Recurrence of Hodgkin's disease after indium-111 and yttrium-90 labeled antiferritin administration

BACKGROUND

Indium-111 labeled antiferritin targets 95% of all Hodgkin's disease lesions with a diameter of 1 cm or more. Subsequent treatment with yttrium-90 labeled antiferritin secures a high response rate in patients with recurrent Hodgkin's disease.

METHODS

A total of 87 patients were entered on one of three different yttrium-90 labeled antiferritin protocols. Recurrences after yttrium-90 treatment were analyzed. Nine patients were retreated with involved external beam radiation fields, selected with the help of indium-111 labeled antiferritin.

RESULTS

In single-agent yttrium-90 antiferritin studies, a response rate of more than 60% was found, with an average response duration of 6 months. One-third of the patients had recurrences in previously uninvolved areas. Repeat indium antiferritin scintigraphy allowed for the selection of new radiation fields for recurrences. In-field disease control was obtained for a median of 8 months, but new recurrences in new areas occurred. Chemotherapy or radiation therapy given immediately before antiferritin decreased tumor targeting with indium-111 labeled antiferritin.

CONCLUSIONS

Recurrences after radiolabeled antiferritin treatment are not due to radioresistant Hodgkin's disease. In contrast, Hodgkin's disease less than 1 cm in diameter is not targeted and not controlled by radiolabeled antiferritin. New multimodality regimens with a higher therapeutic ratio are needed for treatment of Hodgkin's disease with curative intent. Radiolabeled antiferritin can be incorporated in such regimens to secure better control of bulky Hodgkin's disease (>1 cm in diameter), but it should be given before chemotherapy or radiation therapy.

Survival of patients with chronic myelogenous leukaemia relapsing after bone marrow transplantation: comparison with patients receiving conventional chemotherapy

Treatment with busulphan and/or hydroxyurea rarely produces remission in patients with chronic myelogenous leukaemia (CML) in chronic phase. HLA-identical sibling transplants almost always produce remission, and only about 20% of patients relapse post-transplant. The increased anti-leukaemic efficacy of transplants results from intensive pretransplant treatment and immune-mediated anti-leukaemia effects. We studied 433 patients surviving > or = 2 years after diagnosis of CML to determine if patients who have relapsed after a transplant in chronic phase have longer survival from diagnosis than comparable subjects receiving chemotherapy. The chemotherapy cohort included 344 adults < 50 years of age treated on consecutive trials of the Italian Cooperative Study Group on CML between 1973 and 1986. The transplant cohort included 89 patients reported to the International Bone Marrow Transplant Registry who relapsed after an HLA-identical sibling bone marrow transplant carried out between 1978 and 1992. Survivals in the two groups were compared using Cox proportional hazards regression to adjust for prognostic variables. Median survival was 65 months in the chemotherapy cohort and 86 months in the transplant cohort. The 7-year probability (95% confidence interval) of survival was 34% (28-39%) in the chemotherapy cohort and 57% (43-70%) in the transplant cohort (P=0003). There was no difference in survival of patients relapsing after T-cell depleted and non-T-cell-depleted transplants. We conclude that patients who relapse after an HLA-identical sibling bone marrow transplant for CML in chronic phase have longer survival from diagnosis than comparable patients receiving chemotherapy. This effect is most likely to be the result of intensive chemotherapy and/or radiation given for pretransplant conditioning.

Effects of short-term in vivo administration of G-CSF on bone marrow prior to harvesting

The brief administration of G-CSF to previously treated solid tumor patients has a positive impact on the overall cellularity and progenitor cell content of harvested bone marrow. Fifty-seven patients, fully recovered from therapy and growth factor support, had approximately 500 mL of steady-state marrow harvested as outpatients under local anesthesia. Each patient then received 5 micrograms/kg of G-CSF every 12 hours subcutaneously for either 24 hours (21 patients), 36 hours (20 patients), or 48 hours (16 patients) just before harvesting 500 mL of activated bone marrow. Bone marrow cellularity (x 10(6)/mL) increased from a steady-state mean of 10.7 (+/- 0.9) to 25.7 (+/- 2.8) after 24 hours, 9.3 (+/- 0.7) to 29 (+/- 2.5) after 36 hours, and 9.6 (+/- 0.7) to 28.4 (+/- 2.5) after 48 hours. Although the percentage of CD34+ cells did not significantly change in stimulated marrow, the total number of CD34+ cells (x 10(6)) collected increased from 34 (+/- 6.3) to 52 (+/- 6.6) after two injections, 28 (+/- 3.6) to 65 (+/- 8.5) after three injections, and 28 (+/- 5.4) to 75 (+/- 18) after four injections of G-CSF. Further phenotyping demonstrated significant increases in CD34+HLA-DR+ cells with all three schedules relative to steady-state marrow. There were no changes in the total number of CD34+HLA-DR- cells after two and four shots; however, this population increased from 10 x 10(6) in steady-state marrow to 23 x 10(6) (p = 0.012) after three injections. Analysis of peripheral blood indicated a statistically significant increase in the circulating white count, but more interestingly, there were significant increases in the number of CD34+ cells x 10(4)/mL, suggesting the onset of mobilization. Steady-state blood contained a mean of 0.86 x 10(4)/mL CD34+ cells, which increased to 4.37 x 10(4)/mL, 7.43 x 10(4)/mL, and 8.62 x 10(4)/mL after two, three, and four injections, respectively-levels of CD34+ cells that are comparable to steady-state marrow. Reinfusion of a median of 1.6 x 10(6) activated CD34+ cells/kg resulted in the recovery of > 100/mm3 neutrophils and > 20,000 platelets by days 9 and 19, respectively, which was faster than our previous patients who received steady-state marrow, and comparable to our patients who received mobilized peripheral stem cells.

HLA-identical sibling bone marrow transplants vs chemotherapy for acute myelogenous leukemia in first remission

There is controversy whether adults with acute myelogenous leukemia (AML) in first remission are best treated with chemotherapy or an HLA-identical sibling bone marrow transplant. We studied 1097 adults, 16-50 years old, with AML in first remission. Results of transplants from HLA-identical siblings reported to the International Bone Marrow Transplant Registry (IBMTR; n = 901) were compared with results of chemotherapy in comparable persons treated by the German AML Cooperative Group (GAMLCG; n = 196). Preliminary analyses identified subject- and disease-related variables differing between the cohorts and associated with treatment outcome within each cohort. We adjusted for these variables and differences in time-to-treatment in subsequent comparisons of treatment-related mortality, relapse, survival and leukemia-free survival (LFS). Five-year probability of treatment-related mortality was greater for transplants than chemotherapy (43% (95% confidence interval, 37-49%) vs 7% (3-11%); P< 0.0001). Five-year relapse probability was less for transplants than chemotherapy (24% (20-28%) vs 63% (55-71%); P< 0.0001). Five-year probability of survival was similar with transplants and chemotherapy (48% (43-53%) vs 42% (33-51%); P = 0.24). Five-year LFS probability was higher for transplants than chemotherapy (46% (42-50%) vs 35% (28-41%); P= 0.01). These data indicate that bone marrow transplants from HLA-identical siblings result in comparable survival but greater LFS than chemotherapy in adults with AML in first remission.

