High-dose chemotherapy with hematopoietic stem-cell rescue for high-risk breast cancer

Prospective, randomized comparison of high-dose chemotherapy with stem-cell support versus intermediate-dose chemotherapy after surgery and adjuvant chemotherapy in women with high-risk primary breast cancer: a report of CALGB 9082, SWOG 9114, and NCIC MA-13

PURPOSE

The prognosis for women with primary breast cancer involving multiple axillary nodes remains poor. High-dose chemotherapy with stem-cell support produced promising results in initial clinical trials conducted at single institutions.

PATIENTS AND METHODS

Seven hundred eighty-five women aged 22 to 66 years with stage IIA, IIB, or IIIA breast cancer involving 10 or more axillary lymph nodes were randomized after surgery and standard adjuvant chemotherapy to either high-dose cyclophosphamide, cisplatin, and carmustine (HD-CPB) with stem-cell support or intermediate-dose cyclophosphamide, cisplatin, and carmustine (ID-CPB) with G-CSF support but without stem cells. Planned treatment for all patients included locoregional radiation therapy. Hormone-receptor-positive patients were to receive 5 years of tamoxifen. Event-free survival (EFS) was the primary end point.

RESULTS

Median follow-up was 7.3 years. Event-free survival was not significantly different between the two treatment groups (P = .24). The probability of being free of an event at 5 years with HD-CPB was 61% (95% CI, 56% to 65%), and was 58% (95% CI, 53% to 63%) for ID-CPB. Thirty-three patients died of causes attributed to HD-CPB, compared with no therapy-related deaths among women treated with ID-CPB. Overall survival for the two arms was identical at 71% at 5 years (P = .75).

CONCLUSION

HD-CPB with stem-cell support was not superior to ID-CPB for event-free or overall survival among all randomized women with high-risk primary breast cancer.

Up-front tandem high-dose chemotherapy compared with standard chemotherapy with doxorubicin and paclitaxel in metastatic breast cancer: results of a randomized trial

PURPOSE

The role of high-dose chemotherapy (HDCT) in metastatic breast cancer remains controversial. Trials with late intensification HDCT have failed to show an advantage in overall survival. This study was initiated to compare up-front tandem HDCT and standard combination therapy in patients with metastatic breast cancer.

PATIENTS AND METHODS

Patients without prior chemotherapy for metastatic disease were randomly assigned to standard combination therapy with doxorubicin and paclitaxel (AT) or double HDCT with cyclophosphamide, mitoxantrone, and etoposide followed by peripheral-blood stem-cell transplantation. HDCT was repeated after 6 weeks. Patients were stratified by menopausal and hormone-receptor status. The primary objective was to compare complete response (CR) rates.

RESULTS

A total of 93 patients were enrolled onto the trial. Intent-to-treat CR rates for patients randomized to HDCT and AT were 12.5% and 11.1%, respectively (P = .84). Objective response rates were 66.7% for patients in the high-dose group and 64.4% for patients in the AT arm (P = .82). In an intent-to-treat analysis, there were no significant differences between the two treatments in median time to progression (HDCT, 11.1 months; AT, 10.6 months; P = .67), duration of response (HDCT, 13.9 months; AT, 14.3 months; P = .98), and overall survival (HDCT, 26.9 months; AT, 23.4 months; P = .60). HDCT was associated with significantly more myelosuppression, infection, diarrhea, stomatitis, and nausea and vomiting, whereas patients treated with AT developed more neurotoxicity.

CONCLUSION

This trial failed to show a benefit for up-front tandem HDCT compared with standard combination therapy. HDCT was associated with more acute adverse effects.

A multidisciplinary treatment strategy that includes high-dose chemotherapy for metastatic retinoblastoma without CNS involvement

The prognosis of patients with metastatic retinoblastoma is poor with conventional chemotherapy and radiation. Since retinoblastoma is highly chemosensitive, dose-escalation of chemotherapeutic agents with stem cell support should be promising. We report our experience with high-dose chemotherapy (HDC) and autologous stem cell transplantation (SCT) in patients with metastatic retinoblastoma. Five patients with metastatic retinoblastoma underwent HDC with autologous SCT following conventional chemotherapy and local radiation therapy. Stem cells (bone marrow in four and peripheral blood stem cells in one) were collected after marrow involvement was cleared. Melphalan was a key drug in all patients, and was administered in combination with other agents such as cisplatin, cyclophosphamide, carboplatin or thiotepa. Three patients are currently alive disease-free at 113, 107 and 38 months, respectively, from the time of SCT. They had no central nervous system (CNS) involvement. The two patients who died of disease had CNS involvement. No long-term sequelae of HDC have been noted. Our treatment strategy using HDC appears to be effective for treating metastatic retinoblastoma without CNS involvement.

The analysis of relapse-free survival curves: implications for evaluating intensive systemic adjuvant treatment regimens for breast cancer

Results of adjuvant dose intensification studies in patients with localised breast cancer have raised questions regarding the clinical usefulness of this treatment strategy. Here, we develop and fit a natural history model for the time to clinical tumour recurrence as a function of the number of involved lymph nodes, and derive plausible predictions of the effects of dose intensification under various conditions. The time to tumour recurrence is assumed to depend on the residual postoperative micrometastatic burden of tumour, the fractional reduction of residual tumour burden (RTB) by treatment, and the rate of regrowth of the RTB to a clinically detectable size. It is assumed that a proportion of micrometastatic tumours are unresponsive to adjuvant chemotherapy even at maximal dose intensity. Data fitted included the San Antonio Cancer Institute (SACI) database of untreated patients, and CALGB #9082, a study comparing a highly intensive and moderately intensity adjuvant regimen in patients with 10+ positive axillary nodes. The proportion of tumours unresponsive to maximally intensive adjuvant treatment is estimated to be 48% (29-67%). The estimated log kill for intermediate-dose therapy from CALGB #9082 was 6.5 logs, compared with 9 logs or greater for high-dose therapy. The model is consistent with a modest but nonnegligible advantage of dose intensification compared with standard therapies in patients with sensitive tumours who have 10+ positive axillary nodes, and suggests that much of this clinical benefit could be achieved using intermediate levels of treatment intensification. The model further suggests that, in patients with fewer than 10 involved axillary nodes, any advantage of treatment intensification over standard therapy would be much reduced, because in patients with smaller tumour burdens of sensitive tumour, a larger proportion of cures achievable with intensified therapy could be achieved as well with standard therapy.

