. 9 This pilot experience was subsequently extended by the Seattle group who identified the doses of BU as 14 mg/kg and of CY as 147 mg/kg as the maximum tolerable for MM patients. 1 In the present series, BU-CY 4 was generally well tolerated. No life-threatening or fatal treatment-related complications were observed. In particular, none of our patients had a confirmed diagnosis of VOD which was, in contrast, found in 2 of patients enrolled in the Seattle study. 1 An incidence of VOD as low as 4 was also documented by Reece et al 8 in a series of patients who received the BU-CY 2 protocol as conditioning or permutations of this regimen composed of the addition of high-dose melphalan to lower doses of BU (12 mg/kg) and CY ( 12 mg/kg). The use of different diagnostic criteria in various studies may partly explain the differences in the reported frequency of VOD. In the current analysis we used Jones criteria 14 which are more restrictive than those established by McDonald 22 and allow the identification of a subgroup of patients who are more likely to develop severe hepatic dysfunction associated with an unfavorable prognosis. Also, the frequency and mortality from interstitial pneumonia (IP) were lower in the current trial than in previous reports on TBI-including treatments, 5,6 mortality approaching only 5. Whether the reduced risk of IP was the result of avoiding irradiation or the routine use of prophylactic high-dose acyclovir or both of these factors is difficult to assess. Whatever the explanation, lung toxicity from BU-CY is likely to be modest, thus contributing to the reduced mortality associated with this modality of treatment. The second aim of our study was to define the antimyeloma efficacy of BU-CY 4. Using stringent criteria, which included the disappearance of M protein on immunofixation analysis, we found a CR rate of 42 among all patients. This figure is consistent with previously reported studies, with or without TBI as part of the preparative program. 5 8,1,23 25 Although differences among these trials in terms of patient populations, disease features and criteria used to define CR (ie less or more restrictive) prevent formal comparisons of TBI and non-tbi containing regimens, it is likely that the combination of BU with CY is equivalent to TBI-CY for the primary endpoint of achieving CR post-transplant. Variables associated with high CR rates have recently been identified as less advanced clinical stage at diagnosis and less extensive exposure to conventional chemotherapy. 24 In the present study, prior responsiveness to conventional chemotherapy favored a significantly higher CR rate in comparison to advanced refractory or progressive disease. These results, albeit potentially weakened by the relatively small number of patients evaluated, have recently been reproduced in a multivariate analysis performed on a larger series of patients. 26 Another important issue related to the use of allogeneic BMT for the treatment of MM is the capability of this procedure to prolong the duration of remission, thereby justifying the increased risk of early death in comparison with autografting. 27 With a median follow-up for survivors of 5 years, we observed a relapse or progression rate of 53 at 4 years after BMT. This value compares favorably with recent analyses carried out by the Seattle 25 and the EBMT group. 24 In this latter study nine patients remained in CR for more than 5 years after transplant and the longest survivor is currently alive at more than 12 years. 26 Although late relapses may eventually occur in some of these patients, their continued disease-free survival up to and beyond 8 1 years after BMT provides evidence that allografting has the potential ability to induce sustained remission, and hopefully cure, probably as the result of a graft-versus-myeloma effect. 28,29 Nonetheless, post-transplant relapse continues to be a major problem and in several studies it has been reported as the most frequent cause of failure of the procedure. 24 In accordance with prior observations, attainment of CR was closely linked to favorable outcome of transplant in the current series. Thus, durable responses and extended survival were observed only in the subgroup of patients with chemosensitive disease, whose post-transplant CR rate exceeded. Four of these patients are currently alive and in unmaintained CR after more than 4 years from BMT, with the longest duration of continuous CR at 88 months. We conclude that the combination of BU at 16 mg/kg and CY at 2 mg/kg as preparation for allogeneic transplantation for MM, exerts substantial antitumor activity, resulting in a relatively high CR rate and extended duration of remission. A more favorable outcome of allografting is likely to be seen among patients with chemosensitive disease, who still have no chance of cure with conventional chemotherapy. Phase II III clinical trials involving larger numbers of patients are required to define exactly the role of the BU-CY 4 regimen as early consolidation myeloablative therapy followed by the support of allogeneic hemopoietic progenitors in MM. Acknowledgements This work was supported in part by MURST, Project, and University of Bologna (Funds for selected research topics). References 1 Osserman EF, Dire J, Sherman WH et al. Identical twin marrow transplantation in multiple myeloma. Acta Haematol 1982; 68: Gahrton G, Ringden O, Lönqvist B et al. Bone marrow transplant in three patients with multiple myeloma. Acta Med Scand 1986; 219: Tura S, Cavo M, Baccarani M et al. Bone marrow transplantation in multiple myeloma. Scand J Haematol 1986; 36:

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