Hematologic side effects of radiolabeled immunoglobulin therapy

Radiolabeled immunoglobulin therapy (RIT) is a new cancer treatment that is more selective than its predecessors. Its dose-limiting normal tissue side effect is bone marrow toxicity, and hematopoietic stem cell damage appears to be its most significant mechanism. Platelet consumption in irradiated normal liver tissues and apoptosis of circulating peripheral blood lymphocytes are other, less important, hematologic side effects. 131I and 90Y are the radioisotopes most commonly used for RIT; in addition, animal toxicology and initial clinical studies of chelate immunoglobulins radiolabeled with 111In (for diagnosis) or 90Y (for therapy) are reviewed. The bone-seeking properties of free 90Y are not considered to be a major component of the hematologic damage caused by yttrium-labeled immunoglobulins. The microenvironment of the bone marrow system is not significantly damaged by current RIT protocols. Moreover, granulocyte colony-stimulating factor (G-CSF) can open the blood-marrow barrier. Bone marrow toxicity after RIT can be corrected by bone marrow transplantation, growth factors, blood products, or fractionation of RIT. Selection of the appropriate corrective regimen depends on the severity of the bone marrow damage and will further enhance the therapeutic ratio of RIT.

Chemotherapy versus transplants for acute myelogenous leukemia in second remission

The best therapy for persons with acute myelogenous leukemia (AML) in 2nd remission is unknown. Bone marrow transplants from an HLA-identical sibling are reported to be better than chemotherapy but this is controversial. The objective of the study was to compare 3-year leukemia-free survival (LFS) in comparable subjects receiving chemotherapy or a transplant. 485 persons with AML in 2nd remission were studied. The chemotherapy cohort included 244 persons treated on trials of the British Medical Research Council, Eastern Cooperative Oncology Group and MD Anderson Hospital. The transplant cohort included 257 persons transplanted worldwide and reported to the international Bone Marrow Transplant Registry (16 were also chemotherapy subjects.) Subjects were selected for comparable age and year of treatment. Preliminary analyses identified two factors correlated with LFS: age < or = or > 30 years and 1st remission duration < or = or > 1 year; subsequent analyses were partitioned accordingly. Three-year probabilities of treatment-related mortality with chemotherapy and transplants were 7% (95% confidence interval, 3-15%) vs 56% (49-63%). Three-year leukemia relapse probabilities were 81% (74-86%) vs 41% (33-49%). Three-year probabilities of LFS were 17% (12-23%) vs 26 (20-32%). Cohort analysis showed significantly higher LFS with transplants vs chemotherapy in persons < or = 30 years and 1st remissions > 1 year (41% (29-53%) vs 17% (7-32%); P = 0.017) and those in > 30 years with 1st remissions < or = 1 year (18% (9-29%) vs 7% (2-16%); P = 0.046). Others had comparable LFS with both treatments. These data indicate better LFS with HLA-identical sibling transplants than chemotherapy in some persons with AML in 2nd remission.

Autologous bone marrow transplantation for acute myeloid leukemia

Despite progress over the past three decades, most patients with acute myeloid leukemia (AML) treated with conventional chemotherapy alone relapse and die of recurrent leukemia. Treatments used to improve outcome include allogeneic (alloBMT) and autologous bone marrow transplantation (ABMT). Indications for transplantation and the relative merits of alloBMT and ABMT remain unclear. In this review, we evaluate evidence supporting a role of ABMT in AML and compare the results with outcomes after alloBMT. In addition, we discuss areas of controversy including the optimal timing for ABMT, the role of bone marrow purging, the place of peripheral blood stem cell collection, the high dose regimen, and post-transplant immunotherapy to reduce relapse.

A marrow harvest procedure under local anesthesia

This report details a bone marrow harvest procedure performed outside the hospital setting under local anesthesia, thereby avoiding many of the risks associated with the traditional surgical procedure. In approximately 30 minutes, 450 milliliters of marrow can be collected from eight bone punctures, containing a median of 4.18 x 10(9) cells and 33 x 10(6) progenitor cells as defined by CD34 expression. Reinfusion of a median 1.2 x 10(6) CD34+ cells/kg in 10 breast cancer and lung cancer patients after dose-intensive chemotherapy resulted in the recovery of granulocytes > 100/mm3 by day 14 and platelets > 20,000 by day 21. Without progenitor cell support, such recoveries could take 30 and 40 days, respectively. Collection of marrow using this protocol does not compromise the engraftment capability of the progenitor cells, seldom necessitates blood product support, is safer for the patient, and reduces the cost of harvesting by 75% compared to inpatient or day surgery procedures.

Impact of cytogenetic abnormalities on outcome of bone marrow transplants in acute myelogenous leukemia in first remission

This study analyzed the impact of cytogenetic abnormalities on outcome of 1516 HLA-identical sibling bone marrow transplants for acute myelogenous leukemia (AML) in first remission reported to the International Bone Marrow Transplant Registry by 188 centers. 708 patients (47%) had cytogenetic studies performed. Transplant outcome in these subjects was similar to the 808 in whom cytogenetic studies were not performed. One or more cytogenetic abnormalities were detected in 284 (40%) of subjects studied. Relapse rates were higher and leukemia-free survival lower in patients with poor prognosis abnormalities vs those with no abnormality or with good or intermediate prognosis abnormalities (relative risk of relapse 2.40, P < 0.01; relative risk of treatment failure 1.68, P < 0.03). We conclude that cytogenetic abnormalities correlated with increased relapse in patients treated with chemotherapy. HLA-identical sibling transplants are similar.