Dose-dense adjuvant chemotherapy for primary breast cancer

Adjuvant chemotherapy has been proven to reduce significantly the risk for relapse and death in women with operable breast cancer. Nevertheless, the prognosis for patients presenting with extensive axillary lymph node involvement remains suboptimal. In an attempt to improve on the efficacy of existing chemotherapy, a phase III intergroup trial led by the Cancer and Leukemia Group B (CALGB 97-41) was designed, which tested a mathematical model of tumor growth based on the Norton-Simon hypothesis. This hypothesis, developed about 3 decades ago, and the kinetic model derived from it, created the basis of the concepts of dose density and sequential therapy, both of which were tested in CALGB 97-41. This large prospective randomized trial demonstrated that shortening the time interval between each chemotherapy cycle while maintaining the same dose size resulted in significant improvements in disease-free and overall survival in patients with node-positive breast carcinoma. This finding is highly relevant and has immediate implications for clinical practice.

Significant induction of cyclophosphamide and thiotepa metabolism by phenytoin

PATIENT AND METHOD

A 42-year-old male patient with relapsing germ-cell cancer was enrolled in a salvage protocol that employed two 4-day courses of CTC high-dose chemotherapy with cyclophosphamide (1,500 mg m(-2) day(-1)), thiotepa (120 mg m(-2) day(-1)), and carboplatin, followed by peripheral blood progenitor cell support. From five days before the start of the second CTC course the patient received phenytoin for generalized epileptic seizures. Blood samples were collected on day 1 of both CTC courses and analyzed for cyclophosphamide and its activated metabolite 4-hydroxycyclophosphamide, and for thiotepa and its main active metabolite tepa.

RESULTS

Exposure (expressed as area under the plasma concentration vs time curve) to 4-hydroxycyclophosphamide and tepa in the second CTC course was increased by 51% and 115%, respectively, compared with the first CTC course, whereas exposure to cyclophosphamide and thiotepa was significantly reduced (67% and 29%, respectively). Because high exposure to 4-hydroxycyclophosphamide and tepa correlates with increased toxicity, the treatment risk of this patient was significantly increased. Therefore doses were reduced on the third day of the second course.

CONCLUSION

It was concluded that phenytoin significantly induces both cyclophosphamide and thiotepa metabolism, most probably by induction of the cytochrome p450 enzyme system. This potential clinical significant interaction should be taken into account when phenytoin is administered in combination with cyclophosphamide and thiotepa in clinical practice.

Adjuvant chemotherapy for primary breast cancer

For patients with hormone-unresponsive or higher-risk operable early-stage breast cancer, adjuvant chemotherapy significantly reduces the risks of relapse and death. The prognosis for such patients, especially those presenting with extensive axillary lymph node involvement, remains poor. New chemotherapy agents and novel administration schedules have recently been shown to improve clinical outcome. This overview provides a summary of the state of the art and the most recent developments regarding adjuvant chemotherapy for primary breast carcinoma.

Integrated Population Pharmacokinetic Model of both cyclophosphamide and thiotepa suggesting a mutual drug-drug interaction

PURPOSE/AIMS

Cyclophosphamide (CP) and thiotepa (TT) are frequently administered simultaneously in high-dose chemotherapy regimens. The prodrug CP shows strong autoinduction resulting in increased formation of its activated metabolite 4-hydroxycyclophosphamide (4OHCP). TT inhibits this bioactivation of CP. Previously, we successfully modelled CP bioactivation and the effect of TT on the autoinduction. Recently we suggested that CP may also induce the conversion of TT in to its metabolite tepa (T). The aim of the current study was to investigate whether the influence of CP on TT metabolism can be described with a population pharmacokinetic model and whether this interaction can be incorporated in an integrated model describing both CP and TT pharmacokinetics.

METHODS

Plasma samples were collected from 49 patients receiving 86 courses of a combination of high-dose CP (4000 or 6000 mg/m2), TT (320 or 480 mg/m2) and carboplatin (1067 or 1600 mg/m2) given in short infusions during four consecutive days. For each patient, approximately 20 plasma samples were available per course. Concentrations of CP, 4OHCP, TT and T were determined using GC and HPLC. Kinetic data were processed using NONMEM.

RESULTS

The pharmacokinetics of TT and T were described with a two-compartment model. TT was eliminated through a non-inducible and an inducible pathway, the latter resulting information of T (ClindTT = 12.4 l/hr, ClnonindTT = 17.0 l/hr). Induction of TT metabolism was mediated by a hypothetical amount of enzyme, different from that involved in CP induction, whose amount increased with time in the presence of CP. The amount of enzyme followed a zero-order formation and a decrease with a first-order elimination rate constant of 0.0343 hr(-1) (t1/2 = 20 hr). This model was significantly better than a model lacking the induction by CP. The model was successfully incorporated into the previously published pharmacokinetic model for CP, and resulted in comparable parameter estimates for this compound and its metabolite 4OHCP.

CONCLUSION

The pharmacokinetics of TT, when administered in combination with CP, were successfully described. The model confirms induction of TT metabolism with time and it appears likely that CP is responsible for this phenomenon. The existence of a mutual pharmacokinetic interaction between CP and TT, as described in our integrated model, may be relevant in clinical practice.

Accuracy, Feasibility, and Clinical Impact of Prospective Bayesian Pharmacokinetically Guided Dosing of Cyclophosphamide, Thiotepa, and Carboplatin in High-Dose Chemotherapy

Purpose: Relationships between toxicity and pharmacokinetics have been shown for cyclophosphamide, thiotepa, and carboplatin (CTC) in high-dose chemotherapy. We prospectively evaluated whether variability in exposure to CTC and their activated metabolites can be decreased with pharmacokinetically guided dose administration and evaluated its clinical effect.

Experimental Design: Patients received multiple 4-day courses of cyclophosphamide (1,000–1,500 mg/m2/d), thiotepa (80–120 mg/m2/d), and carbop latin (area under the plasma concentration-time curve 3.3–5 mg × min/mL/d). Doses were adapted on day 3 based on pharmacokinetic analyses of cyclophosphamide, 4-hydroxycyclophosphamide, thiotepa, tepa, and carboplatin done on day 1 using a Bayesian algorithm. Doses were also adjusted before and during second and third courses. Observed toxicity was compared with that in patients receiving standard dose CTC (n = 43).

