Low-dose melphalan induces favourable responses in elderly patients with high-risk myelodysplastic syndromes or secondary acute myeloid leukaemia

We treated 21 elderly patients with high-risk myelodysplasia (n = 14) or secondary acute myeloid leukaemia (n = 7) with 2 mg of melphalan orally once a day until a complete peripheral response was obtained or until there was evidence of treatment failure. We observed seven (30%) complete and two (10%) partial peripheral responses occurring within 4-16 weeks and lasting for 12 + to 55 weeks. In relapse, retreatment was successful in most of the patients. Responses were associated with the absence of complex cytogenetic abnormalities and with a normal or reduced bone marrow cellularity.

The use of reduced doses of amifostine to ameliorate nephrotoxicity of cisplatin/ifosfamide-based chemotherapy in patients with solid tumors

This study evaluates the degree of kidney damage during cisplatin/ifosfamide-based combination chemotherapy and its possible prevention by amifostine. Thirty-one patients with solid tumors stratified according to pretreatment were randomized to receive cisplatin/ifosfamide-based chemotherapy with or without amifostine (1000 mg absolute) given as a short infusion prior to cisplatin. Chemotherapy consisted of cisplatin (50 mg/m2), ifosfamide (4 g/m2) and either etoposide (500 mg/m2) (VIP regimen) or paclitaxel (175 mg/m2) (TIP regimen) repeated at 3 weekly intervals. For all patients the glomerular filtration rate (GFR) measured by creatinine clearance, serum creatinine, electrolytes and differential urinary protein excretion were determined prior to, during and after each treatment cycle. A total of 62 cycles of chemotherapy were evaluable. In the amifostine arm the GFR was almost completely maintained after application of two cycles of chemotherapy (121 to 108 ml/min), whereas in the control group a 30% reduction of the GFR (105 to 80 ml/min) was observed. In both groups marked increases of glomerular and tubular marker profiles peaking at day 3 after chemotherapy were found with a nearly complete reversibility of these changes prior to the next chemotherapy cycle. Patients receiving amifostine had a lower degree of hypomagnesemia, as well as a lower urinary excretion of N-acetyl-glucosaminidase and albumin, indicating less tubular damage compared to the control patients. Treatment with 1000 mg amifostine resulted in an almost complete preservation of GFR. This corresponded to a slightly reduced excretion of tubular marker proteins and a lower incidence of hypomagnesemia during chemotherapy in amifostine patients compared to controls. This dose of amifostine may be sufficient for nephroprotection in patients without pre-existing risk factors for renal damage who undergo a restricted number of chemotherapy cycles.

Ex vivo manipulation of hematopoietic stem and progenitor cells

Ex vivo manipulations of hematopoietic stem and progenitor cells are Increasingly used in the context of autologous and allogeneic stem-cell transplantation. These manipulations include the positive selection of CD34+ cells for tumor-cell reduction and/or T-cell depletion, the ex vivo expansion of hematopoietic progenitor and stem cells under appropriate cytokine-stimulated culture conditions, and the ex vivo generation of myeloid or megakaryocytic postprogenitor cells and Immune effector cells. This article summarizes both the preclinical data on the ex vivo expansion of hematopoietic progenitor and stem cells from purified CD34+ cells and the Initial clinical studies with ex vivo-expanded stem and progenitor cells for hematopoietic support after high-dose chemotherapy.

Therapy-related malignancies following treatment of germ cell cancer

Given the young age at which testicular cancer is treated and the excellent prognosis for patients suffering from this disease, therapy-related malignancies represent a significant problem. Therapy-related solid tumors are associated mainly with the use of radiation therapy. The risk for developing a therapy-related solid tumor is approximately 2- to 3-fold increased compared with the general population. Therapy-related leukemias are associated predominantly with chemotherapy, particularly with the use of topoisomerase-II inhibitors and alkylating agents. In general, the cumulative incidence of therapy-related leukemia is low. It is approximately 0.5% and 2% at 5 years of median follow-up for patients receiving etoposide at cumulative doses < or = 2 g/m2 and > 2 g/m2, respectively. High cumulative doses of etoposide given over a short period of time appear to be less leukemogenic than a similar dose of etoposide given over a longer period of time. There might, additionally, be a synergistic effect of cisplatin and etoposide on the induction of therapy-related leukemia. For patients who receive high-dose chemotherapy with autologous stem-cell support, the risk of therapy-related myelodysplastic syndrome and leukemia appears to be substantially lower compared with that reported in non-Hodgkin's lymphoma patients undergoing high-dose chemotherapy. The transplantation procedure itself does not appear to add to the therapy-related leukemia risk. The risk-benefit analysis in patients with testicular cancer clearly favors the use of current treatment regimens including high-dose chemotherapy. However, even the acceptably low number of therapy-related leukemias should encourage the search for equally effective but less toxic therapies.

