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Originally published as JCO Early Release 10.1200/JCO.2002.07.177 on August 29 2002 © 2002 American Society for Clinical Oncology
Use of Epoetin in Patients With Cancer: Evidence-Based Clinical Practice Guidelines of the American Society of Clinical Oncology and the American Society of HematologyByFrom the Medical College of Wisconsin, Milwaukee, WI; Cleveland Clinic Foundation, Cleveland, OH; Virginia Commonwealth University, Richmond, VA; Blue Cross and Blue Shield Association Technology Evaluation Center and Veterans Affairs Chicago Health Care System, Chicago; Evanston Northwestern Healthcare, Evanston, IL; H. Lee Moffitt Cancer Center and Research Institute at the University of South Florida, Tampa, FL; patient representative, Mesa; University of Arizona Health Sciences Center, Phoenix, AZ; Memorial Sloan-Kettering Cancer Center, New York, NY; Dana-Farber Cancer Institute, Boston, MA; Saint Agnes Hospital, Baltimore, MD; NW Kaiser Permanente and Northwest Cancer Specialists, Portland, OR; and Hamilton Regional Cancer Center, Hamilton, Ontario, Canada. Address reprint requests to American Society of Clinical Oncology, Health Services Research Department, 1900 Duke St, Suite 200, Alexandria, VA 22314; email: guidelines{at}asco.org
ABSTRACT: Anemia resulting from cancer, or its treatment, is an important clinical problem increasingly treated with the recombinant hematopoietic growth factor erythropoietin. To address uncertainties regarding indications and efficacy, the American Society of Clinical Oncology and the American Society of Hematology developed an evidence-based clinical practice guideline for the use of epoetin in patients with cancer. The guideline panel found good evidence to recommend use of epoetin as a treatment option for patients with chemotherapy-associated anemia with a hemoglobin level less than 10 g/dL. Use of epoetin for patients with less severe anemia (hemoglobin < 12 g/dL but never below 10 g/dL) should be determined by clinical circumstances. Good evidence from clinical trials supports the use of subcutaneous epoetin thrice weekly (150 U/kg tiw) for a minimum of 4 weeks. Less strong evidence supports an alternative weekly (40,000 U/wk) dosing regimen, based on common clinical practice. With either administration schedule, dose escalation should be considered for those not responding to the initial dose. In the absence of response, continuing epoetin beyond 6 to 8 weeks does not appear to be beneficial. Epoetin should be titrated once the hemoglobin concentration reaches 12 g/dL. Evidence from one randomized controlled trial supports use of epoetin for patients with anemia associated with low-risk myelodysplasia not receiving chemotherapy; however, there are no published high-quality studies to support its use for anemia in other hematologic malignancies in the absence of chemotherapy. Therefore, for anemic patients with hematologic malignancies, it is recommended that physicians initiate conventional therapy and observe hematologic response before considering use of epoetin.
A NEMIA SECONDARY to a diagnosis of cancer, or resulting from its treatment, is an important clinical problem for which new therapeutic options have recently become available. The development of chemotherapy-associated anemia is characteristically an insidious and delayed complication of treatment. Transfusion was the traditionaland onlymeans of therapy for symptomatic anemia, until the 1990s. Newer chemotherapeutic agents and drug combinations have made anemia an even more clinically significant problem. In some instances, with improved cancer therapy, treatment of malignancy has come to resemble management of chronic illness. Evolution in the management of anemia has accompanied these changes in cancer therapy. Growing concern about infectious risks has led to decreased usage of RBC transfusions. Likewise, the realization that transfusion products represent a limited resource has led to strategies to optimize their use. The identification and clinical development of the recombinant hematopoietic growth factor, erythropoietin, triggered further evolution in the management of anemia in the 1990s. Anemia caused by malignancy may be related to either (1) infiltration of marrow elements by cancer cells directly (bone marrow involvement), (2) an impaired production process directly related to treatment (the effect of cancer therapy), or (3) other nonspecific processes, such as the inhibitory effect of tumor necrosis factor that accounts for the "anemia of chronic disorders," iron deficiency, or low endogenous erythropoietin levels. The United States Food and Drug Administration approved epoetin, the human recombinant form of erythropoietin, as a pharmaceutical in 1989 for anemia of chronic renal failure. Since then, numerous studies have examined its potential usefulness as an alternative to transfusion in the management of anemia in the cancer population. Initial studies explored the use of erythropoietin in a variety of clinical oncology settings, testing various dosing and scheduling regimens. These trials typically were small in size and used a variety of regimens and schedules. Some failed to demonstrate significant benefit, perhaps because of the patient populations enrolled, the study design, or the limitations of the agent as a therapy. In addition, issues that have subsequently been recognized as critical to successful therapy, such as iron repletion, baseline hemoglobin at entry, and dosing/schedule of epoetin, were not fully appreciated. These factors were increasingly considered in subsequent, larger phase II and III trials. With greater clinical experience, trial designs have focused on fine-tuning the use of epoetin to achieve clinical outcomes such as reduced transfusion requirements and improved quality of life. Currently, the field of hematopoietic support for anemia of cancer continues to evolve. The investigation of the next generation of erythropoietin products indicates that this area will continue to change over the next several years. Nonetheless, physicians making use of current evidence confront difficult questions about the proper indications for administering epoetin in anemic patients with cancer, and confront uncertainties regarding the efficacy of this agent and the quality of the trials on which current claims of efficacy are based. Furthermore, the use of epoetin is in the context of the availability of an effective alternative form of traditional therapy, namely blood transfusion.