Results: A total of 46 patients (108 courses) were included. For cyclophosphamide, thiotepa, and carboplatin, a total of 39, 58, and 65 dose adaptations were done within courses and 17, 40, and 43 before courses. The precision within which the target exposure was reached improved compared with no adaptation, especially after within-course adaptations (precision for cyclophosphamide, thiotepa, and carboplatin is 19%, 16%, and 13%, respectively); >85% led to an exposure within ±25% of the target compared with 60% without dose adjustments. Toxicity was similar to that in a reference population, although the incidence of veno-occlusive disease was reduced.

Conclusions: Bayesian pharmacokinetically guided dosing for CTC was feasible and led to a marked reduction in variability of exposure.

Reflections on Ethical Concerns Arising from the Incorporation of Results of Randomized Trials of Antineoplastic Therapy into Routine Clinical Practice

There has been little discussion in the medical literature regarding the process whereby physicians elect to accept or reject the incorporation of results of randomized trials into their routine clinical practice. This decision-making process has the potential to result in serious ethical dilemmas.

High-dose chemotherapy with haematopoietic stem cell transplantation for metastatic breast cancer patients: final results of the French multicentric randomised CMA/PEGASE 04 protocol

The aim of our study was to evaluate the impact on time to progression (TTP) and overall survival (OS) of high-dose chemotherapy (HD-CT) over conventional CT in metastatic breast cancer patients. Between 09/92 and 12/96, 61 patients with chemosensitive metastatic breast cancer were randomised between HD-CT using the CMA regimen (Mitoxantrone, Cyclophosphamide, Melphalan) applied as consolidation (32 patients) or maintenance CT (29 patients). At randomisation, 13 patients were in complete response, 47 in partial response and one had stable disease. The median TTPs from randomisation were 6 and 12 months in the standard and intensive groups, respectively (P < 0.0056), with a relapse rate of 86.2% vs. 62.5% at 2 years, and 100% vs. 81.3% at 5 years. The median OS times were 19.3 and 44.1 months, with an OS rate of 13.8% vs. 36.8% at 5 years (P < 0.0294). The CMA regimen could prolong the TTP of patients with chemosensitive metastatic breast cancer. Further studies are needed to determine if this translates into an effect on OS.

Transplantation of hematopoietic stem cells from the peripheral blood

Hematopoietic stem cells can be collected from the peripheral blood. These hematopoietic stem cells (HSC), or better progenitor cells, are mostly expressed as the percentage of cells than react with CD34 antibodies or that form colonies in semi-solid medium (CFU-GM). Under steady-state conditions the number of HSC is much lower in peripheral blood than in bone marrow. Mobilization with chemotherapy and/or growth factors may lead to a concentration of HSC in the peripheral blood that equals or exceeds the concentration in bone marrow. Transplantation of HSC from the peripheral blood results in faster hematologic recovery than HSC from bone marrow. This decreases the risk of infection and the need for blood-product support. For autologous stem-cell transplantation (SCT), the use of peripheral blood cells has completely replaced the use of bone marrow. For allogeneic SCT, on the other hand, the situation is more complex. Since peripheral blood contains more T-lymphocytes than bone marrow, the use of HSC from the peripheral blood increases the risk of graft-versus-host disease after allogeneic SCT. For patients with goodrisk leukemia, bone marrow is still preferred, but for patients with high-risk disease, peripheral blood SCT has become the therapy of choice.

High-dose chemotherapy in breast cancer

High-dose chemotherapy is based on the scientific hypothesis that escalating the dose of drug will overcome drug resistance and improve outcome. Autologous bone marrow transplantation and, more recently, peripheral stem cell transplantation used as a means to restore marrow, made this a viable treatment for patients with selected tumours such as haematological malignancies. The role in breast cancer is less certain. Given the known as well as the potential toxicities, the objective of high-dose chemotherapy should be cure as opposed to palliation. However, the natural history of breast cancer can be protracted, with relapses occurring 15-20 years after treatment or within months of curative surgery. In breast cancer there is a positive correlation between recurrence-free and long-term survival. Therefore, the recurrence-free survival can be considered a surrogate endpoint in clinical trials. In patients with metastatic disease where cure is rare, at best, duration of a disease-free state may be a surrogate for overall benefit. Alternatively, time to progression may be another endpoint in the evaluation of treatment for metastatic disease. This is based on the assumption that quality of life is enhanced without progression of disease. Toxicity is the significant issue in the use of high-dose chemotherapy. The most common toxicity is myeloablation, potentially requiring prolonged hospitalisation. The only justification for these toxicities would be evidence of significant and meaningful benefit. A clinically relevant benefit with high-dose chemotherapy has not been seen in major randomised clinical trials of breast cancer in both the adjuvant and metastatic setting. In patients with advanced breast cancer, a small percentage may achieve long-term, disease-free survival, although there is no improvement in overall survival. Nonetheless, some investigators believe that high-dose chemotherapy holds promise, although currently this treatment is not recommended outside of a well designed prospective trial. These studies have provided useful information regarding cancer treatment. However, ongoing study of drug administration intervals, that is, dose-dense therapies, may lead to an approach that allows superior and less toxic treatment for breast cancer.

Long-term analysis and prospective validation of a prognostic model for patients with high-risk primary breast cancer receiving high-dose chemotherapy

PURPOSE

We described previously a prognostic model for high-risk primary breast cancer patients receiving high-dose chemotherapy (HDC). Such model included nodal ratio (no. involved nodes:no. dissected nodes), tumor size, hormone receptors, and HER2. In the present study we intended to test this model prospectively in a second patient cohort. In addition, we analyzed the long-term overall outcome of our HDC trials.

EXPERIMENTAL DESIGN

We analyzed all 264 patients enrolled since 1990 in our prospective trials for 4-9+, > or = 10+ nodes, or inflammatory disease. Patients of the second cohort (treated since 1997) had their prognostic score estimated prospectively before receiving HDC.

RESULTS

Fourteen patients (5.3%) died from HDC-related complications. At median follow-up of 7.1 years, relapse-free survival and overall survival of the whole group were 69.8% and 73%, respectively. Median time to relapse was 14 months (63.5% relapses within the first 2 years, 6.7% after year 5). The model was validated in the second cohort, establishing the following pretransplant risk categories: low risk (low score, HER2-), 44% patients, 87% freedom from relapse (FFR); intermediate risk (low score, HER2+), 29% patients, 68% FFR; and high risk (high score, any HER2), 27% patients, 49% FFR.