Treatment of patients with cisplatin-refractory testicular germ-cell cancer. German Testicular Cancer Study Group (GTCSG)

With the use of cisplatin-based combination chemotherapy, metastatic testicular germ-cell tumors can be cured in 70% to 80% of patients. The combination of cisplatin, etoposide and bleomycine (PEB) is considered standard therapy. Patients refractory to cisplatin-based chemotherapy have a markedly poor prognosis. Several chemotherapeutic agents have been evaluated in intensively pre-treated or cisplatin-refractory patients. Neither the anthracyclines nor vinorelbine, topotecan or biological agents such as suramin and retinoic acid have demonstrated clinical activity. Paclitaxel has been evaluated at different doses and schedules and yielded a response rate of 21% (range 11-30%), with single patients achieving complete remissions. This has led to the inclusion of paclitaxel in salvage regimens in combination with cisplatin and/or ifosfamide. Two studies have evaluated gemcitabine in refractory germ-cell tumors and demonstrated a response rate of 17% (95% CI 7-28%) in 52 intensively pre-treated patients, two-thirds of whom had relapsed after previous high-dose chemotherapy plus autologous stem-cell transplantation. The non-hematological toxicity of weekly gemcitabine at doses of 1,000 to 1,250 mg/m2 was tolerable, and hematological side effects included thrombocytopenia in approximately 20% of patients. Ongoing studies in refractory germ-cell tumors performed by the German Testicular Cancer Study Group are evaluating bendamustine, an alkylating agent with activity in breast and small-cell lung cancer, and oxaliplatin, a platinum derivative with incomplete cross-resistance to cisplatin. Future trials combining new active agents may examine alternating treatment strategies in patients with poor-prognostic disease or as salvage treatment.

Platinum organ toxicity and possible prevention in patients with testicular cancer

Advances in the management of metastatic testicular cancer are attributed mainly to the introduction of cisplatin into combination chemotherapy. In parallel with the development of effective chemotherapy resulting in long-term survival for the majority of patients, possible adverse effects of treatment have been systematically investigated. Besides acute side effects of cisplatin, such as gastro-intestinal toxic effects and moderate myelosuppression, reduction in glomerular filtration rate occurs in 20% to 30% of patients despite prophylactic intensive hydration and forced diuresis. Such changes in glomerular function are essentially irreversible. Persistent effects on tubular renal function occur less commonly, but hypomagnesemia due to hypermagnesiuria is often seen. Neurotoxicity, mainly sensory peripheral neuropathy, is common during treatment but disappears in the majority of patients after its completion. However, persistent paresthesias are found in 20% to 60% of patients. A typical audiometric abnormality affecting up to 50% of patients is bilateral loss of hearing at 4 to 8 kHz. A correlation between the cumulative cisplatin dose applied and the frequency of neuro- and nephrotoxicity has been demonstrated in some studies. The administration schedule additionally appears to influence the extent of toxicity, whereby single-day infusion schedules are associated with pronounced neural and renal toxicity, possibly due to higher peak plasma levels of cisplatin. Other long-term abnormalities after treatment with cisplatin-based combination regimens are a weak predisposition to secondary malignancies, infertility and chronic vascular toxicity. Several strategies have been developed to reduce such side effects. Ongoing trials are investigating the role of the aminothiol amifostine as a nephro- and neuroprotectant.