Allogeneic bone marrow transplantation for leukemia following piperazinedione and fractionated total body irradiation

Between 1980 and 1988, 126 patients with leukemia were treated with piperazinedione and fractionated total body irradiation (TBI) followed by allogeneic bone marrow transplantation from HLA matched siblings. Sixty-one patients had acute myelogenous leukemia, 46 acute lymphoblastic leukemia, and 19 chronic myelogenous leukemia. Patients with acute leukemia in first complete remission were transplanted only if perceived to have a low probability of remaining in remission with conventional therapy. The toxicity from the preparative regimen was similar to that of cyclophosphamide and TBI except that none of the patients in the study had hemorrhagic cystitis or veno-occlusive disease. After a median follow up of 114 months, 29 patients (23%) are still alive without relapse. The survival of patients with acute myelogenous or lymphoblastic leukemia transplanted in their first remission were 35% and 43%, respectively. The survival of patients transplanted in their first chronic phase of chronic myelogenous leukemia was 60%. The results of this preparative regimen are comparable to those of cyclophosphamide and TBI.

Factors predicting long-term survival for metastatic breast cancer patients treated with high-dose chemotherapy and bone marrow support

BACKGROUND

Poor prognosis of Stage IV breast cancer patients have at best a 10% 3-year survival rate with conventional chemotherapy. Dose-intensive chemotherapy improved survival rates for some of these patients.

METHODS

All patients were Stage IV estrogen receptor-negative or estrogen receptor-positive hormonal refractory and received conventional chemotherapy (induction phase) to the point of achieving maximal response; if disease was stable or the patients responded, they entered high-dose chemotherapy (intensive phase). Seventy-six percent of the patients received two high-dose treatments with cyclophosphamide (4.5-6.0 g/m2), etoposide (750-1500 mg/m2), and cisplatin (120-180 mg/m2). Patients were randomized to receive or not receive autologous marrow. To identify prognostic factors for survival, univariate statistical analysis and multivariate models were applied to patient subsets.

RESULTS

Univariate analysis identified a number of factors whose presence indicates improvement in overall survival rates. These include: (1) absence of liver relapse (P = 0.001); (2) absence of soft tissue relapse (P = 0.001); (3) a smaller number of metastatic sites at the time of detecting Stage IV disease (P = 0.026); and (4) disease-free interval greater than 1 year from initial diagnosis to Stage IV disease (P = 0.011). Multivariate models were fitted to the data, and three variables were identified as independent negative predictors for overall survival: (1) liver site (P = 0.001); (2) soft tissue site (P = 0.039); and (3) prior adjuvant chemotherapy (P = 0.028).

CONCLUSIONS

Shorter survival after high-dose chemotherapy is predicted independently by patients pretreated with adjuvant chemotherapy, by disease distributed to the liver or the soft tissue.

Peripheral blood stem cell collection after mobilization with intensive chemotherapy and growth factors

Peripheral blood has become an alternative to bone marrow as a source of stem cells for transplantation. One of the major disadvantages of peripheral blood as a source is the low concentration of stem cells. For successful engraftment, the infusion of at least 6 x 10(8) nucleated cells per kg is required, a cell number obtained by 6-8 cell pheresis sessions. This cell number contains approximately 0.1% CD34 cells equivalent to 600,000 CD34 cells. It is known that chemotherapy and hematopoietic growth factors increase the concentration and total number of progenitor cells in the peripheral blood. In breast and lung cancer patients we are using two cytoreductive regimens: cytoxan 2 g/m2 + platinol 90 mg/m2, and VP-16 600-900 mg/m2+ platinol 90 mg/m2, respectively, in conjunction with G-CSF for stem cell mobilization. At the time of hematopoietic recovery, between day 13 and 16, the absolute number of CD34+ cells increases in 75% of the patients more than 20-fold, from 5,000 to at least 100,000/ml blood, and to more than 40-fold, to 200,000/ml, in 54% of the patients. Therefore, 3.4-7.5 ml blood contains up to 750,000 CD34+ cells, the minimum number of CD34 cells/kg body weight infused when steady-state collected peripheral blood cells are used. Since we use a minimum of 3 x 10(6) CD34+ cells/kg body weight, 15,000 ml of mobilized blood are required. This amount can often be obtained by collecting 500 ml blood by phlebotomy in 2-3 separate sessions, which is an easy and cost-effective method for the patient.

High dose chemotherapy followed by autologous hematopoietic rescue in Hodgkin's disease: long-term follow-up in 128 patients

BACKGROUND

There is little long-term follow-up information after autologous transplantation for Hodgkin's disease. We evaluated the influence of various prognostic factors and examined the outcome in 128 such patients.

PATIENTS AND METHODS

Patients received high dose cyclophosphamide, carmustine, and etoposide followed by autologous hematopoietic rescue.

RESULTS

Patients have been observed between 50-130 months (median 77 months) following transplantation. Overall survival at four years is estimated as 45 percent, and failure-free survival as 25 percent. The best results were seen in patients with a good performance status, who had failed at most one prior chemotherapy regimen. Failure-free survival at four years is estimated as 53 percent for this group. Relapses more than 24 months after transplantation were seen in 11 patients. Five patients developed myelodysplastic syndromes. Three patients became pregnant after the transplant.

CONCLUSIONS

Prolonged failure-free survival may be observed following high dose chemotherapy and autologous hematopoietic rescue in patients with Hodgkin's disease. Superior results were seen in patients without extensive prior chemotherapy and in those with a good performance status. Late relapses and deaths from secondary myelodysplastic syndromes mandate prolonged follow-up after autologous transplantation for Hodgkin's disease.

Choice of pretransplant treatment and timing of transplants for chronic myelogenous leukemia in chronic phase

We analyzed the outcome of 450 HLA-identical sibling bone marrow transplants for chronic myelogenous leukemia (CML) in chronic phase performed between 1985 and 1990 and reported to the International Bone Marrow Transplant Registry (IBMTR). All patients received either hydroxyurea (n = 292) or busulfan (n = 158) to treat their CML before transplant. The median interval between diagnosis and transplant was 10 months (range, 1 to 191). Patients treated with hydroxyurea had a higher probability (95% confidence interval) of leukemia-free survival (LFS) at 3 years than those treated with busulfan (61% [51% to 70%] v 45% [36% to 55%], P < .0003). Probability of LFS was also higher in patients transplanted within 1 year of diagnosis (61% [53 to 68%] v 47% [38% to 57%], P < .001). After adjustment for patient and transplant covariables in a multivariate analysis, prior chemotherapy and duration of disease pretransplant were independently associated with LFS. These data support the use of hydroxyurea rather than busulfan and transplant within 1 year of diagnosis for patients with CML and an HLA-identical sibling.