CONCLUSIONS

Few relapses are seen after year 5 of follow-up, which indicates the need for mature results of the randomized trials before their final interpretation or meta-analysis. Our prospectively validated prognostic model, if additionally confirmed in the randomized trial populations, may provide an insight into the relative benefit of HDC in different risk patient subsets.

Haematopoietic stem cell transplantation (HSCT) in Europe 2002. Changes in indication and impact of team density. A report of the EBMT activity survey

This 2002 European Group for Blood and Marrow Transplantation (EBMT) activity survey concentrates on current status, increase and decrease in haematopoietic stem cell transplantation (HSCT) activity in Europe and investigates the association of transplant rates with team density. In 2002, there were 20 207 HSCT, 6915 allogeneic (34%), 13 292 autologous (66%) and 3947 additional re- or multiple transplants collected from 586 centres in 39 European countries. Main indications were leukaemias (6523 (32%; 76% allogeneic)); lymphomas (10 760 (53%; 92% autologous)); solid tumours (1913 (9%; 92% autologous)) and nonmalignant disorders (874 (4%; 92% allogeneic)). Compared to 2001, there were increases (>10%) for AML, ALL 1st CR, CML not 1st cP, MDS, SAA and CLL in allogeneic HSCT and for MDS, Ewing's sarcoma, soft-tissue sarcoma and ovarian cancer in autologous HSCT. Decreases (>10%) were observed in autologous HSCT for acute leukaemias beyond 1st CR, CML cP, glioma, breast cancer and lung cancer. Correlation of transplant rates (number of transplants per 10 million inhabitants) with team density (number of transplant teams per 10 million inhabitants) suggests different diffusion patterns for autologous compared to allogeneic HSCT. These data describe current practice for blood and marrow transplantation in Europe and give some hints about mechanisms involved in HSCT rates.

Micrometastatic bone marrow cells at diagnosis have no impact on survival of primary breast cancer patients with extensive axillary lymph node involvement treated with stem cell-supported high-dose chemotherapy

BACKGROUND

To determine the impact of micrometastatic bone marrow cells (MMC) on survival in high-risk primary breast cancer (HRPBC) patients treated with high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT).

PATIENTS AND METHODS

Ninety-one HRPBC patients (73 patients with > or =10 involved axillary lymph nodes (ALN), 18 premenopausal women with > or =4 involved ALN) received one cycle (eight patients) or two cycles of HDCT and ASCT. Bone marrow aspiration was performed before systemic treatment to search for MMC using a cocktail of four monoclonal epithelial-specific antibodies (5D3, HEA125, BM7 and BM8). The influence of MMC and other prognostic factors on disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS) was analysed.

RESULTS

In 23 of 91 patients (25%) we detected a median of three MMC (range, 1-43) among 10(6) mononuclear cells. With a median follow-up of 62 months (range, 10-117), the detection of MMC was not associated with DFS (P=0.929), DDFS (P=0.664) or OS (P=0.642). In multivariate analysis the strongest predictor was nodal ratio for DFS (P=0.012) and expression of p53 for OS (P <0.001).

CONCLUSION

The detection of MMC at diagnosis has no impact on survival in HRPBC patients treated with HDCT and ASCT.

Phase II feasibility and pharmacokinetic study of concurrent administration of trastuzumab and high-dose chemotherapy in advanced HER2+ breast cancer

PURPOSE

To evaluate the safety of concurrent treatment with trastuzumab and high-dose chemotherapy (HDC), using cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), with autologous hematopoietic progenitor cells support, in patients with HER2+ advanced breast cancer.

EXPERIMENTAL DESIGN

Patients with HER2-overexpressing high-risk primary breast cancer (HRPBC; defined as > or =4 involved nodes or inflammatory disease), or metastatic breast cancer (MBC) were eligible. Treatment consisted of a loading dose of trastuzumab at 4 mg/kg (day -5), HDC (days -5 to -2), autologous hematopoietic progenitor cells infusion on day 0, and weekly maintenance trastuzumab (2 mg/kg) from day +1 (minimum of 9 doses). Cardiac monitoring included serial left ventricular ejection fraction measurements before treatment and on days +20 and +65.

RESULTS

Thirty-three patients were prospectively enrolled (13 HRPBC, 20 MBC). Toxicity seemed similar to that expected with this HDC regimen alone. Neutrophils and platelets engrafted promptly. There were no cases of grade 4 or 5 toxicity. One patient experienced symptomatic grade 3 acute cardiac failure on day -4, responsive to treatment. Trastuzumab did not alter the pharmacokinetics of HDC. Eleven of twelve MBC patients with measurable disease (nine of them refractory to previous chemotherapy) experienced an objective response (9 complete and 2 partial responses). At median follow-up of 34 (13-58) months, all HRPBC patients remain alive and free of disease; the MBC group has event-free survival and overall survival rates of 45 and 70%, respectively.

CONCLUSIONS

Incorporation of trastuzumab into HDC (cyclophosphamide, cisplatin, and BCNU) is feasible, with no apparent increased toxicity or pharmacokinetic interactions.

The use of high-dose cyclophosphamide, carmustine, and thiotepa plus autologous hematopoietic stem cell transplantation as consolidation therapy for high-risk primary breast cancer after primary surgery or neoadjuvant chemotherapy

We assessed the 5-year results of a high-dose cyclophosphamide, carmustine, and thiotepa (CBT) regimen plus autologous hematopoietic stem cell transplantation (AHST) as an adjuvant consolidation therapy for high-risk primary breast cancer patients with > or =10 positive axillary lymph nodes after primary surgery or > or =4 positive axillary lymph nodes after neoadjuvant chemotherapy and surgery. The associations of various potential prognostic factors with the relapse-free survival (RFS) rate and overall survival (OS) rate were determined. Between October 1992 and March 2000, 177 eligible patients (median age, 46 years) were given high-dose CBT followed by AHST. At a median follow-up of 63 months, the acute treatment-related mortality was 4.5%. Estimated 5-year RFS and OS rates were 62% and 68%, respectively, for all patients. For patients with > or =10 positive axillary lymph nodes after primary surgery, the 5-year RFS and OS rates were 71% and 70%, respectively, and for patients with > or =4 positive axillary lymph nodes after neoadjuvant chemotherapy, the 5-year RFS and OS rates were 53% and 66%, respectively. In 2-sided log-rank tests, earlier disease stage, a lower lymph node ratio, and a lower tumor score were associated with a prolonged RFS and OS. In a multivariate proportional hazards model, disease stage and lymph node ratio remained significant. We concluded that high-dose CBT with AHST for high-risk primary breast cancer is feasible, with comparable efficacy to other phase II studies. More than a 50% estimated 5-year survival rate was seen in all high-risk primary breast cancer patients. In accordance with results from recent randomized studies, we need to continue high-dose chemotherapy with AHST for patients with high-risk primary breast cancer in the phase III randomized setting.