Human signal-regulatory protein is expressed on normal, but not on subsets of leukemic myeloid cells and mediates cellular adhesion involving its counterreceptor CD47

Signal-regulatory proteins (SIRPs) comprise a novel transmembrane glycoprotein family involved in the negative regulation of receptor tyrosine kinase-coupled signaling pathways. To analyze the expression and function of SIRPs, we prepared soluble recombinant fusion proteins of the extracellular regions of SIRPalpha1 and SIRPalpha2, as well as a variety of monoclonal antibodies (MoAbs) against these domains. The antibodies reacted predominantly with monocytes, granulocytes, dendritic cells, and their precursors, as well as with bone marrow CD34(+), AC133(+), CD90(+) hematopoietic stem/progenitor cells. In contrast, SIRP expression was absent or significantly reduced on the majority of myeloid blasts from patients with acute myeloid leukemia (AML) or chronic myeloid leukemia (CML). Functional studies showed that the extracellular domains of SIRPalpha1 and SIRPalpha2 support adhesion of a number of primary hematopoietic cells and cell lines. This interaction could be blocked by 4 of 7 SIRPalpha1-reactive MoAbs. In addition, SIRPalpha1 and SIRPalpha2 competed for the same cell binding site, suggesting a common widely expressed SIRP ligand. In an approach to identify this molecule, MoAbs were generated against the SIRP-binding cell line CCRF-CEM, and MoAb CC2C6 was selected because of its capacity to inhibit cell binding to SIRPalpha1. Further analysis showed that this antibody recognized CD47, a ubiquitously expressed plasma membrane protein previously implicated in integrin function, host defense action, and neutrophil migration. In this study, we identify CD47 as the extracellular ligand for human SIRP and show that these two counterreceptors are involved in cellular adhesion.

Late toxicity following curative treatment of testicular cancer

Cisplatin appears to be the major cause for long-term toxicity in patients treated for testicular cancer. Long-term side effects consist mainly of nephrotoxicity, ototoxicity, and neurotoxicity as well as gonadal damage. Following standard-dose chemotherapy approximately 20% to 30% of patients will be affected by long-term side effects, although not all these side effects will cause an impaired quality of life. Several strategies have been or currently are being evaluated to reduce acute and long-term complications including the introduction of equally effective, but less toxic regimens, or the use of cytoprotective agents such as amifostine. Secondary acute myeloid leukemia and secondary myelodysplastic syndrome probably represent the worst possible long-term complications of cancer therapy in those patients who originally were cured of their primary testicular cancer. Therapy-related solid tumors are mainly associated with the use of radiation therapy and the risk for developing a therapy-related solid tumor is increased approximately two to three times compared to the general population. In contrast, therapy-related leukemias are predominantly associated with chemotherapy, particularly with the use of topoisomerase-II inhibitors and alkylating agents. In general, the cumulative incidence of therapy-related leukemia following treatment of germ cell cancer is low. It is approximately 0.5% and 2% at 5 years of median follow-up for patients receiving etoposide at cumulative doses< or = 2 g/m(2) and >2 g/m(2), respectively. The risk-benefit analysis in patients with testicular cancer clearly favors the use of current treatment regimens including high-dose chemotherapy. However, even the acceptably low number of therapy-related long-term complications should encourage the search for equally effective but less toxic therapies. This review will highlight important available data about therapy-related toxicity and particularly, therapy-related malignancies following cisplatin-etoposide-based chemotherapy.

Successful treatment of human herpesvirus-6 encephalitis after bone marrow transplantation

We report two cases of human herpesvirus-6 (HHV-6)-associated encephalitis in patients after BMT. Both patients reported distinct neurological symptoms with disorientation, sleepiness and loss of short-term memory. Diagnosis was based on PCR analysis of the cerebrospinal fluid (CSF) positive for HHV-6 variant B-DNA. After institution of therapy with foscarnet in both cases, neurological symptoms improved and in one patient clearance of HHV-6-DNA from CSF was demonstrated. These cases show that HHV-6 infection has to be considered in patients with neurological symptoms following BMT and effective treatment of HHV-6 encephalitis is possible if instituted early.