Yttrium 90-labeled antiferritin followed by high-dose chemotherapy and autologous bone marrow transplantation for poor-prognosis Hodgkin's disease

PURPOSE

This study was undertaken to examine the feasibility of combining radiolabeled antibody therapy with high-dose chemotherapy followed by autologous bone marrow transplantation in patients with poor-prognosis Hodgkin's disease.

PATIENTS AND METHODS

Patients were entered onto this protocol if they had chemotherapy-resistant disease, bulky disease, or extensive prior therapy. Patients received yttrium-labeled antiferritin on day -13, -12, or -11, followed by high-dose cyclophosphamide, carmustine, and etoposide (CBV) on days -6 to -3, and then bone marrow infusion on day 0.

RESULTS

Twelve patients received both radiolabeled antibody and high-dose chemotherapy followed by autologous transplantation. Two additional patients started the study, but were unable to complete all therapy. Four of 12 patients experienced early transplant-related mortality. Four patients are alive more than 2 years following transplantation and three are free from disease progression at 24+, 25+, and 28+ months following transplantation. The progression-free survival rate at 1 year is estimated to be 21%. Considering the poor prognostic characteristics of these patients, toxicity on this protocol was not necessarily greater than that observed with high-dose chemotherapy alone.

CONCLUSION

This report demonstrates the feasibility of combining radiolabeled antibody therapy with high-dose chemotherapy and autologous bone marrow transplantation.

Cisplatin-CBV with autologous bone marrow transplantation for relapsed Hodgkin's disease

The use of high-dose cyclophosphamide, carmustine, and etoposide (CBV) with autologous bone marrow transplantation (ABMT) results in long-term disease-free survival of about 30% in patients with relapsed Hodgkin's disease. Laboratory and clinical data show that cisplatin is synergistic with etoposide and carmustine, with non-overlapping extramedullary toxicity. Twenty-one patients with relapsed Hodgkin's disease that had progressed after both MOPP-like and ABVD-like regimens were treated with CBV plus cisplatin (90 mg/m2) and ABMT. The CR rate was 55%; the three-year disease-free and overall survival were 29% and 38% respectively; these results are comparable to prior experience with CBV. Performance status was strongly correlated with achievement of CR, survival, and time to treatment failure. Nephrotoxicity was seen in 3 patients, and ototoxicity in 1 patient. Although cisplatin could be added to CBV with minimal additional toxicity, the results obtained in this small patient population were not better than those of the earlier regimen. A larger trial in patients not previously exposed to cisplatin may better define the role of its addition to CBV.

OMA-AML-1: a leukemic myeloid cell line with CD34+ progenitor and CD15+ spontaneously differentiating cell compartments

OMA-AML-1 was established from a patient with acute myelomonocytic (M4) leukemia at fifth relapse when blasts were greater than 85% CD34+, CD15-. Leukemic cells were established in suspension culture and independently grown as subcutaneous tumors in SCID mice. Cells growing in suspension culture underwent differentiation by phenotypic and morphologic criteria. In contrast, cells grown as subcutaneous solid tumors in SCID mice maintained progenitor cell characteristics with high-density CD34 expression and lack of morphologic differentiation. A tendency toward differentiation to CD15+, CD34- cells in vitro and self-renewal of CD34+, CD15- cells in vivo was consistently demonstrated regardless of whether cells were initially grown in vitro or in vivo. The cell line maintains both a CD34+, CD15- progentitor cell pool and a non-overlapping, CD15+, CD34- differentiating cell compartment after more than 1 year in continuous culture. Cell cycle analysis and cloning experiments were consistent with terminal differentiation occurring in the CD15+, CD34- population. The cell line shows concentration-dependent proliferative responses to interleukin (IL)-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-6, but not to granulocyte CSF (G-CSF). OMA-AML-1 appears to mimic several features of normal myeloid hematopoiesis and should prove useful for the study of normal and malignant myeloid differentiation.

Changing trends in allogeneic bone marrow transplantation for leukemia in the 1980s

OBJECTIVE

To identify changes in practice and outcome of bone marrow transplants for leukemia in the 1980s.

DESIGN

Comparison of key explanatory and outcome variables in five 2-year cohorts, from 1980 through 1981 to 1988 through 1989, using a large database of detailed clinical information.

PATIENTS

Recipients (7788) of bone marrow transplants for acute lymphoblastic, acute myelogenous, or chronic myelogenous leukemia reported to the International Bone Marrow Transplant Registry, Milwaukee, Wis, by 185 transplant teams worldwide.

RESULTS

Linear increases occurred during the periods 1980 through 1981 to 1988 through 1989 as follows with 95% confidence intervals: (1) transplants for chronic myelogenous leukemia from 14% +/- 2% to 35% +/- 2%; (2) transplants from unrelated donors from 1% +/- 1% to 7% +/- 1%; (3) preparative regimens without radiation from 3% +/- 1% to 30% +/- 2%; and (4) use of methotrexate plus cyclosporine to prevent graft-vs-host disease from 2% +/- 1% to 55% +/- 2%. Among recipients of human lymphocyte antigen-identical sibling bone marrow, the 2-year probability of treatment-related mortality decreased by 6% to 22%. The probability of relapse decreased from 46% +/- 6% to 38% +/- 6% in intermediate leukemia but did not change appreciably in early or advanced leukemia. Probabilities of leukemia-free survival improved from 51% +/- 4% to 57% +/- 3% in early leukemia, from 28% +/- 4% to 36% +/- 5% in intermediate leukemia, and from 12% +/- 4% to 18% +/- 5% in advanced leukemia. A separate analysis of a homogenous population of patients indicated that improvements in outcome in the 1980s were due to improvements in transplant practice rather than improved patient selection.

CONCLUSIONS

Modest increases in leukemia-free survival rates occurred after human lymphocyte antigen-identical sibling bone marrow transplants in the 1980s. Improvements were due primarily to reductions in treatment-related mortality with little or no change in relapse risk. More effective antileukemia strategies and continued reductions in treatment-related toxic effects are needed.

Second bone marrow transplants for relapsed leukemia

Seventeen patients who had a relapse at a median of 9 months after marrow transplant (14 allogeneic and three syngeneic) received second transplants. Eight patients were in remission when transplanted. Of the nine patients with active disease at the time of transplant, six had complete remissions, and one converted from blastic to chronic phase of chronic myelogenous leukemia. The median survival was 9 months (95% confidence interval, 4 to 17 months). Four patients died within 100 days of transplantation, and three were disease-free. Ten patients died after 100 days, all except two of disease relapse. Five patients had remissions that were greater than 12 months and longer than the remission after their first transplant (inversions). Three patients remain alive and disease-free at 37+, 55+, and 61+ months, the former two despite remissions of less than 1 year after their first transplant. Second transplants with a different cytoreductive regimen can eradicate disease resistant to prior myeloablative treatment; some patients may benefit from second transplants, even if the first transplant only achieves a short remission.