Stem-cell transplantation for the treatment of advanced solid tumors

Over the past two decades, high-dose chemotherapy (HDC) with autologous stem-cell transplantation (ASCT) has been explored for a variety of solid tumors in adults, particularly breast cancer, ovarian cancer and non-seminomatous germ-cell tumors. The results of prospective phase II studies seemed superior in many cases to the outcome expected with standard-dose chemotherapy (SDC). The value of HDC for adult solid tumors remains, in most instances, a controversial issue, currently under the scrutiny of randomized phase III trial evaluation. ASCT pursuing an immune graft-versus-tumor effect has been evaluated in recent years for patients with advanced and refractory solid malignancies. This article reviews the results of the main phase II and III studies of HDC with ASCT, as well as the preliminary experience using allogeneic transplantation for solid tumors.

The happy destiny of frozen haematopoietic stem cells: from immature stem cells to mature applications

Forty years ago, van Putten described in the European Journal of Cancer (see this issue) quantitative studies on the optimal storage techniques of mouse and monkey bone marrow suspensions. Survival of the animals after irradiation following injection with stored bone marrow cell suspensions was the endpoint. He observed some species differences, but based on the data obtained considered a careful trial of the glycerol-polyvinylpyrrolide (PVP) combination for storage of marrow in man was indicated. In spite of this, dimethyl sulphoxide has become the 'standard' cryopreservant for human marrow stem cells. Over the last 40 years, there has been a tremendous increase in knowledge about haematopoietic stem cells and their use in the clinic. Haematopoietic stem cells are now known to travel between the bone marrow and peripheral blood and are the best-characterised adult stem cells. These cells are currently widely used for transplantations in the clinic and are obtained from a wide variety of sources. These include the bone marrow, peripheral blood, cord blood, autologous as well as allogeneic stem cells from related or unrelated donors. Increasingly, data has become available that adult haematopoietic stem cells can generate differentiated cells belonging to other cell types, a process called "developmental plasticity". Thus, they may contribute to non-haematopoietic tissue repair in multiple organ systems. This has created a whole new potential therapeutic armamentarium for the application of haematopoietic stem cells outside of the area of malignancies and haematopoietic disorders.

Dose Density in Adjuvant Chemotherapy for Breast Cancer

BACKGROUND

Dose-dense chemotherapy increases the dose intensity of the regimen by delivering standard-dose chemotherapy with shorter intervals between the cycles. This article discusses the rationale for dose-dense therapy and reviews the results with dose-dense adjuvant regimens in recent clinical trials in breast cancer.

METHODS

The papers for this review covered evidence of a dose-response relation in cancer chemotherapy; the rationale for dose-intense (and specifically dose-dense) therapy; and clinical experience with dose-dense regimens in adjuvant chemotherapy for breast cancer, with particular attention to outcomes and toxicity.

RESULTS

Evidence supports maintaining the dose intensity of adjuvant chemotherapy within the conventional dose range. Disease-free and overall survival with combination cyclophosphamide, methotrexate, and fluorouracil are significantly improved when patients receive within 85% of the planned dose. Moderate and high dose cyclophosphamide, doxorubicin, and fluorouracil within the standard range results in greater disease-free and overall survival than the low dose regimen. The sequential addition of paclitaxel after concurrent doxorubicin and cyclophosphamide also significantly improves survival. Disease-free and overall survival with dose-dense sequential or concurrent doxorubicin, cyclophosphamide, and paclitaxel with filgrastim (rhG-CSF; NEUPOGEN) support are significantly greater than with conventional schedules (q21d).

CONCLUSIONS

The delivered dose intensity of adjuvant chemotherapy within the standard dose range is an important predictor of the clinical outcome. Prospective trials of high-dose chemotherapy have shown no improvement over standard regimens, and toxicity was greater. Dose-dense adjuvant chemotherapy improves the clinical outcomes with doxorubicin-containing regimens. Filgrastim support enables the delivery of dose-dense chemotherapy and reduces the risk of neutropenia and its complications.

Hematopoetic stem cell transplantation for solid tumors in Europe

BACKGROUND

Hematopoetic stem cell transplants (HSCT) are discussed as treatment options for patients with solid tumors. Transplant numbers have changed substantially over the last decade, few controlled studies are available and different opinions prevail. Objective information on current practice is needed.

PATIENTS AND METHODS

Data from 27 902 HSCT for solid tumors (2% allogeneic, 98% autologous), collected by the European Group for Blood and Marrow Transplantation (EBMT) activity survey from 1991 to 2002 were used to assess trends, transplant rates and coefficient of variation of transplant rates in Europe.

RESULTS

Transplant numbers increased from 536 in 1991 to 4154 in 1997 and decreased to 1913 in 2002. Indications were neuroblastoma (2504 HSCT; 9%), glioma (662 HSCT; 2%), soft tissue sarcoma (1253 HSCT; 4%), germ cell cancer (3291 HSCT; 12%), breast cancer (13 524 HSCT; 48%), Ewing's sarcoma (1896 HSCT; 7%), lung cancer (387 HSCT; 1%), ovarian cancer (845 HSCT; 3%) and other solid tumors (3540 HSCT; 14%). Allogeneic cells were used in <20 cases up to 1997; since then allogeneic HSCT increased to 159 in 2002, mainly for renal cell carcinoma. Low coefficients of variation in transplant rates (<60%) are observed for Ewing's sarcoma (<56.5%), suggesting consensus for this indication.

CONCLUSIONS

These data give an overview on current practice of HSCT for solid tumors in Europe. They provide objective information for health-care providers and patient counselling.