Overexpression of the chemokine receptor CXCR4 in B cell chronic lymphocytic leukemia is associated with increased functional response to stromal cell-derived factor-1 (SDF-1)

The chemokine receptor CXCR4 and its ligand stromal cell-derived factor-1 (SDF-1) play an important role in trafficking of normal lymphocytes, monocytes, as well as hematopoietic stem- and progenitor cells. SDF-1 constitutively produced by bone marrow stromal cells acts as a chemoattractant supporting the homing of stem cells and may also contribute to the tropism of malignant cells for the bone marrow. Low-grade lymphoproliferative disorders, particularly B cell chronic lymphocytic leukemia (B-CLL), are characterized by the presence of bone marrow infiltration. Therefore, we analyzed expression of the chemokine receptor CXCR4 in B-CLL, and investigated the functional effect of SDF-1 on the malignant cells. By flow cytometry, CXCR4 was consistently expressed on circulating CLL cells at a fluorescence intensity four-fold greater than that of normal B cells, and three-fold greater than that of CD19+/CD5+ cells from the normal bone marrow. CXCR4 was functionally active as demonstrated by a rapid flux of intracellular free calcium in response to SDF-1, which was significantly reduced by the partially blocking CXCR4 antibody 12G5. Moreover, transendothelial migration of B-CLL cells in vitro was stimulated by conditioned medium from bone marrow stromal cells due to its content of SDF-1, as suggested by reduced migration after addition of the CXCR4 antibody 12G5. In accordance with the CXCR4 overexpression, migration of CLL cells was more efficiently stimulated by recombinant SDF-1 compared to migration of normal B cells. We conclude that CXCR4 is overexpressed and functionally active in B-CLL, and may therefore contribute to the tropism of B-CLL cells for the bone marrow stroma.

First-line high-dose chemotherapy compared with standard-dose PEB/VIP chemotherapy in patients with advanced germ cell tumors: A multivariate and matched-pair analysis

PURPOSE

To compare first-line high-dose chemotherapy (HD-CT) with autologous blood stem-cell transplantation to standard-dose chemotherapy (SD-CT) in male patients with advanced germ cell tumors (GCTs), a matched-pair analysis was performed within a homogenous group of patients classified as having either Indiana advanced disease or a poor prognosis according to International Germ Cell Cancer Consensus Group (IGCCCG) criteria.

PATIENTS AND METHODS

A multivariate analysis was performed that included 147 consecutive patients who had received sequential high-dose cisplatin, etoposide, and ifosfamide (VIP) therapy (HD-CT) in a German multicenter trial between 1993 and 1997 and 309 patients who had been treated with standard-dose cisplatin, etoposide, and bleomycin (PEB) or VIP chemotherapy (SD-CT) within two randomized trials at Indiana University between 1984 and 1992.

RESULTS

Multivariate analysis demonstrated HD-CT to be significantly superior to SD-CT when adjustments were made for prognostic factors (P =.021). Primary tumor site (mediastinal v retroperitoneal/gonadal, P =.035) and presence of visceral metastases (P =.0004) were shown to be significant prognostic factors for overall survival. On the basis of these factors, as well as on tumor marker levels (good, intermediate, or poor, according to IGCCCG criteria), 146 of 147 HD-CT patients were fully matched to an SD-CT patient. Median follow-up was 21 months (range, 0 to 70 months) for the HD-CT patients and 22 months (range, 0 to 90 months) for the SD-CT patients. Two-year progression-free survival (75% v 59%) and overall survival (82% v 71%) were significantly prolonged in HD-CT patients (P =.0056 and P =.0184, respectively).

CONCLUSION

The results indicate that first-line HD-CT in patients with poor-prognosis GCT may result in a significant improvement of progression-free and overall survival as compared with SD-CT. Salvage HD-CT seems not to compensate this survival advantage.

The monoclonal antibody 97A6 defines a novel surface antigen expressed on human basophils and their multipotent and unipotent progenitors

