Consensus Guidelines for the Conduct and Reporting of Clinical Trials in Systemic Light-Chain Amyloidosis

REVIEW Consensus guidelines for the conduct and reporting of clinical trials in systemic light-chain amyloidosis

RL Comenzo1, D Reece2, G Palladini3, D Seldin4, V Sanchorawala4, H Landau5, R Falk6, K Wells7, A Solomon7, A Wechalekar8, J Zonder9, A Dispenzieri10,MGertz10, H Streicher11, M Skinner4, RA Kyle10 and G Merlini3

This manuscript summarizes the recommendations that emerged from the ﬁrst Roundtable on Clinical Research in Immunoglobulin Light-chain Amyloidosis (AL), a meeting sponsored by the Amyloidosis Foundation (Clarkston, MI, USA) to develop a consensus of experts on a modern framework for clinical trial design and drug development in AL. Recent diagnostic and technical advances in AL, and updated consensus guidelines for assessing hematologic and organ responses, enable us to deﬁne study populations, appropriate end points, and other criteria for all phases of clinical research. This manuscript provides a framework for the design and conduct of systematic collaborative clinical research in AL to encourage more rapid testing of therapies and to expedite new drug development and approval.

Leukemia (2012) 26, 2317–2325; doi:10.1038/leu.2012.100 Keywords: amyloidosis; free light chains; clinical trials; clinical research

INTRODUCTION and directly cause organ toxicity and form amyloid deposits, leading 3 Systemic immunoglobulin light-chain amyloidosis (AL) is the most to organ failure and death, often from cardiac involvement. In some common type of systemic amyloidosis with an estimated cases, the tempo of disease can be rapid with an interval of months 4 incidence of 8–10 cases per million person-years.1,2 Although between diagnosis and death. Two-thirds of AL patients present there have been recent advances in AL, there is a major need for a with one or two major organ systems involved (heart, kidneys, liver/ framework for clinical research to encourage the development of GI tract, peripheral nervous system and soft tissues) while a third of 2 new therapies. Access to novel agents and their optimal and safe patients presents with more than two systems involved. Symptoms use are challenges for patients with this rare disease. Well-designed reflect involved organ disease. Both the clonal plasma cells and the clinical trials with multicenter collaboration will accelerate timely pathologic light chain proteins are targets for therapy in AL. testing of novel agents and combinations, will improve access and Unlike multiple myeloma, morbidity and mortality in AL are due will accelerate pharmaceutical company efforts and acceptance by to the devastating effects of the toxic monoclonal protein not payers. We in the United States are heartened by the continued to the proliferation of monoclonal plasma cells. Nonetheless, interest and support of the National Cancer Institute study groups, therapies that eliminate monoclonal plasma cells (similar to those particularly the Southwest and Eastern Oncology Groups, in employed in multiple myeloma) ameliorate AL disease because developing phase II and III trials for patients with AL, and in the they can remove the factory producing the toxic proteins. Most European Union by the collaboration of national plasma-cell patients die of complications of cardiac dysfunction due to disease networks and of the European Myeloma Network. These monoclonal light chains, and survival in AL depends upon rapid efforts should be complemented by the development of a phase I suppression of the synthesis of the monoclonal proteins and pipeline to nurture the development of phase II and III trials. stabilization or recovery of heart function.5,6 In this consensus report, we review distinctive aspects of AL that The necessity to translate hematologic response into cardiac impact trial design, recent important advances in AL, the definitions of and other organ responses to improve quality of life (QOL) and hematologic and organ response in AL and their implementation in extend survival requires the combined evaluation of both clonal clinical trials, the heterogeneity of the study populations among AL and organ responses and raises several problems unique to AL. patients and the end points relevant to the design of clinical trials. We For example, although the hematologic response is a prerequisite hope that our comprehensive detailed overview will serve to inform for improving outcome, this is dependent upon the extent of the the design and implementation of collaborative clinical trials. organ damage and its reversibility. Patients with very advanced cardiac damage at high risk of progressive heart failure and sudden death may not be rescued by effective anti-plasma cell DISTINCTIVE FEATURES OF AL therapy. Efforts should be made to identify these patients, The distinctive features of AL have significant implications for representing up to 20% of the patients in referral centers, who clinical trial design and drug development. AL involves monoclonal should then be considered for alternatives such as orthotopic plasma cells productive of immunoglobulin light chains that misfold heart transplantation.7 It is therefore necessary to stratify patients