Conventional adjuvant chemotherapy versus single-cycle, autograft-supported, high-dose, late-intensification chemotherapy in high-risk breast cancer patients: a randomized trial

BACKGROUND

Breast cancer patients with four or more positive axillary lymph nodes who are treated with conventional adjuvant therapy have a poor prognosis. In uncontrolled studies, high-dose chemotherapy produced much better results than conventional therapy. We compared the benefits of a single cycle of high-dose chemotherapy and the benefits of conventional chemotherapy in patients with high-risk breast cancer in a prospective, unblinded, randomized trial.

METHODS

Between February 23, 1995, and June 29, 1999, 605 patients with breast cancer who had four or more positive lymph nodes were randomly assigned to treatment (307 to high-dose therapy and 298 to conventional therapy). The conventional chemotherapy regimen was four cycles of doxorubicin (75 mg/m2) followed by eight cycles of CMF (cyclophosphamide [600 mg/m2], methotrexate [50 mg/m2], and 5-fluorouracil [600 mg/m2]), all given intravenously on day 1 of a 21-day cycle. The high-dose regimen was four cycles of doxorubicin (75 mg/m2), followed by a single cycle of intermediate-dose cyclophosphamide (4000 mg/m2) supported by filgrastim (300 microg/day) for up to 10 days followed by high-dose cyclophosphamide (6000 mg/m2) and thiotepa (800 mg/m2). Peripheral blood progenitor cells were harvested by leukapheresis after treatment with cyclophosphamide and filgrastim and then re-infused after the high-dose cycle. Log-rank tests were used to compare survival rates. All statistical analyses were two-sided.

RESULTS

At a median follow-up of 6 years, no statistically significant differences were detected between the arms in 5-year relapse-free survival (high-dose arm = 57%, 95% confidence interval [CI] = 51% to 63%; conventional-dose arm = 54%, 95% CI = 48% to 61% (P =.73) or in 5-year overall survival (high-dose arm = 62%, 95% CI = 56% to 68%; conventional-dose arm = 64%, 95% CI = 57% to 70%) (P =.38).

CONCLUSION

Autograft-supported, high-dose therapy is not superior to conventional chemotherapy in patients with breast cancer who have multiple involved lymph nodes. This conclusion should be viewed in the context of improving the success of conventional chemotherapy.

HER2 overexpression as a prognostic factor in metastatic breast cancer patients treated with high-dose chemotherapy and autologous stem cell support

We retrospectively evaluated the predictive and prognostic role of HER2 expression in 44 metastatic breast cancer (MBC) patients treated with high-dose consolidation chemotherapy (HDCT) and autologous stem cell support after induction chemotherapy (IC) with six courses of epirubicin+paclitaxel (22 patients) or gemcitabine+epirubicin+paclitaxel (22 patients). HER2 expression was evaluated by an immunohistochemical method (Herceptest, Dako). A total of 13 patients (29.5%) showed a HER2 overexpression (score 3+). After IC, nine patients were in complete response (CR), 30 in partial response (PR), and five in stable disease (SD); after HDCT, 20 (45.5%) obtained a CR, and 23 were in PR, for a conversion rate of 48.5%. Conversion rate for HER2-positive patients was 87.5 vs 37% for HER2-negative patients (P=0.018). The median progression-free (PFS) and overall survivals (OS) were 17.6 (95% CI 13.2-22.0) and 44 (95% CI 25.9-62.3) months, respectively. Patients with HER2 overexpression experienced a significantly (P=0.0042) shorter median PFS (15.3 months, 95% CI 11.1-19.5) compared to HER2-negative patients (21.3 months, 95% CI 14.3-28.4). The median OS was 27.6 months (95% CI 4.5-50.7) in HER2-positive patients and 50.3 months (95% CI 38.7-62.0) in HER2-negative patients (P=0.345). These results indicate that HER2 overexpression predicts a worse outcome for patients with MBC treated with HDCT, despite the high CR rate obtained in this subset of patients.

Improved haematopoietic recovery following transplantation with ex vivo -expanded mobilized blood cells*

Infusions of ex vivo-expanded (EXE) mobilized blood cells have been explored to enhance haematopoietic recovery following high dose chemotherapy (HDT). However, prior studies have not consistently demonstrated improvements in trilineage haematopoietic recovery. Three cohorts of three patients with breast cancer received three cycles of repetitive HDT supported by either unmanipulated (UM) and/or EXE cells. Efficacy was assessed by an internal comparison of each patient's consecutive HDT cycles, and to 106 historical UM infusions. Twenty-one cycles were supported by EXE cells and six by UM cells alone. Infusions of EXE cells resulted in fewer days with an absolute neutrophil count (ANC) <0.1 x 10(9)/l (median 2 vs. 4 d, P = 0.002) and 3 d faster ANC recovery to >0.1 x 10(9)/l (median 5 vs. 8 d, P = 0.0002). This resulted in a major reduction in the incidence of febrile neutropenia compared with UM cycles (0% vs. 83%; P = 0.008) and in 66% of historical UM cycles (P = 0.01) and a marked reduction in hospital re-admission. There were also fewer platelet transfusions required (43% vs. 100%; P = 0.009). We conclude that EXE cells enhance both neutrophil and platelet recovery and reduce febrile neutropenia, platelet transfusion and hospital re-admission.

Predicting Early Failure after Adjuvant Chemotherapy in High-Risk Breast Cancer Patients with Extensive Lymph Node Involvement

PURPOSE

There is limited knowledge of risk factors for breast cancer recurrence within 2 years. This study aimed to predict early failure and identify high-risk patients for prognostic and therapeutic purposes.

EXPERIMENTAL DESIGN

We studied 739 patients from a randomized trial who were <56 years of age and had >/=4 or more positive lymph nodes, no distant metastases, and no previous other malignancies. After complete surgical treatment, patients received conventional-dose anthracycline-based chemotherapy or a high-dose scheme of anthracycline-based plus alkylating chemotherapy. We assessed clinical and (immuno)histological parameters to predict recurrence within 2 years.

RESULTS

Early failure occurred in 19% (n = 137). Median survival after early failure was limited to 0.7 year. Estrogen and progesterone receptor negativity and visceral relapse predicted poor prognosis. Early failure was associated with young age, large tumors, high histological grade, angio-invasion, apical node metastasis, and >/=10 involved nodes. Estrogen receptor, progesterone receptor, and p27 negativity; HER2 overexpression; and p53 positivity also predicted early failure. The surgical or chemotherapy regimen and histological type did not. The same parameters except tumor size were associated with early death. Grade III, >/=10 involved nodes, and estrogen receptor negativity were independently associated with early failure and together identified a subset of patients (7%) with 3-fold increased early failure and 5-fold increased early death.