Basophils (Ba) and mast cells (MC) are important effector cells of inflammatory reactions. Both cell types derive from CD34(+) hematopoietic progenitors. However, little is known about the cell subsets that become committed to and give rise to Ba and/or MC. We have generated a monoclonal antibody (MoAb), 97A6, that specifically detects human Ba, MC (lung, skin), and their CD34(+) progenitors. Other mature hematopoietic cells (neutrophils, eosinophils, monocytes, lymphocytes, platelets) did not react with MoAb 97A6, and sorting of 97A6(+) peripheral blood (PB) and bone marrow (BM) cells resulted in an almost pure population (>98%) of Ba. Approximately 1% of CD34(+) BM and PB cells was found to be 97A6(+). Culture of sorted CD34(+)97A6(+) BM cells in semisolid medium containing phytohemagglutinin-stimulated leukocyte supernatant for 16 days (multilineage assay) resulted in the formation of pure Ba colonies (10 of 40), Ba-eosinophil colonies (7 of 40), Ba-macrophage colonies (3 of 40), and multilineage Ba-eosinophil-macrophage and/or neutrophil colonies (12 of 40). In contrast, no Ba could be cultured from CD34(+)97A6(-) cells. Liquid culture of CD34(+) PB cells in the presence of 100 ng/mL interleukin (IL)-3 (Ba progenitor assay) resulted in an increase of 97A6(+) cells, starting from 1% of day-0 cells to almost 70% (basophils) after day 7. Culture of sorted BM CD34(+)97A6(+) cells in the presence of 100 ng/mL stem cell factor (SCF) for 35 days (mast cell progenitor assay) resulted in the growth of MC (>30% on day 35). Anti-IgE-induced IgE receptor cross-linking on Ba for 15 minutes resulted in a 4-fold to 5-fold upregulation of 97A6 antigen expression. These data show that the 97A6-reactive antigen plays a role in basophil activation and is expressed on multipotent CD34(+) progenitors, MC progenitors, Ba progenitors, as well as on mature Ba and tissue MC. The lineage-specificity of MoAb 97A6 suggests that this novel marker may be a useful tool to isolate and analyze Ba/MC and their progenitors.

Future prospects in the chemotherapy of metastatic nonseminomatous testicular germ-cell cancer

The current aims of chemotherapy in metastatic testicular cancer are to reduce treatment-related toxicity in patients with "good-prognosis" metastatic disease without compromising the efficacy and to improve treatment results in "poor-prognosis" patients according to the IGCCCG classification by the use of more dose-intensive regimens. Three cycles of PEB chemotherapy, consisting of cisplatin, etoposide, and bleomycin, remain the standard treatment for good-prognosis patients despite a number of randomized studies trying to avoid the toxicity of bleomycin or to abandon cisplatin-associated side effects by substitution with the less toxic analogue carboplatin. In patients with intermediate- and poor-prognosis criteria, four cycles of PEB given at 3-weekly intervals are considered routine treatment. The role of high-dose chemotherapy with peripheral blood stem-cell (PBSC) transplantation (HDCT) is currently being investigated for patients who initially present with poor-prognosis metastatic disease and for patients with relapse after previous chemotherapy. Favorable results with long-term survival rates of approximately 75% have been achieved with up-front sequential HDCT in a phase I-II trial of the German Testicular Cancer Study Group (GTCSG) in such patients. A randomized phase III trial comparing conventional dose chemotherapy (4x PEB) with HDCT (2x PEB + 2x HD-CEC) was initiated as a United States intergroup trial in 1996. In patients with relapsed disease, conventional salvage chemotherapy results in only an approximately 20% long-term survival rate. Particularly, primary mediastinal disease and chemotherapy refractoriness represent variables associated with a very poor outcome. HDCT is also employed in relapsed patients to improve the long-term outcome. Long-term toxicity of treatment has become an important issue due to the large group of patients with metastatic disease now being cured with modern treatment strategies. The cumulative dose of cisplatin applied has been identified as a major risk factor for the development of many types of late toxicity. Despite the major advances made in the last 20 years, evaluation of the role of HDCT in both first-line and salvage treatment, investigation of new cytotoxic agents in refractory patients, and assessment of the long-term toxicities are major tasks that remain to be addressed in controlled clinical trials.

Mitomycin C continuous infusion as salvage chemotherapy in pretreated patients with advanced gastric cancer

Our purpose was to evaluate the safety and therapeutic activity of continuously infused mitomycin C in patients with recurring or progressive metastatic gastric cancer following first-line chemotherapy. Patients were treated with mitomycin C 20 mg/m2 i.v. over a time period of 120 h followed by a 3-week rest period. All patients received prednisone 50 mg p.o. prophylactically for 5 days to prevent hemolytic uremic syndrome and pulmonary side effects. Twenty-two consecutively enrolled patients were assessable for toxicity and 20 for response evaluation completing at least one full course of chemotherapy (two patients evaluable but not measurable).