To address these uncertainties, the American Society of Clinical Oncology (ASCO) and the American Society of Hematology (ASH) began discussions in 1997 to develop an evidence-based clinical practice guideline on the use of epoetin in cancer patients. At that time, the Agency for Healthcare Research and Quality (AHRQ) solicited topic nominations for evidence reviews that were to be based on systematic, rigorous, and unbiased methods for selecting the literature and synthesizing the data through its network of 12 evidence-based practice centers.1 The evidence reviews can serve as a scientific foundation for developing and implementing clinical practice guidelines and related products. ASH and ASCO submitted to AHRQ a formal proposal for an evidence-based practice center review on the use of epoetin in cancer patients. AHRQ selected erythropoietin as one of the topics to be reviewed. The undertaking was awarded to the Blue Cross and Blue Shield Association Technology Evaluation Center (TEC) in Chicago, IL.2 ASH and ASCO established an independent panel of experts in clinical medicine, clinical research, health services research and related disciplines to develop an evidence-based guideline from the evidence review. A draft of the TEC report was made available to the panel in late 2000, and the final report was released publicly in May 2001. The full-text TEC evidence report, Use of Epoetin for Anemia in Oncology,3 and the Executive Summary can be obtained in print form from the AHRQ Publications Clearinghouse (800-358-9295) or online at www.ahrq.gov/clinic/epcix.htm. This report should be consulted by those interested in a more detailed treatment of the state of the evidence supporting the use of epoetin in clinical oncology practice than the information provided in this guideline. This document is the evidence-based clinical practice guideline developed by ASH and ASCO that is based on the review. The guideline is a blend of evidence, the opinions of experienced practitioners, and their interpretation of the evidence. ASH and ASCO acknowledge that guidelines cannot always account for individual variations among patients. Guidelines are not intended to supplant physician judgment with respect to particular patients or special clinical situations, and cannot be considered inclusive of all proper methods of care or exclusive of other treatments reasonably directed at obtaining the same results. Accordingly, ASCO and ASH consider adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in light of each patients individual circumstances. In addition, these guidelines describe administration of therapies in clinical practice; they cannot be assumed to apply to interventions performed in the context of clinical trials, given that clinical studies are designed to test innovative and novel therapies in a clinical situation where better therapy is needed. In that guideline development involves a review and synthesis of the latest literature, a practice guideline also serves to identify important questions for further research and those settings in which investigational therapy could be considered as an option. The following sections detail the methods used by the panel to develop its recommendations, the recommendations and the findings of the TEC report that influenced the panels conclusions, as well as suggestions for future research. A summary of the guideline recommendations can be found in Table 1.
Panel Composition ASH and ASCO established a joint guideline panel of experts in clinical medicine, clinical research, and health services research. Each organization nominated a cochair (A.E.L., M.S.G.), who then selected the panel members in consultation with the relevant officers of both organizations to achieve an appropriate distribution of content experts and practitioners. The first meeting of the 12 panel members was in May 1999. The panel included six academically affiliated and two community-based practicing hematology/oncology specialists, two experts in quality-of-life research, a practice guideline methodologist, and a patient representative. Two ex-officio members represented the relevant practice guideline committees of ASH and ASCO, and the project director for the TEC review joined the panel as an ex-officio member (Appendix A). One quality-of-life expert resigned and was replaced, and the first patient representative died during the project.
Conflict of Interest
Definition of Topic The outcomes of interest in evaluating the effectiveness of epoetin were to include requirements for transfused RBCs, changes in hemoglobin or hematocrit concentration, and quality of life. Although recommendations were not to be based on economic considerations, the panel did consider it important to review existing literature on the costs and cost-effectiveness of epoetin.