CONCLUSIONS

Early failure is associated with poor survival. The combination of three commonly determined parameters constitutes a strong predictive model for early failure and death.

Prognostic indicators and survival in patients with stage IIIB inflammatory breast carcinoma after dose-intense chemotherapy

PURPOSE

To improve treatment outcome for patients presenting with inflammatory breast cancer (IBC), we have sequentially developed and tested single and tandem dose-intense chemotherapy regimens (DICT). Tumor- and treatment-related factors were analyzed to generate a prognostic model.

PATIENTS AND METHODS

Between May 1989 and April 2002, 120 patients received conventional-dose chemotherapy, surgery, and sequentially developed single- or tandem-cycle DICT. Disease- and treatment-specific features were subjected to univariate and multivariate analysis to correlate with outcome.

RESULTS

At a median follow-up of 61 months (range, 21 to 161 months), estimated 5-year relapse-free survival (RFS) and overall survival (OS) were 44% (95% CI, 34% to 53%) and 64% (95% CI, 55% to 73%), respectively. In an age-adjusted multivariate analysis, RFS was better in patients with estrogen receptor (ER)/progesterone receptor (PR)-positive tumors (P =.002), for patients with fewer than four involved axillary nodes before DICT (P =.01), and in patients treated with radiation therapy (P =.001) and tandem DICT (P =.049). OS was improved in patients with ER/PR-positive tumors (P =.002), in those with fewer than four involved axillary nodes before DICT (P =.03), and in patients treated with radiation therapy (P =.002).

CONCLUSION

This retrospective analysis suggests that either single or tandem DICT can be administered safely and may benefit selected patients with stage IIIB IBC. Those with receptor-negative IBC and with four or more involved axillary nodes before DICT need improved neoadjuvant and postadjuvant intensification therapy. A prospective randomized trial of single versus tandem DICT would be required to confirm the potential benefit of tandem DICT in the setting of IBC.

Best use of adjuvant systemic therapies II, chemotherapy aspects: dose of chemotherapy-cytotoxicity, duration and responsiveness

The overall survival improvement by adjuvant chemotherapy is partly related to patient age, stage and chemotherapy regimens used. Too low dose dose-intensities or total doses will result in inferior outcomes. Conventional dose escalations above standard doses will not be beneficial for doxorubicin or cyclophosphamide, while an epirubicin dose of 90-100mg/m2 given every third week in polychemotherapy regimens results in overall survival gains. The issue is more complex, while retrospective analysis of adjuvant regimens have revealed inferior outcomes for patients receiving standard chemotherapy doses and regimens without toxicity. Most cytostatics demonstrate a marked inter-individual variation in different pharmacokinectic parameters, not compensated for by dosage based on body surface area. These facts have partly been the basis for the randomised Scandinavian Breast Group (SBG) studies SBG 9401 and 2000-1, respectively, using tailored dosage strategies aiming at interpatient equivalent dosage. Randomised studies using marrow supported-high dose strategies have so far not been demonstrated to result in overall survival improvements. G-CSF (granulocyte-colony stimulating factor) and dose-dense paclitaxel containing regimens have resulted in a small but significant survival gain compared with conventional three weekly regimens, challenging the present dogma of conventional three-four weekly scheduling, based on normal tissue side-effects rather than tumour biological considerations. The recent microarray based studies demonstrated marked inter-patient variability in gene expression and underline the potential for better patient selection and more tailored therapy strategies.

High-dose chemotherapy with autologous hematopoietic stem-cell support compared with standard-dose chemotherapy in breast cancer patients with 10 or more positive lymph nodes: first results of a randomized trial

PURPOSE

Investigation of high-dose chemotherapy (HD-CT) followed by autologous hematopoietic stem-cell support compared with standard-dose chemotherapy (SD-CT) as adjuvant treatment in patients with primary breast cancer and 10 or more positive axillary lymph nodes.

PATIENTS AND METHODS

Between November 1993 and September 2000, 307 patients were randomized to receive (following four cycles of epirubicin 90 mg/m(2) and cyclophosphamide 600 mg/m(2), intravenously every 21 days) either HD-CT of cyclophosphamide 1500 mg/m(2), thiotepa 150 mg/m(2), and mitoxantrone 10 mg/m(2), intravenously for 4 consecutive days followed by stem-cell support; or SD-CT in three cycles of cyclophosphamide 500 mg/m(2), methotrexate 40 mg/m(2), and fluorouracil 600 mg/m(2) intravenously on days 1 and 8, every 28 days. The primary end point was event-free survival.

RESULTS

After a median follow-up of 3.8 years, 144 events with respect to event-free survival have been observed (HD-CT: 63 events; SD-CT: 81 events). The first event of failure (HD-CT v SD-CT) was an isolated locoregional recurrence (nine v 11), a distant failure (52 v 68), and death without recurrence (two v two). The estimated relative risk of HD-CT versus SD-CT was 0.75 (95% CI, 0.54 to 1.06; P =.095). Overall survival showed no difference (HD-CT: 40 deaths; SD-CT: 49 deaths).

CONCLUSION

There was a trend in favor of HD-CT with respect to event-free survival, but without statistical significance. Further follow-up and a meta-analysis of all randomized studies will reveal the effect of HD-CT as compared with SD-CT as adjuvant treatment in high-risk primary breast cancer.