T-cell depletion of HLA-identical transplants in leukemia

We analyzed the effects of T-cell depletion on the outcome of HLA-identical sibling bone marrow transplants for leukemia by comparing 731 T-cell-depleted transplants with 2,480 non-T-cell-depleted transplants. T-cell depletion decreased acute graft-versus-host disease (GVHD) (relative risk [RR] 0.45; P less than .0001) and chronic (GVHD) (RR 0.56; P less than .0001). However, it increased graft failure (RR 9.29; P less than .0001). Leukemia relapse also was increased. In first remission acute leukemia or chronic phase chronic myelogenous leukemia, leukemia relapse was 2.75 times more likely after T-cell-depleted transplants (P less than .0001). T-cell depletion increased the risk of treatment failure (RR 1.35; P less than .0003) and decreased leukemia-free survival. We also studied controllable variables associated with outcome of T-cell-depleted transplants. The unique findings were that among recipients of T-cell-depleted transplants for early leukemia, radiation doses greater than or equal to 11 Gy (RR 0.54; P less than .01), dose rates greater than 14 cGy/min (RR 0.56; P less than .002), and additional posttransplant immune suppression with cyclosporine alone (RR 0.53; P less than .0006) or cyclosporine plus methotrexate (RR 0.36; P less than .01) were associated with fewer treatment failures. Use of monoclonal antibodies rather than physical techniques for T-cell depletion (RR 2.01; P less than .03) and fractionated radiation (RR 1.69; P less than .05) were associated with increased treatment failure and lower leukemia-free survival. These data may be useful in designing strategies to improve results of T-cell-depleted transplants.

Diffuse pulmonary alveolar hemorrhage after bone marrow transplantation: radiographic findings in 39 patients

Diffuse alveolar hemorrhage is a life-threatening complication after bone marrow transplantation. We investigated the radiographic abnormalities that occurred in 39 transplantation patients with a diagnosis of diffuse alveolar hemorrhage and correlated the findings with the patients' clinical course. The initial radiographic abnormalities after diffuse alveolar hemorrhage developed an average of 11 days after bone marrow transplantation, and the radiographic abnormalities preceded the clinical diagnosis by an average of 3 days. Twenty-seven patients initially had bilateral radiographic abnormalities; 10 initially had unilateral abnormalities (seven in the right lung, three in the left lung). Two patients had normal chest radiographs throughout their clinical course. All 37 patients with radiographic abnormalities had abnormalities involving the central portion of the lung, primarily the middle and lower lung zones. The initial radiographic pattern was interstitial in 27 and alveolar in 10. In 24 patients, radiographic abnormalities were initially judged to be mild; three were severe from the onset. Radiographic abnormalities rapidly worsened in most patients over 6 days. In 30 patients, diffuse bilateral radiographic abnormalities involving all lung zones developed. Eleven patients persisted in having only interstitial radiographic abnormalities; 26 had a confluent alveolar pattern. At the height of radiographic abnormalities, 27 cases were judged to be severe, and only one case was judged to be mild. The mortality rate in patients with diffuse alveolar hemorrhage was 77%. The radiographic abnormalities of diffuse alveolar hemorrhage are nonspecific and usually precede the clinical diagnosis. The clinical course after hemorrhage is short, often resulting in death.

Autotransplants: now and in the future

Two points were raised in the meeting summary. One was the relative consistency of autotransplant results in lymphomas and solid tumors which appear to be about 20% 3-year disease-free survival in persons with advanced disease regardless of diagnosis. Why is this and what does it mean? Perhaps this is the limit of additional cures achievable by dose escalation; further escalations may not be more effective or may trade increased anticancer efficacy for toxicity. It is also essential to be certain that this seemingly improved outcome over conventional therapy is not the result of subject-selection or time-to-treatment biases and whether these persons are cured. The second point relates 'optimal' timing of autotransplants. Certainly, better overall results are achieved by selecting the 'best' subjects. However, prognosis factors for autotransplant outcome resemble those for chemotherapy. Therefore, a potential consequence of selecting the best subjects for autotransplants is to exclude precisely those persons most likely to benefit. Needed is a balance between improving autotransplant results and rescuing the greatest number of subjects. How to achieve this balance is presently uncertain. Presently, there is much enthusiasm for autotransplants; their use is expanding very rapidly. In some cancers and disease states autotransplants likely represent the most effective current therapy. However, this is not known to be so for most autotransplants. Controlled and/or randomized trials are now needed to evaluate efficacy in other settings. Hopefully, these studies will be performed soon.

High-dose chemotherapy and unpurged autologous bone marrow transplantation for acute leukemia in second or subsequent remission

The authors administered high-dose chemotherapy with cyclophosphamide, BCNU (carmustine) and VP-16 (etoposide) plus autologous bone marrow transplantation (ABMT) to 22 adult patients with relapsed acute leukemia in second or subsequent remission. The marrow was not treated ex vivo. The long-term, disease-free survival rate was 14%. Comparison of results with other treatments can be difficult because of patient selection biases. The concept of inversion (achievement of a longer remission with salvage therapy than with prior treatments) is proposed to compare treatment results. Three patients remain in complete remission beyond 4 years, with inversions. More intensive cytoreductive regimens will be needed to improve results.

High dose cyclophosphamide, BCNU and VP-16 with autologous blood stem cell support for refractory multiple myeloma

Eleven patients with advanced multiple myeloma refractory to standard doses of alkylating agents and salvage therapy with vincristine, adriamycin and dexamethasone (VAD) were treated with high dose cyclophosphamide, BCNU and VP-16 (CBV) with autologous blood stem cell support. Seven patients had marked marrow plasmacytosis (greater than 30%) and four had extensive pelvic bone disease precluding autologous marrow harvest. Four patients responded with a median remission duration of 7 months. Recovery of granulocytes and platelets occurred promptly in 10 evaluable patients with complete hematologic recovery. Autologous blood stem cells can provide safe and effective support for high dose CBV treatment of myeloma patients with extensive marrow plasmacytosis. The short remissions call for better cytoreductive regimens with consideration for earlier use when the myeloma may be more responsive to therapy.