Review of Evidence In summary, the TEC searched MEDLINE, Cancerlit, and Embase databases for all relevant articles published since 1985. The TEC supplemented the above strategy by searching issues of Current Contents on Diskette and Medscape Oncology5 through October 30, 1999, to identify recently published articles that had not yet been indexed by the online databases. The reviewers also examined abstracts presented at the 1999 annual meeting of ASCO, bibliographic information and reprints of clinical studies provided by Ortho Biotech, Inc, and reference lists from relevant review articles, editorials, and letters published after 1994. Subsequently, the panel also reviewed emerging evidence on a new agent, darbepoetin, and kept abreast of other important emerging evidence that is cited in this document. Admissible evidence included controlled trials (randomized and nonrandomized) that compared the outcomes of managing anemia with and without the use of epoetin. All trials that met study selection criteria compared epoetin plus RBC transfusion as necessary with RBC transfusion alone. Studies had to include at least 10 similarly treated assessable patients in each arm, relevant strata, and relevant epoetin dose level. Studies that used nonrandomized concurrent or historical controls were included only if the reviewers were satisfied that patients in the treatment and control groups were comparable at baseline and that obvious selection bias was absent; however, it is acknowledged that the nature of such designs cannot completely protect against such biases. Two reviewers independently conducted each step in the review process. Disagreements were resolved by consensus. The TEC also conducted a pooled statistical analysis (meta-analysis) of the effect of epoetin on the odds of transfusion for patients with anemia or at risk of anemia primarily because of cancer therapy. The guideline panel relied mainly on the evidence review performed by TEC in developing the guideline. However, the panel, with acknowledgment of their design limitations, also included large community studies excluded by TEC because of methodologic concerns. A summary and critical appraisal of the studies reviewed for this guideline can be found in Tables 2 through 5 (chemotherapy-induced anemia) and Appendix B.
Process Overview The cochairs and a planning committee of ASH and ASCO representatives developed a joint operating structure for coordinating the work of the panel under the auspices of both organizations. Coordinated procedures were developed for defining the role of the cochairs, for panel selection, for addressing conflicts of interest, and for peer review and final approval of the document. The panel considered it essential to use a systematic review of the evidence as its foundation for making recommendations. This process includes a systematic weighting of the level of evidence and a systematic grading of the evidence for making a recommendation.6,7 The hierarchical grading system gives greater weight to well-designed randomized controlled trials and meta-analyses and progressively less weight to studies with weaker internal validity. When evidence was lacking, the panel determined that it was appropriate to reach conclusions based on expert opinion as long as it was acknowledged explicitly. The panel determined that consensus would be reached by majority vote. The strength of evidence and grade of recommendations were assigned according to the coding scheme in use by ASCO (Table 6).8 However, for clarity these are supplemented by narrative descriptions of the state of the evidence.
The panel met on several occasions. After developing procedures and reviewing the evidence as presented by the TEC report, draft recommendations were prepared and discussed in a face-to-face meeting before the completion of a full draft report. All panel members reviewed all iterations of the guideline, contributing feedback to the levels of evidence and the systematic grading of the data supporting the recommendations. Independent review from three external experts was obtained. The final content of the guidelines and the manuscript were reviewed and approved by the ASCO Health Services Research Committee and Board of Directors, as well as the Executive Committee of ASH.
General Recommendation As in any medical situation, it is essential to give consideration to other correctable causes of anemia before proceeding to therapy with stimulants of erythropoiesis. Therefore, it is advisable to conduct an appropriate history and physical and to consider relevant diagnostic testing aimed at identifying causes of anemia aside from chemotherapy or underlying hematopoietic malignancy. At a minimum, one should take a thorough drug exposure history, carefully review the peripheral blood smear (and in some cases, the bone marrow), consider iron, folate, and B12 deficiency where indicated, and assess for occult blood loss. Coombs testing may be appropriate for patients with chronic lymphocytic leukemia; endogenous erythropoietin levels may predict response in patients with myelodysplasia.
Chemotherapy-Induced Anemia
Level of evidence (status of evidence):
Grade of recommendation:
Rationale: Transfusion requirements: The difference in the percentage of adult patients requiring any transfusions between epoetin and control arms in the various trials ranged from 9% to 45% in favor of epoetin (Table 4). In four trials, the difference was reported as statistically significant10,13,14,16; however, many of these trials did not use intention- to-treat analysis. Some trials reported that patients receiving epoetin required fewer units of transfused RBCs compared with the control group; adults in the control groups of the trials required 0.6 to two units of RBCs per 4-week period, compared with 0.1 to two units for those rand-omized to epoetin, representing an absolute difference range of zero to 0.7 units of RBCs. The differences in transfused units were statistically significant in two trials.10,14 Meta-analysis confirmed a reduction in the relative odds of transfusion for those randomized to epoetin. The meta-analysis conducted by the TEC (see Appendix B), when applied to those randomized controlled studies that used subcutaneous epoetin and reported numbers of patients transfused, yielded a cumulative odds ratio of 0.38 (95% confidence interval [CI], 0.28 to 0.51), suggesting that use of epoetin decreases the relative odds of receiving a RBC transfusion by an average of 62% (Table 7). When the meta-analysis was restricted to data from studies meeting TEC criteria for higher quality, the odds ratio remained significant at 0.45 (95% CI, 0.33 to 0.62).