The curability of breast cancer and the treatment of advanced disease

Breast cancer represents a major health problem, with more than 1,000,000 new cases and 370,000 deaths yearly worldwide. In the last decade, in spite of an increasing incidence, breast cancer mortality has been declining in the majority of developed countries. This is the combined result of better education, widespread screening programmes and more efficacious adjuvant treatments. Better knowledge of breast cancer biology now allows the cosmetic, physical and psychological consequences of radical mastectomy to be spared in the majority of breast cancer patients. Use of the sentinel node technique is rapidly expanding and this will further reduce the extent and the consequences of surgery. Several clinico-pathological factors are used to discriminate between patients at low (<10%), average (10-40%) and high risk of relapse. Nodal status, tumour size, tumour grade and age are accepted universally as important factors to define risk categories. Newer factors such as uPA/PAI-1, HERer2-neu, proliferative indices and gene expression profile are promising and will allow better discrimination between patients at different risk. Endocrine manipulation with tamoxifen, ovarian ablation or both is the preferred option in the case of endocrine-responsive tumours. Tamoxifen administered for 5 years is the standard treatment for postmenopausal patients; tamoxifen plus ovarian ablation is more effective than tamoxifen alone for premenopausal women. Recent data demonstrate that, for postmenopausal patients, the aromatase inhibitors are superior to tamoxifen, with a different safety profile. At present, anastrozole can be used in the adjuvant setting in cases of tamoxifen intolerance or toxicity. Chemotherapy is the treatment of choice for steroid receptor-negative tumours. Polychemotherapy is superior to single agents and anthracycline-containing regimens are superior to CMF. Six courses of FEC or FAC or the sequential administration of four doses of anthracycline followed by four of CMF are the recommended regimens. New regimens including the taxanes have produced a further improvement in risk reduction and are reasonable therapeutic options. The taxanes have been approved for adjuvant therapy in the USA, while European approval is pending. Combined endocrine-chemotherapy is the standard adjuvant treatment in high-risk patients with endocrine-responsive tumours. Endocrine manipulation is usually administered after completion of the chemotherapy programme. For HER2-neu overexpressing tumours, several rapidly accruing trials are exploring the potential additive effect of trastuzumab, a monoclonal antibody directed against the extramembrane portion of the HER2 receptor. Primary chemotherapy is increasingly used in the treatment of locally advanced and operable breast cancer, with increased rates of breast-conserving surgery. A proportion of patients achieve a pathological complete response and these patients have significantly better long-term outcomes. Twenty-five to forty percent of breast cancer patients develop distant metastases. At this stage the disease is incurable; however, treatments can assure a significant prolongation of survival, symptomatic control and maintenance of quality of life. In the case of hormone receptor positivity and in the absence of visceral, life-threatening disease, endocrine manipulation is the treatment of choice. Active treatments include tamoxifen, ovarian ablation, aromatase inhibitors, pure anti-oestrogens and progestins. Aromatase inhibitors are the most active agents, but the choice and the sequence of endocrine therapies are also dictated by prior adjuvant treatment. Chemotherapy has to be preferred in cases of receptor-negative tumours, acquired resistance to hormones and aggressive visceral disease. Combination regimens are usually associated with higher response rates and sometimes survival prolongation, and this approach should be recommended in young patients with good performance status and visceral disease. On the other hand, single agents have a better tolerability profile and should be tand should be the treatment of choice when a careful balance between activity and tolerability is needed. For HER2-neu positive tumours, the combination of trastuzumab and chemotherapy is significantly superior to chemotherapy alone in terms of both response rates and survival. Other useful palliative treatments include bisphosphonates for the control of metastatic bone disease and radiotherapy for painful bone lesions or local relapses.

Haematopoietic stem cell transplantation: indications, clinical developments and future directions

Haematopoietic stem cell transplantation (HSCT) is an established curative treatment for many malignant and non-malignant diseases. Over the last two decades, novel approaches have resulted in significant reductions in the morbidity and mortality associated with HSCT. These include the utilisation of reduced intensity regimens, more effective graft versus host disease prophylaxis, exploration of new sources of progenitor haematopoietic stem cells and better prophylaxis and treatment of infections. Despite current advances, new strategies are needed to further reduce the complications associated with HSCT. This article reviews the current indications for HSCT and the recent progress in the field of both allogeneic- and autologous HSCT.

High-dose chemotherapy for breast cancer: is another look warranted?

PURPOSE OF REVIEW

Controversy has surrounded the use of high-dose chemotherapy for breast cancer for more than a decade. Numerous randomized trials have compared high-dose chemotherapy with standard-dose chemotherapy in metastatic breast cancer and high-risk primary breast cancer, defined by extensive axillary node involvement or inflammatory disease. The authors review the main research results of high-dose chemotherapy for breast cancer in 2002 to 2003.

RECENT FINDINGS

Preliminary analyses of three randomized trials in metastatic breast cancer and seven in high-risk primary breast cancer have been reported during this period. An advantage in event-free survival has been observed in all three studies in metastatic disease and in four of the high-risk primary cancer trials, albeit with no impact on overall survival at short follow-up. These early results are consistent with the most recent Cochrane reviews, which included trials reported through mid 2002.

SUMMARY

An early event-free survival advantage is apparent in favor of high-dose chemotherapy in both high-risk primary and metastatic breast cancer. Longer follow-up of those and most other trials is required to detect translation of the event-free survival differences into benefits in overall survival. High-dose chemotherapy remains a valid research strategy in event-free survival and high-risk primary breast cancer.

Conventional adjuvant chemotherapy with or without high-dose chemotherapy and autologous stem-cell transplantation in high-risk breast cancer

BACKGROUND

The prognosis for women with primary breast cancer and 10 or more involved axillary lymph nodes is poor. High-dose chemotherapy with autologous hematopoietic stem-cell transplantation has been reported to be effective in the adjuvant setting for patients at high risk for relapse.

METHODS

We randomly assigned 540 female patients with primary breast cancer and at least 10 involved ipsilateral axillary lymph nodes to receive either six cycles of adjuvant chemotherapy with cyclophosphamide, doxorubicin, and fluorouracil (CAF) or the same adjuvant chemotherapy followed by high-dose chemotherapy with cyclophosphamide and thiotepa and autologous hematopoietic stem-cell transplantation.

RESULTS

Among the 511 eligible patients, there was no significant difference in disease-free survival, overall survival, or the time to recurrence between those who received CAF alone and those who received CAF plus high-dose chemotherapy and stem-cell transplantation. Among 417 patients fulfilling strict eligibility criteria, the time to recurrence was longer for patients who underwent stem-cell transplantation than for those who received CAF alone. In the transplantation group, nine patients died of transplantation-related complications and a myelodysplastic syndrome or acute myeloid leukemia developed in nine.

CONCLUSIONS

The addition of high-dose chemotherapy and autologous hematopoietic stem-cell transplantation to six cycles of adjuvant chemotherapy with CAF may reduce the risk of relapse but does not improve the outcome among patients with primary breast cancer and at least 10 involved axillary lymph nodes. Conventional-dose adjuvant chemotherapy remains the standard of care for such patients.