Purging of T-lymphocytes with magnetic affinity colloid

There is a well-documented correlation between the number of T-lymphocytes in the bone marrow graft and subsequent development of acute graft-versus-host disease after allogeneic bone marrow transplantation. The incidence of acute graft-versus-host disease may be decreased with elimination of mature T-lymphocytes from the bone marrow graft. We have developed an immunomagnetic separation procedure using an avidin-based magnetic affinity cobalt colloid. Bone marrow cells were incubated with a combination of CD2, CD3, CD4, and CD8 monoclonal antibodies. The cells were washed and then incubated with the biotinylated, affinity-purified IgG fraction of goat anti-mouse immunoglobulins followed by an avidin-based magnetic affinity colloid. The cells were then run through a high-magnetic gradient separation column utilizing an external samarium cobalt magnet. The number of residual T-lymphocytes was assessed by limiting dilution analysis of clonogenic T-lymphocytes. This procedure produces an approximately 1.7-log reduction of antibody-reactive cells with 45% recovery of hematopoietic progenitors (granulocyte-macrophage colony-forming cells, GM-CFC). This causes a reduction of T-lymphocytes in the bone marrow graft to approximately 5 x 10(5) cells/kg body weight.

Double intensification with amsacrine/high dose ara-C and high dose chemotherapy with autologous bone marrow transplantation produces durable remissions in acute myelogenous leukemia

Eighteen adult patients under 55 years of age with acute myelogenous leukemia (AML) who entered remission with induction chemotherapy (AMSA-OAP) received two remission intensification cycles. The first intensification used amsacrine and high dose ara-C (AMSA-HDAC), and the second intensification utilized high dose cyclophosphamide, BCNU and VP-16 (CBV) plus unpurged autologous bone marrow transplantation. This double intensified program features two highly active, non-cross-resistant intensification regimens. We observed a 56% long-term disease free survival rate in this group of patients followed for a minimum time of 40 months, with very tolerable toxicity and no transplantation-related deaths. The bone marrow collected after AMSA-HDAC probably contained very low numbers of leukemic cell (in vivo purge). A multivariate logistic regression model may better define the patient population that benefits from this regimen. If these promising findings are confirmed with larger, randomized studies, this treatment strategy could be used in newly diagnosed patients with AML.

Elimination of drug-resistant myeloma tumor cell lines by monoclonal anti-P-glycoprotein antibody and rabbit complement

The effectiveness of ex vivo chemotherapy with drugs, such as vincristine, etoposide, and Adriamycin (doxorubicin, Adria Labs, Columbus, OH) for elimination of residual tumor cells from human bone marrow grafts could be undermined by the presence of multidrug-resistant tumor cells in the bone marrow. Therefore, to supplement chemoseparation, we investigated whether MRK-16, a monoclonal antibody (MoAb) to the surface moiety of multidrug resistance-associated P-glycoprotein antigen, can eliminate drug-resistant tumor cells in the presence of rabbit complement (RC). Two doxorubicin (DOX)-resistant human myeloma tumor cell line, 8226/DOX40 (resistant to 4 x 10(-7) mol/L DOX) and 8226/DOX6 (6 x 10(-8) mol/L DOX) with high and low amounts of cell surface P-glycoprotein, respectively, and the drug-sensitive parent cell line 8226/S were used as tumor models in this study. Using the limiting dilution assay, we have shown that three cycles of treatment with 25 micrograms/mL of MRK-16 MoAb and a 1:4 final dilution of RC eliminated 2.90 +/- 0.10 logs of 8226/DOX40 cells and 1.94 +/- 0.18 logs of 8226/DOX6 cells. One and two cycles of treatment were less effective, eliminating 0.47 +/- 0.40 and 1.94 +/- 0.36 logs of 8226/DOX40 and 0.12 +/- 0.20 and 1.63 +/- 0.58 logs of 8226/DOX6 cells, respectively. The 8226/S cell growth was unaffected by one to three cycles of treatment. The cell kill was not impaired when the antibody plus complement treatment was carried out on a mixture of 8226/DOX40 or 8226/DOX6 cells with a ninefold excess of irradiated bone marrow mononuclear cells (MNCs). The three cycles of treatment with antibody plus complement did not adversely affect granulocyte-macrophage colony-forming unit (GM-CFU) survival in hematologically normal marrows (92.5% to 104% survival) or in myeloma patient marrows (85% to 100%). These results show that it is possible to eliminate drug-resistant myeloma tumor cell lines from the admixed human bone marrow by treatment with MRK-16 MoAb plus RC. This method could prove to be effective for elimination of other drug-resistant tumor cell lines including those of leukemia and solid tumors, and will be further useful for supplementing chemopurging, and immunopurging of bone marrow with other antitumor cell antibodies.

Marrow transplantation for acute lymphoblastic leukemia: factors affecting relapse and survival

Transplant outcome was analyzed in 690 recipients of bone marrow transplants (BMTs) for acute lymphoblastic leukemia (ALL) in first (n = 299) or second remission (n = 391). Actuarial 5-year leukemia-free survival was 42% +/- 9% (95% confidence interval) and 26% +/- 6%, respectively; relapse rates were 29% +/- 9% and 52% +/- 8%, respectively. Five-year leukemia-free survival was 56% +/- 18% in children and 39% +/- 10% in adults (P less than .02) transplanted in first remission. In first-remission adults, non-T-cell phenotype, male to female donor-recipient sex-match and graft-v-host disease (GVHD) were associated with decreased leukemia-free survival; inclusion of corticosteroids in the regimen to prevent GVHD was associated with increased leukemia-free survival. Variables associated with decreased leukemia-free survival after second-remission transplants were age greater than or equal to 16 years and relapse occurring while on therapy. Variables associated with increased probability of relapse were similar for first- and second-remission transplants and included GVHD prophylaxis without methotrexate and absence of GVHD. In first-remission transplants, leukocyte count greater than or equal to 50 x 10(9)/L at diagnosis was also associated with increased relapse; in second remission, relapse while receiving chemotherapy was also associated with increased posttransplant relapse. These data emphasize the importance of both disease- and transplant-related variables in predicting outcome after BMT. They may be used to explain differences between studies, design future trials, and identify persons most likely to benefit from BMT.