The relative odds of requiring transfusion can be translated into an absolute risk reduction, where this also depends on the baseline probability that the patient will require a transfusion. The TEC estimated the baseline risk of transfusion by using the control arms of trials that reported the proportion of patients transfused by 12 weeks of follow-up; this was applied to the relative risk reductions to determine absolute benefit. Using this approach, the TEC calculated an absolute benefit that corresponded to a number-needed-to-treat of 4.4 (95% CI, 3.6 to 6.1) in order to benefit one patient. (The number-needed-to-treat is the reciprocal of the absolute risk difference.) The estimated number-needed-to-treat, derived only from studies meeting TEC criteria for higher quality, was 5.2 (95% CI, 3.8 to 8.4). That number would be higher if the risk of requiring a transfusion were lower than that assumed by the TEC. Symptomatic improvement: Whether improvement in hemoglobin and reduction in transfusions with epoetin therapy translate into clinically meaningful symptomatic improvement requires further study. Some studies that have examined functional status or overall quality of life have produced inconsistent results or rely on data of variable methodologic quality (Table 5). Threats to validity of these trials include higher than usual dropout rates; among the trials that include quality of life as an outcome, 10% to 40% of the patients were not assessable at the end of the study. Quality-of-life studies can be difficult to conduct and, unlike transfusion or hemoglobin outcomes, depend on respondents completing surveys at distant time points. Therefore, missing data in quality-of-life studies does not necessarily represent neglect on the part of investigators. The largest randomized trial to date (total N = 375), though supporting a significant improvement in quality of life in the epoetin arm, does suffer from the problem of missing data, thus threatening the validity of the inferences that can be made.16 It is unclear whether this missing data had any significant effect on the distribution of quality-of-life outcomes between the treatment arms.17 Ideally, randomized studies of quality of life would be analyzed using intention-to-treat principles; however, research to identify proper methods for handling nonrandom missing data in quality-of-life studies is ongoing.17 Many studies used quality-of-life instruments that have only recently been introduced.18 Since the experience with these instruments is limited, research defining minimum clinically meaningful changes in quality-of-life scores is ongoing. In particular, psychometric research is underway to quantify the clinical impact associated with changes in the quality of life measured by one popular instrument, the Functional Assessment of Cancer TherapyGeneral questionnaire.19 Because the trials on which these conclusions are based are only of fair quality regarding quality-of-life outcomes (due to limitations in reporting and conduct of the investigations), the probability of false-positive and false-negative results cannot be assumed to be low (level II evidence, see Table 6). In making recommendations for use of epoetin, the evidence for improvements in hemoglobin and transfusions outcomes was considerably stronger then that for quality-of-life outcomes. Replication of quality-of-life improvements that are demonstrated to be clinically meaningful in other well-designed clinical trials would improve the strength of evidence and further support this recommendation. Dose and dose schedule of epoetin: Please refer to discussion below regarding optimal dose and dose schedule for administering epoetin.
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale: Transfusion requirements: Of the five trials that used as an outcome the percentage of patients requiring transfusion,21,22,24-26 the range of the difference in percent transfused was from 7% to 47%, all favoring epoetin (Table 4). The difference in the proportion of patients requiring transfusion was statistically significant in one of the five trials.25 Of the three studies that reported the number of units transfused, the differences between epoetin and control groups over a 4-week period ranged between 0.1 and 1.3 units per patient, all favoring epoetin. One trial24 reported that the reduction in transfused units was statistically significant, but the other two did not discuss statistical significance.25,26 In this trial,24 the dose of epoetin was among the highest used, 1,200 U/kg/wk.