1Division of Hematology/Oncology, Tufts Medical Center, Boston, MA, USA; 2Princess Margaret Hospital, Toronto, Ontario, Canada; 3Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy; 4Boston University School of Medicine, Boston, MA, USA; 5Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 6Brigham and Women’s Hospital, Boston, MA, USA; 7University of Tennessee Graduate School of Medicine, Knoxville, TN, USA; 8University College London, London, UK; 9Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA; 10Mayo Clinic, Rochester, MN, USA and 11National Cancer Institute, Washington, DC, USA. Correspondence: Dr RL Comenzo, Division of Hematology/ Oncology, Tufts Medical Center, Blood Bank and Stem Cell Processing Laboratory, 800 Washington Street, Boston, MA 02111, USA. E-mail: [email protected] Received 24 January 2012; revised 19 March 2012; accepted 20 March 2012; accepted article preview online 5 April 2012; advance online publication, 15 May 2012 Clinical research for AL RL Comenzo et al 2318 according to the extent of cardiac damage and prioritize appropriate investigational approaches. In AL unlike in myeloma, achieving a partial hematologic response or stable disease may not offer a clinical beneﬁt as ongoing light chain production may result in further organ damage. Partial response (PR) should always be viewed in conjunction with organ response in the evaluation of treatment outcomes, and stable hematologic disease is not an innocuous category of response in AL because of the risk of organ-disease progression. This makes the concept of time-to-next therapy as a clinical research end point of limited utility, unlike in multiple myeloma.

RECENT ADVANCES IN AL Definitive typing To diagnose amyloidosis, tissue biopsy of either an involved organ or a surrogate site (for example, abdominal fat) must demonstrate amyloid deposition by Congo red staining or by electron Figure 1. Patients in this international case series from seven micrographic identification of pathognomonic fibrils.8 Once the centers were analyzed for survival at 3 months after beginning diagnosis of amyloidosis has been made, the clinician must therapy based on metrics for hematologic response assessed determine the type of amyloidosis that is present. If the work-up at 6 months. In this series, 43.6% received oral melphalan and reveals a monoclonal protein, then the type is most probably AL; dexamethasone (MDex), 11.4% SCT, 22% immunomodulatory agent- based therapy and 3% bortezomib and dexamethasone. Response however, the possible coexistence of a monoclonal gammopathy criteria are CR (immunofixation negative and FLC normal); very and hereditary or age-related systemic amyloidosis should always 9 good PR (very good partial; reduction in the dFLC to o40 mg/l); be considered. If the work-up does not reveal a monoclonal PR (partial; reduction in the dFLC by 450%); and NR (no response; gammopathy, then the AL type is unlikely and evaluation for other less than PR).20 types should commence. Transthyretin amyloidosis (ATTR) is next most common, caused by either mutant (hereditary) variants (ATTRm) or the age-related variant due to wild-type transthyretin (ATTRwt).10 Secondary abnormalities associated with clonal plasma-cell diseases should be performed, and Congo red staining is necessary to identify amyloidosis, a type associated with inflammation, although rare 15–17 in the developed world, still occurs in association with amyloid. Use of the FLC assay has significantly changed the way that autoimmune diseases, malignancies and chronic infections. 18 Because clinical presentations are similar for the common types, patients with AL are diagnosed and monitored. The serum FLC assay is critical for evaluating patients with AL, as many patients one cannot infer the type of amyloid in a given patient. And 19 because monoclonal gammopathies of undetermined significance lack a measurable circulating intact immunoglobulin. FLC levels are increasingly common with age, the possibility that a patient and ratios are abnormal in 90% of AL patients, and the elevated with amyloidosis may have two potential precursor proteins FLC usually is the amyloid precursor protein. New criteria for needs to be appreciated.11 DNA sequencing of genes related to response of the hematologic disease have been developed based on the FLC assay, and significant decreases in the pathologic or hereditary variants is useful after the type of amyloid has been 20 identified both as confirmatory testing for the patient and as a involved FLC (iFLC) are associated with better survival (Figure 1). key screening test for the patient’s kindred.9 Although FLC measurement is a mainstay in the care of patients Immunoelectron microscopy has proven to be more reliable with AL, several analytical problems, such as lot-to-lot variation in 12 immunoreactivity of individual monoclonal FLC, lack of linearity in than immunohistochemistry for typing amyloidosis. Laser 21 microdissection with mass spectrometry (LMD/MS) is a recent dilution and high imprecision have been reported. Given the advance in diagnostic testing that identifies the type of amyloid vital role had by this assay in AL, clinicians and researchers should with high reliability and accuracy.13 An MS-based proteomic be aware of these limitations. We encourage support for a quality approach has also been developed for the direct analysis of the assurance program based on sample sharing within the national abdominal fat aspirate.14 Amyloid tissue typing is specifically networks conducting phase III clinical trials in AL. indicated in cases where two potential amyloid precursor proteins are present. Such cases include patients with monoclonal Cardiac biomarker staging gammopathies who are African-American or elderly men, or who have dominant peripheral or autonomic neuropathy, family Staging for cardiac involvement is also a critical part of the initial histories of amyloidosis or coexisting inflammatory disorders. evaluation. The cardiac risk assessment model represents another recent advance that has helped to standardize the evaluation of African-Americans have higher rates of monoclonal gammo- 22 pathies and a 4% incidence of the gene causing an ATTRm AL patients. The presence and character of cardiac involvement variant (Val122Ile). Elderly men also have higher rates of both at diagnosis remains a major prognostic factor for all AL patients; indeed, it appears that all AL patients have a degree of cardiac monoclonal gammopathies and age-related ATTRwt. These 23,24 patients almost always have one type of amyloid causing their involvement at diagnosis even if asymptomatic. Cardiac disease which can be reliably identified using proteomic-based events are the most common cause of death in AL patients. methods available at referral centers. Patients with cardiac involvement can present with fatigue, progressive dyspnea on exertion, diastolic dysfunction, left ventricular hypertrophy in the absence of hypertension or Free light chain measurements valvular disease, pericardial effusion, and low voltage on electro- Serum free light chain (FLC) studies and serum and urine cardiogram.25 The cardiac biomarkers N-terminal prohormone immunofixation are essential and, in conjunction with bone of brain natriuretic peptide (NT-proBNP)26 and troponin T (or I)27 marrow immunohistochemistry (CD138, kappa and lambda), can are prognostic with respect to survival in AL patients, and a system establish clonality. Fluorescent in-situ hybridization to look for incorporating these biomarkers is currently in use, with patients