A monoclonal antibody cocktail for detection of micrometastatic tumor cells in the bone marrow of breast cancer patients

We investigated whether monoclonal antibodies (MoAbs) reactive against both acidic and basic cytokeratins alone were sufficient to detect minimal numbers of contaminating epithelial tumor cells in the bone marrow of breast cancer patients. Monoclonal anti-cytokeratin antibodies (AE1 and AE3) were used to stain 14 breast carcinomas by the avidin-biotin-peroxidase technique. Nine tumors (64.3%) showed high reactivity and five (35.7%) showed low or moderate reactivity. Nine MoAbs that proved to be unreactive to light density bone marrow cells by immunoalkaline phosphatase histochemistry were screened for reactivity to breast carcinomas having only low or moderate positivity to cytokeratin antibodies. Three of nine MoAbs showed high percentages of positivity and were selected to supplement the anti-cytokeratin antibodies for immunohistochemical detection of minimal marrow disease in breast cancer patients. A MoAb cocktail was prepared, further tested for reactivity to another five breast carcinomas, and compared with cytokeratin staining alone. The cocktail labeled 100% of carcinoma cells in all the examined specimens. To determine the sensitivity of this panel for detecting minimal numbers of contaminating tumor cells in bone marrow, in vitro mixing experiments were performed. T47D breast carcinoma cells were mixed with bone marrow mononuclear cells at ratios from one tumor cell per 10 bone marrow cells up to one tumor cell per 1 x 10(6) marrow cells, and cytospin preparations were subsequently stained with the MoAb cocktail by the immunoalkaline phosphatase method. Our approach could detect one tumor cell in 1 x 10(5) hematopoietic cells.

Risk factors for interstitial pneumonia following bone marrow transplantation for severe aplastic anaemia

Data from 547 patients with aplastic anaemia who received bone marrow transplants from HLA-identical siblings were analysed to determine factors associated with the risk of interstitial pneumonia (IPn). IPn developed in 92 patients (17%). 37% of cases were associated with cytomegalovirus infection and 22% with other organisms; in 41% of cases no organism was identified. The case fatality rate was 64%; the mortality rate due to IPn was 11%. In multivariate analysis, four factors were associated with an increased probability of interstitial pneumonia: use of methotrexate rather than cyclosporine after transplantation (relative risk, 2.8; P less than 0.0008); occurrence of moderate to severe acute graft-versus-host disease (relative risk, 2.2; P less than 0.002); inclusion of total body radiation in the pretransplant preparative regimen (relative risk 2.2, P less than 0.004); and patient age greater than 20 (relative risk 1.7, P less than 0.002). The probability of IPn ranged from 4% for patients with none of these adverse risk factors to 51% (relative risk of 13.4) for patients with all four. The incidence of IPn decreased significantly between 1978 and 1985, paralleling a decrease in the use of total body radiation pretransplant for immune suppression and methotrexate post-transplant for prophylaxis against graft-versus-host disease.

Analysis of peripheral blood granulocyte-macrophage colony growth by limiting dilution assay

Analysis of myeloid progenitor cells in the peripheral blood (peripheral blood colony-forming unit granulocyte-macrophage; PBCFU-GM) is limited by their low frequency and by the presence of inhibitory cell populations. These factors limit the study of cytokines and cellular influences on PBCFU-GM in semisolid media assays and complicate the interpretation of data. We have developed a limiting dilution assay (LDA) in liquid culture for PBCFU-GM that allows evaluation of inhibitory or accessory effects of other cell populations and estimation of progenitor cell frequency. Using this system we have examined the inhibitory effect of autologous monocytes on in vitro colony growth. After monocyte depletion by counterflow centrifugal elutriation and adherence, colony growth with recombinant human granulocyte-macrophage colony-stimulating factor was linear over a wide range of cell densities, indicating a direct proliferative effect on circulating myeloid progenitor cells. Simultaneous PBCFU-GM assays in agar demonstrated monocyte inhibition but did not afford reliable interpretation of either progenitor frequency or linear growth kinetics in a statistically verifiable fashion. LDA in liquid culture may be a useful tool to study the effects of various cytokines and cell populations on PBCFU-GM in vitro and in vivo.

Prognostic factors for response and survival after high-dose cyclophosphamide, carmustine, and etoposide with autologous bone marrow transplantation for relapsed Hodgkin's disease

Sixty-one patients with relapsed Hodgkin's disease who had failed a mechlorethamine, vincristine, procarbazine, and prednisone (MOPP)- and a doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD)-like regimen were treated with a high-dose combination chemotherapy containing cyclophosphamide, carmustine, and etoposide (CBV) and autologous bone marrow transplantation (ABMT). Fifty-nine patients were treated in relapse and two were intensified early in third remission. Following therapy, 29 patients (47%) were in complete remission (CR), 18 patients (30%) achieved a partial response (PR), and 14 patients (23%) had progressive disease (PD). Among the partial responders, six patients achieved a CR following addition of local radiation therapy to sites of residual nodal disease. For a minimum follow-up of 2 years, 23 patients (38%) are alive and free of disease. High-dose CBV therapy produced severe myelosuppression, and there were four (7%) treatment-related deaths. A multivariate analysis identified failure of more than two prior chemotherapy treatments and poor performance status as important adverse risk factors for survival. Patients who had no adverse risk factor and/or were intensified with CBV while Hodgkin's disease was still responding to conventional chemotherapy, had a CR rate of 63%, with 77% projected 3-year survival; whereas, all other patients had a CR rate of 31%, and a projected 3-year survival of only 18%. Our results demonstrated that CBV and ABMT can induce remission duration of 2 years or greater in a significant proportion of patients with relapsed Hodgkin's disease.

Detection of minimal residual disease in acute myelogenous leukemia by RNA-in situ hybridization

Several proto-oncogenes have been reported to be expressed in normal and malignant hematopoietic cells. Since these studies have been done almost exclusively by Northern and dot-blot analyses using mixed populations of cells, any conclusions concerning quantitative changes in gene expression are difficult to document. We have developed a rapid and sensitive RNA-in situ hybridization technique permitting detection of as few as 5 copies of mRNA per individual cell. Using this technique we have studied the expression levels of several oncogenes including MYC, SIS, FMS, p53, FOS and RAF in both normal hematopoietic cells and bone marrow (BM) cells obtained from acute myelogenous leukemia (AML) patients at presentation, at relapse and in complete remission (CR). Two of these oncogenes, MYC and SIS, are expressed at levels at least 2-5-fold higher in hematopoietic cells obtained from leukemia patients than in any normal hematopoietic cell examined, including cells obtained from regenerating bone marrow. The proportion of abnormal cells correlated well with the percentage of blast cells determined by morphological examination. In 7 out of 10 AML patients in morphological remission, a subpopulation of cells is detectable with abnormally high levels of MYC and/or SIS mRNA. These high levels of MYC expression are similar to those found in BM cells obtained from AML patients at presentation or relapse, but the percentage of cells with this abnormality is generally much lower. Continued follow-up of these patients has shown that 5 of them relapsed within 8 months. At this time, none of the 3 patients which were negative for MYC overexpression has relapsed.(ABSTRACT TRUNCATED AT 250 WORDS)

High dose therapy and autologous bone marrow transplant (ABMT) in acute leukemia: is purging necessary?