The meta-analysis performed by the TEC, which pooled randomized trials for patients with all levels of hemoglobin at entry, did show a reduction in the relative odds of receiving a transfusion for those treated with epoetin. However, because study quality may confound the effect of baseline hemoglobin on the odds of transfusion, and because all of the studies considered to be of "higher quality" by the TEC enrolled patients with baseline hemoglobin Symptomatic improvement: No trials reported data to evaluate whether epoetin improves symptoms or quality of life specifically among patients with baseline hemoglobin levels of 10 to 12 g/dL (Table 5). Although one randomized trial reporting significant quality-of-life improvement with epoetin included patients with baseline hemoglobin levels of 10 to 12 g/dL, this group represented only 16% of all patients studied and outcomes were not presented for quality of life stratified by hemoglobin level.16 The panels ability to support a definitive recommendation is limited by the heterogeneity of the statistical significance of response outcomes. This heterogeneity may, in fact, be due to the small size of these trials. It is noteworthy, however, that the relative improvement in outcomes observed in these studies, although often not statistically significant, is consistent with the relative rates seen for patients with more severe anemia (baseline hemoglobin < 10 g/dL), and in all studies, including those that were placebo-controlled, the direction of the effect always favored epoetin. Unfortunately, the meta-analysis accounts for small sample sizes by pooling the data from many trials, but it could not be used to isolate the effect of epoetin on transfusion outcomes for specific baseline hemoglobin levels. The lower absolute risk for transfusions among patients with a baseline hemoglobin level of 10 to 12 g/dL limits the absolute probability of benefit (and the statistical power of published trials to demonstrate such a benefit) in this population. The recommendation for use of epoetin in patients with baseline hemoglobin levels of 10 to 12 g/dL based on clinical judgment is premised on the assumption that patients with specific comorbid conditions face a higher absolute probability of anemia or a higher risk of adverse events related to this degree of anemia than do other patients with this hemoglobin concentration. Examples of patients at this higher degree of absolute risk, who may be considered reasonable candidates for this agent, based on clinical judgment, include but are not limited to elderly individuals with limited cardiopulmonary reserve or patients with underlying coronary artery disease and symptomatic angina.
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale: Because the multiple-arm studies detecting improvements in hemoglobin and transfusion outcomes favoring epoetin have based dosing on a three times weekly regimen, the most compelling evidence for use of epoetin supports a thrice-weekly regimen. However, for convenience of patients, common clinical practice has evolved to once-weekly dosing. Pharmacokinetic studies suggest that once-weekly dosing intervals with higher doses of epoetin achieves similar rises in reticulocyte counts when compared with three-times-weekly intervals.28,29 Though both are randomized controlled trials, they are small (< 40 persons), involve normal volunteers, and are descriptive in nature (not powered to detect statistical significance). A large, nonrandomized, community-based study using once-weekly dosing has reported improvements in hemoglobin and quality of life similar to those with thrice-weekly dosing.30 In addition to lacking a concurrent control comparison, the study has been criticized because of lack of adjustment for potential baseline confounding variables and for its handling of the relatively large dropout rate.31 No randomized controlled trials have yet been reported to substantiate or contradict the outcome of once-weekly epoetin versus thrice-weekly treatment. A randomized trial comparing once-weekly epoetin dosing with a placebo control arm has completed accrual and was presented as an abstract in May 2002.32 The preliminary results suggest that weekly epoetin increases hemoglobin concentrations and decreases transfusion rates compared with placebo among patients receiving chemotherapy. Another pharmaceutical erythropoiesis-stimulating protein that requires less frequent dosing (darbepoetin alfa) is also being tested in randomized trials to confirm the data from dose-finding studies,33 which suggest it can be administered effectively as infrequently as once per chemotherapy cycle. Comparative studies are in progress to evaluate darbepoetin in patients with cancer. Table 8 lists the ongoing studies and preliminary reports available to the panel at the time of this writing regarding darbepoetin.34-38
The preliminary results for the effectiveness of darbepoetin alfa from these studies are sufficiently promising to justify ongoing assessment by the panel. Preliminary results not yet reported as published peer-reviewed studies can be a useful complement to fully published studies when making a clinical recommendation. However, because preliminary results are the only data available in this case, and reasonable alternative therapy already exists, the panel chose the prudent course of waiting until such studies are published before committing to a clinical recommendation about darbepoetin. The panel will add to the current recommendations in a timely manner once such data become available.