PATIENT CHARACTERISTICS

median age: 63 years (39-76); Sex (M/ F): 13/9; median Karnofsky status: 70% (50-100%); resection of primary tumor n = 12 (55%); sites of metastases: liver n = 17 (77%), locally advanced n = 10 (45%), peritoneum n = 13 (59%), lungs n=5 (23%), bone n=3 (14%) and lymph nodes n=14 (64%). Previous chemotherapy regimens: bolus 5-FU/folinic acid n=6 (27%), ELF n=4 (18%), EAP n=3 (14%) and continuous 5-FU/folinic acid/cisplatin/paclitaxel n=9 (41%). In 20 evaluable patients one complete and five partial remissions were observed; overall response rate 30.0% [95% confidence interval (CI): 9.1-50.9%] with a median response duration of 2.1 months (range: 2-6). The median survival was 3.6 months (95% CI: 2.1-6.0) resulting in a 6-month survival rate of 30% since start of mitomycin C. WHO grade III/IV mucositis, diarrhea and fever/infection occurred in 9% of patients each. Cumulative thrombo- and leukocytopenia (WHO grade II/IV) were observed in four and two patients, respectively. Treatment had to be stopped early in two patients. No severe renal dysfunction, pulmonary toxicity or evidence of hemolytic uremic syndrome was observed. Fatigue during the 120 h infusion of mitomycin C was common (11 of 22 patients). We conclude that continuous infusion of mitomycin C is feasible on an outpatient basis, revealing an acceptable toxicity. Mitomycin C demonstrates single-agent activity in pretreated gastric cancer, but has only limited efficacy following cisplatin/paclitaxel-based first-line chemotherapy.

Diagnosis and treatment of patients with testicular germ cell cancer

Testicular germ cell tumours are a highly curable malignancy even in the presence of metastases, with an overall survival rate of approximately 90 to 95% when all stages are considered. Current therapeutic strategies aim at risk-adapted therapy, trying to maintain favourable overall results while reducing treatment-related toxicity, particularly in non-advanced disease. In stage I disease, unilateral inguinal orchiectomy represents the standard diagnostic and therapeutic approach. For patients with clinical stage I seminoma, prophylactic para-aortic radiotherapy with 26Gy is commonly employed. In patients with nonseminomatous germ cell tumours (NSGCT) at clinical stage I, the 3 options are: (i) retroperitoneal lymphadenectomy; (ii) a wait-and-see strategy; or (iii) 2 cycles of adjuvant chemotherapy. The individual risk profile for tumour recurrence, mainly based on histopathological criteria such as vascular tumour invasion, should guide treatment decisions in this group of patients. Radiotherapy is still the standard approach in clinical stage IIA/B seminoma, whereas in patients with a low tumour burden of NSGCT, retroperitoneal lymphadenectomy is frequently used followed by surveillance or adjuvant chemotherapy. Primary chemotherapy in these stages of disease may be at least equally successful. Major progress has also been achieved in the treatment of NSGCT patients with metastatic disease greater than clinical stage IIB, for whom primary chemotherapy represents the standard approach. After cisplatin-based combination chemotherapy, between 70 and 90% of patients will achieve a durable remission. In patients with 'good risk' metastatic disease, 3 cycles of cisplatin, etoposide and bleomycin (PEB) remain the standard treatment, despite several randomised trials trying to avoid the lung-toxic bleomycin or substituting cisplatin by carboplatin. In patients with 'intermediate' and 'poor prognosis' disease, 4 cycles of PEB given at 3-week intervals are considered routine treatment. The role of high dose chemotherapy with peripheral autologous blood stem cell transplantation is currently being investigated for patients presenting initially with advanced (poor prognosis) metastatic disease and for patients with relapse after previous chemotherapy, in whom conventional-dose salvage regimens will only result in 20% long-term survival. Because of the large group of patients with metastatic disease being cured, the possible long-term adverse effects of treatment have become important. Only a slightly elevated risk for therapy-related secondary malignancies has been identified. Long-term adverse effects associated with cisplatin may affect a larger proportion of patients. Further research should focus on reducing the risk of chemotherapy-related chronic toxicity.