Multiple clinical studies have been undertaken to evaluate the role of ABMT in relapse, in second and subsequent remission (CR greater than or equal to 2), and in first remission (CR1). The value of these high dose cytoreductive programs with ABMT is not yet known. No randomized studies have been done yet indicating that ABMT is superior to conventional dose chemotherapy. Besides, the diversity of regimens and patient populations make evaluation of results extremely difficult. When these variables are taken into account, the effect of purging on the clinical results becomes unclear. Multiple methods of purging have been devised, and several clinical trials have been reported. Although the biological role of purging is still unknown, theoretical considerations will be discussed and recommendations of patient subpopulations in which purging might be effective will be given.

Piperazinedione plus total body irradiation: an alternative preparative regimen for allogeneic bone marrow transplantation in advanced phases of chronic myelogenous leukemia

Twenty-one patients with Philadelphia chromosome-positive chronic myelogenous leukemia (CML) in advanced phases were treated with piperazinedione (PIP), total body irradiation (TBI) and allogeneic bone marrow transplantation. Eleven were in blastic transformation, five were in accelerated phase, and five were in second chronic phase. The median age was 29 years (range, 13-41 years); there were 14 males. All patients but one were rendered aplastic by this regimen. Of these, 17 had hematologic engraftment, recovering granulocytes to 1.0 x 10(9)/l in a median of 28 days (range, 11-52 days). Three patients failed to engraft. Of those who engrafted, five relapsed and died of disease, one relapsed and died of a polymicrobial wound infection, nine patients died of treatment-related complications, including graft-versus-host disease, interstitial pneumonitis and sepsis, and one patient developed large-cell lymphoma 27 months after transplant and died of this 18 months later. One patient relapsed after 31 months died of polymicrobial sepsis at 37 months, and one patient remains disease-free at 54+ months. The 3-year survival rate was 14%. Survival at 1 year was related to having a spleen that did not extend beyond 2 cm below the left costal margin at the time of transplantation, and those with a large spleen at initial presentation relapsed more often. PIP-TBI with allogeneic bone marrow transplantation can induce durable remissions in a small proportion of patients in advanced phases of CML, but it is not superior to cyclophosphamide-TBI in this patient group.

Evaluation of drugs for elimination of leukemic cells from the bone marrow of patients with acute leukemia

Relatively nonmyelotoxic drugs and drug combinations were investigated for their ability to eliminate malignant cells from human bone marrow. In vitro 90% inhibitory concentration (IC90) doses were established on granulocyte macrophage colony-forming units (GM-CFU) in culture of bone marrow by using the GM-CFU assay for the following drugs: 4-hydroperoxycyclophosphamide (4-HC), Adriamycin, L-asparaginase, bleomycin, hydrocortisone, VP-16, spirogermanium, Taxol, and vincristine. The leukemic cell kill efficiency of these drugs at IC90 doses was compared with that of 4-HC on acute lymphoid leukemia (ALL) cell lines by using the limiting-dilution assay. Under these conditions, no single drug was superior to 4-HC. To increase the in vitro effect in leukemic cell kill, combinations of vincristine with hydrocortisone, Adriamycin, VP-16, and 4-HC were investigated. Vincristine at 1 to 5 micrograms/mL increased the marrow cytotoxicity of hydrocortisone, Adriamycin, and VP-16, but it was protective (subadditive) with 4-HC. Vincristine and 4-HC in combination was additive to supraadditive on ALL cell lines, increased the leukemic cell kill by one to two logs above 4-HC alone at IC90 doses (P less than .05), and was not affected by the addition of excess marrow cells. The recommended doses for chemopurging in clinical studies are vincristine, 1 to 5 micrograms/mL, plus 4-HC, 5 micrograms/mL.

The role of autologous bone marrow transplantation in acute leukemia

One hundred and twenty-seven patients with acute leukemia were treated with high-dose cytoreductive programs in conjunction with autologous marrow. Transplantation in relapse resulted in a complete remission rate ranging from 33% to 72%, depending on the time of transplantation, the conditioning regimen used and the performance status of the patient. Remission duration was short, ranging from three to nine months. Transplantation in second or subsequent remission did not change the natural history of the disease. In 14% of the cases, transplantation remissions were obtained exceeding the duration of the preceding remission, results equivalent to those obtained by normal dose chemotherapy. Transplantation in first remission (CR1) resulted in a projected two-year disease-free survival of 72% (13% SE) in acute myelogenous leukemia and of 45% (17% SE) in acute lymphocytic leukemia. We conclude from these data that the results look promising in CR1 and that in second and subsequent remissions a realistic study design is possible by which the influence on the natural history of disease by changing the bone marrow transplantation program, such as purging in vitro, can be studied.

Risk factors for acute graft-versus-host disease

Acute graft-versus-host disease (GvHD) is an important complication of bone marrow transplantation in humans. Risk factors are imprecisely defined and controversial. We analysed data from 2036 recipients of HLA-identical sibling transplants for leukaemia or aplastic anaemia to identify risk factors for GvHD. Analyses indicate that grading of GvHD can be reproducibly divided into absent or mild versus moderate to severe; 2-year actuarial probability was 54% (95% confidence interval 52-56%) for absent or mild and 46% (44-48%) for moderate to severe. Factors predictive of development of moderate to severe GvHD include donor/recipient sex-match (female----male greater than others, relative risk 2.0, P less than 0.001). This risk was markedly increased if female donors for male recipients were previously pregnant or transfused (relative risk 2.9, P less than 0.0001). Older patients were at increased risk of GvHD (relative risk 1.6, P less than 0.001), but the age gradient was modest, even the youngest patients had a substantial risk of GvHD and, if parous or transfused female----male transplants were excluded, age was not a significant risk factor. Cyclosporine or methotrexate were equally effective at preventing GvHD and were superior to no prophylaxis (relative risk 2.3, P less than 0.01). These data should be useful in estimating the risk of acute GvHD in an individual patient and in designing clinical trials to investigate methods to modify or prevent GvHD.