Dose escalation and duration: In studies using subcutaneous epoetin, the most common initial dose was 150 U/kg administered three times weekly. The most common higher starting dose was 300 U/kg three times weekly. Among studies using subcutaneous epoetin at these lower dose ranges (300 to 450 U/kg/wk), four trials increased the dose for nonresponders after a fixed period of time, four decreased the dose for responders, and four used a fixed and continuous dose throughout treatment. The criteria for dose escalation were typically a combination of failure to achieve at least a 1 g/dL rise over baseline hemoglobin and a reticulocyte count less than 40,000/µL by the fourth week of treatment. Treatment duration was more than 20 weeks in six trials, 12 to 16 weeks in eight trials, and Weight-based versus uniform dosing: Most trials reviewed by the TEC utilized weight-based epoetin dosing regimens (Table 2). Recently, some single-arm studies have shifted to uniform dosing (10,000 units three times weekly, 40,000 units once weekly).30,39 No randomized trials have directly compared weight-based dosing with uniform dosing. Subcutaneous versus intravenous administration: Virtually all studies evaluating the effectiveness of epoetin have used subcutaneous administration. Intravenous administration has been used in only three studies (98 patients),23,24,40 limiting the ability to make a specific recommendation. No study included in this report compared intravenous with subcutaneous administration. Evidence from hemodialysis patients suggests that subcutaneous administration is 30% to 50% more efficient than the intravenous route.41,42
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale:
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale: It should also be considered that in a large (N = 1,233) prospective clinical trial of patients with chronic renal failure and concurrent cardiac disease treated with epoetin, patients randomized to achieve a target hematocrit of 42% were shown to have higher mortality than those randomized to a target of 30%.45 The trial was designed with 90% power to detect a 20% difference (two-sided) in survival or time to first nonfatal myocardial infarction between the two groups using intention-to-treat analysis. It was discontinued at its third interim analysis when patients in the normal hematocrit group were found to have a higher event rate (relative risk, 1.3; 95% CI, 0.9 to 1.8) than patients in the low-hematocrit target group. Although this result was not statistically significant, the study monitors believed that it was very unlikely that continued accrual to the study would reveal a benefit for the normal hematocrit group. As well, in posthoc analysis it was shown that those in the normal hematocrit group had less adequate dialysis and greater iron chelation therapy than the control group, which may have contributed to the higher mortality rates. A substantial proportion of patients who receive epoetin report adverse events. Of the 10 studies reporting any adverse event among the 1,155 patients, the rate was 46% among the controls and 56% among the epoetin-treated groups.3 These complications, however, are often reasonably ascribable to concurrent treatments or to the underlying disease. Most of the trials examined for this guideline evaluated relatively few patients. Trials powered to detect specified differences in main outcomes may not have sufficient power to detect adverse events that are less frequent. With relatively few patients in each study arm, differences in adverse events in these trials are unlikely to achieve statistical significance.
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale:
Myelodysplasia, Multiple Myeloma, Non-Hodgkins Lymphoma, and Chronic Lymphocytic Leukemia (anemia primarily related to hematologic malignancy)
Level of evidence (status of evidence):
Grade of recommendation:
Rationale:
Myelodysplasia:
Myeloma, lymphoma, and chronic lymphocytic leukemia:
In the five trials reviewed by the TEC, all patients were adults with mean or median hemoglobin levels
All five trials reported the percentage of patients who had a hematologic response. More patients randomized to epoetin responded (31% to 75% for those given
Transfusion outcomes were reported in only the two multiarm trials.52,53 One trial reported significantly fewer patients transfused in the epoetin arms than in the control group (58% to 64% v 82%) but no significant reduction in the number of units of RBCs transfused.53 The other trial reported fewer patients transfused (15% to 19% v 27%) and fewer units transfused (0.2 to 0.5 v 0.9) in the arms given With one exception,51 no studies reported outcomes with respect to quality of life, symptoms of anemia, number of days in hospital, or changes in performance status. The study of patients with chronic lymphocytic leukemia reported significantly improved energy levels in the epoetin-treated group but did not describe the quality-of-life instrument or other methodologic details for evaluating the validity of the data.51 The abstract reported that epoetin-treated patients who achieved a hematocrit of 38% showed significant improvements in energy, self-rated health, physical function, role function/physical, role function/emotional, social function, and mental health. There is inadequate detail in the abstract to evaluate whether results were confounded by or adjusted for tumor response, rise in neutrophil count, or the administration of iron, B12, or folic acid supplements. Methodologic and reporting weaknesses exist for all of the studies involving anemia directly related to myeloma, non-Hodgkins lymphoma, and chronic lymphocytic leukemia and not induced or complicated by chemotherapy, limiting the strength of the evidence supporting these recommendations.
Recommendation:
Level of evidence (status of evidence):
Grade of recommendation:
Rationale:
Future research priorities for epoetin include not only the need to answer specific questions about the effectiveness, indications, and optimal treatment protocols for using the drug and to explore similar questions for newer erythropoiesis stimulants, but also the need to incorporate specific design features to address the limitations of prior trials. For example, it is important for studies to have adequate sample size to achieve sufficient statistical power to demonstrate a significant effect on outcomes, including secondary outcomes such as quality of life. Prospective plans for handling dropouts/missing data for outcomes anticipated to be problematic (quality of life, adverse reactions) should be incorporated. Past trials have sometimes been deficient in defining and documenting critical information about the study population and its baseline health status and clinical history, details of treatment protocols for each study group, especially concomitant chemotherapy, and specification and validation of outcome measures relied on to infer an effect. Even some randomized trials have not been attentive to using (or documenting) proper methods of randomization, concealment of allocation, and blinding. Documentation of dropouts and other sources of attrition, including the reasons for withdrawal and the number of cases, has also been inadequate. Trials examining the effect of epoetin on quality of life have used recently developed instruments whose validity is still being established, sometimes with incomplete documentation of their content, performance characteristics, or clinical relevance. Statistical analyses have often disregarded intention-to-treat analysis or have engaged in excessive posthoc data analysis, which for statistical reasons tends to increase the identification of significant associations by chance. Unanswered questions remain as to whether increases in hemoglobin to levels above 12 g/dL are of clinical benefit. One complicating factor in defining the optimal target hemoglobin level is the recognition that the normal ranges for hemoglobin levels in men and women are different and, hence, that sex-specific norms are needed. Ideally, studies would define entry criteria based on these norms and report outcomes based on hemoglobin level at study entry. Uncontrolled cohort studies suggest that rises in hemoglobin above the 12-g/dL point are associated with a continued, though attenuated, improvement in quality-of-life parameters.39,44 Randomized controlled trials evaluating the optimal hemoglobin target will be required to answer this question. Additional studies should also be initiated to define better the appropriate hemoglobin level at which to begin epoetin therapy based on sex-specific norms mentioned above. One trial design which may address this would be a direct randomized comparison of one group for which treatment begins as soon as they go below hemoglobin of 12 g/dL versus another group for which treatment does not begin until they get close to 10 g/dL (definitely below 10.5 g/dL). Further research regarding the effectiveness of once-weekly dosing regimens is necessary. While shown to be effective in a large, single-arm, nonrandomized study,30 once-weekly regimens have not been compared in a randomized study with appropriate three-times-weekly regimens or placebo. Optimally, epoetin or other erythropoiesis-stimulating pharmaceuticals intended to be given weekly or less frequently will be directly compared with three-times-weekly administration programs for effectiveness in randomized trials. Such phase III randomized trials appear to be underway for both epoetin and darbepoetin. The proper role for iron supplementation in epoetin-treated patients is unknown. Aside from monitoring iron levels, more recent clinical experience has suggested that rises in hypochromic RBCs and high levels of soluble serum transferrin receptor may indicate the early need for iron supplementation. The optimal form of iron is unsettled as well. When iron supplementation was reported in the clinical trials reviewed, oral supplementation was most common. Oral iron is associated with gastrointestinal side effects, whereas hypersensitivity reactions limit parenteral use. Newer forms of parenteral iron, associated with significantly fewer anaphylactic reactions, are now being used to treat patients with severe iron deficiency. With this in mind, the optimal schedule for iron repletion is unclear, with some clinicians favoring complete replacement at baseline and others advocating weekly infusions to enhance the amount of available circulating iron.
It has been hypothesized that anemia may have some physiologic effects that should be evaluated as "harder" end points of potential clinical benefit. These end points include effects on respiratory function as demonstrated by measurements of
No trial to date has adequately defined the baseline prognostic factors that predict response to epoetin. Parameters such as circulating cytokine levels (eg, tumor necrosis factor-alpha) have been hypothesized as potentially limiting the response to epoetin,57-59 but this has not been evaluated in a controlled trial. Prospective evaluation of baseline erythropoietin levels as predictors for response to epoetin should be undertaken. There is little firm evidence to support the contention that transfusion-dependent patients respond less dramatically to epoetin. Further work is needed to expand the outcomes of interest in evaluations of epoetin beyond transfu-sion parameters, such as validating improved measures of quality of life, and clinical surrogates such as cognitive function and respiratory function ( One trial suggests a survival advantage for patients treated with epoetin, but the study was not adequately powered to test this hypothesis.16 Further research is needed to determine whether higher hemoglobin levels improve survival or whether, in some manner, epoetin potentiates the antitumor effects of chemotherapy. Children are relatively underrepresented in the studies reported to date that evaluate the effectiveness of erythropoietin. Only three studies reviewed by the TEC involved treatment-related anemia in children.40,60,61 Whether this can be attributed to a belief that children tolerate symptoms and side effects better or experience them less often is not known. Certainly future investigation could focus more attention on the clinical effectiveness and quality-of-life changes that children may experience with epoetin. No available studies have evaluated the costs of administering epoetin, an analysis complicated by the need to incorporate the indirect costs of transfusions. A series of ongoing and recently completed trials are expected to provide relevant economic data. Ultimately, cost-effectiveness/cost utility analyses should be pursued.
Detailed Summary of Evidence Incorporated in Guideline Development The details of the evidence reviewed by the TEC are available in its full report and reviewed in a journal article.3,4 The important highlights are summarized here as they relate to the recommendations provided in the guideline.
CHEMOTHERAPY-INDUCED ANEMIA
Quality of Evidence
Adequacy of randomization (comparability of groups).
Heterogeneity/ambiguity of cancer treatment regimens.
Heterogeneity/ambiguity of confounders.
Heterogeneity/ambiguity of epoetin treatment.
Heterogeneity/ambiguity of RBC transfusion policies.
Limitations in outcome measures. No trial reported on symptoms of anemia (eg, dyspnea, angina) or number of days in hospital. The only trial that reported changes in performance status used the Karnofsky scale.60 Of the nine studies that measured quality of life or the components (eg, energy level) that are associated with quality of life, only seven compared pre- and posttreatment scores between epoetin and control arms, and five met the TEC criteria for higher quality. Two studies9,27 made before-and-after comparisons of quality-of-life measures within treatment arms but did not compare results between arms. None of the studies reported the features considered important for minimizing bias in measuring quality of life (eg, procedures to minimize the impact of other factors on response to quality-of-life instruments, handling of missing data). No study prospectively defined the minimum differences in quality-of-life scores that would be considered clinically significant, which may limit the ability to interpret the implications of any statistically significant differences that were observed. It should be noted that for some quality-of-life instruments, active research is ongoing to define minimum clinically meaningful differences.19 In many studies, as many as 10% to 40% of randomized patients were excluded from quality-of-life outcomes because of missing data, and intention-to-treat analysis was not performed. The potential bias introduced by this attrition is that the subset of treatment and control patients, no longer consisting of the originally randomized groups, may differ in characteristics other than epoetin treatment that could influence answers to quality-of-life questions. Unfortunately, this problem is not unique to epoetin. Quality-of-life studies may be more difficult for patients to complete, often causing dropout rates for quality-of-life outcomes in clinical trials to be higher than for other outcome measures.
Statistical methods.
Summary of Results
Community Studies
Meta-Analysis The relative odds of requiring transfusion can be translated into an absolute risk reduction, where this also depends on the baseline probability that the patient will require a transfusion. The TEC estimated the baseline risk of transfusion from using the control arms of trials that reported the proportion of patients transfused by 12 weeks of follow-up; this was applied to the relative risk reductions to determine absolute benefit. Using this approach, the TEC calculated an absolute benefit that corresponded to a number-needed-to-treat of 4.4 (95% CI, 3.6 to 6.1) in order to benefit one patient. (The number-needed-to-treat is the reciprocal of the absolute risk difference.) The estimated number-needed-to-treat, derived only from studies meeting TEC criteria for higher quality, was 5.2 (95% CI, 3.8 to 8.4). That number would be higher if the risk of requiring a transfusion were lower than that assumed by the TEC.
ANEMIA DUE PRIMARILY TO MALIGNANT DISESASE (myelodysplasia, myeloma, non-Hodgkins lymphoma, and chronic lymphocytic leukemia)
The TEC review identified two randomized controlled trials examining the use of epoetin in myeloma only,49,50 a randomized study of patients with chronic lymphocytic leukemia that is available only as an abstract,51 and two randomized trials involving myeloma and non-Hodgkins lymphoma/chronic lymphocytic leukemia.52,53 Each of these studies included patients receiving concurrent therapy for their malignancy. One randomized controlled trial reports on results of epoetin therapy in patients with myelodysplastic syndrome; none of these patients received concurrent therapy.48 The combination of diverse disease groups in the former trials complicates interpretations. Several publications from an additional randomized controlled trial54-56 were excluded from detailed TEC analysis because of incomplete reporting by the investigators and will not be discussed here. In the six trials reviewed by the TEC, all patients were adults with mean or median hemoglobin levels Transfusion history differed across studies. Three studies reported on patient groups who had received prior transfusions (n = 222) and in three studies 0% to 20% of patients had received previous transfusions. Three studies used iron supplementation (n = 304), and three studies did not specify whether patients were supplemented. Since the failure to rule out other causes of anemia, including iron deficiency, might lead to underestimating the effects of epoetin, the TEC used stringent criteria to assess verification of iron status. Four trials met these criteria.48,50,52,53
Quality of Evidence Three trials48,50,53 specified the threshold for administering RBC transfusions (7 to 10 g/dL), but in the other three trials,49,51,52 the trigger was unspecified and left to the discretion of the treating physician. Ambiguities in the extent to which the various study arms received transfusions make it unclear to what extent observed outcomes were ascribable to epoetin. Finally, comparing hematologic treatment responses across trials is difficult because investigators used inconsistent definitions for "complete response."
The expert panel expresses its gratitude to the family of patient representative Dr Suzanne Fleischman from Berkeley, CA, the original patient representative who died before this guideline was finalized. The panel also acknowledges Drs Sam Silver, Jerry Spivak, Lawrence Goodnough, Marcy List, and Peter Wiernik for their reviews of the guideline, as well as Mark R. Somerfield of ASCO and Maurice P. Mayrides of ASH for their assistance.
Adopted May 17, 2002, by the American Society of Clinical Oncology. Adopted April 18, 2002, by the American Society of Hematology. This article was published ahead of print at www.jco.org.
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