Leukemia (2012) 2317 – 2325 & 2012 Macmillan Publishers Limited Clinical research for AL RL Comenzo et al 2319 Table 1. Prognostic factors, thresholds and staging for newly diagnosed AL patients

Year (Reference) Prognostic factors Patients (N) Thresholds Categories or stages Median survivals (months)

2003(ref. 26) NT-proBNP 152 o152 pmol/l Below Not reached 4152 pmol/l Above 9 2003(ref. 27) cTnT 261 Continuous risk score 1 21.7 Urine M-spike 2 15.8 Age 3 3.2 Ejection fraction 4 1.4 5 o1 2004(ref. 22) NT-proBNP 242 oor4332 ng/l I 26.4 cTnT o or4 II 10.5 0.035 mg/l III 3.5 2010(ref. 23) hs-cTnT 171 o77 ng/l Baseline Not reached 477 ng/l 10.6 NT-proBNP Decrease of 30% and 4300 ng/l At 6 months of therapy Not reached Increase of 30% and 4300 ng/l 20 2012(ref. 17) Relative 53 o0.243 CCND1 À Not reached Cyclin D 1 (CCND1) levels 40.243 CCND1 þ 26 months in CD138 þ plasma cells 2012(ref. 28) NT-proBNP 810 41800 pg/ml I 94.1 cTnT 40.025 ng/ml II 40.3 FLC-diff 418 mg/dl III 14 IV 5.8 Abbreviations: NT-proBNP, N-terminal prohormone of brain natriuretic peptide; cTnT, cardiac troponin T; hs-cTnT, highly sensitive cTnT; FLC-diff, the difference between the uninvolved free light chain subtracted from the involved free light chain measured by the serum FLC assay. assigned to stage I, II or III based on the presence of 0, 1 or 2 of Recently, the tetracycline analog doxycycline has been shown to these biomarkers exceeding threshold levels with reported disrupt light chain fibrils in vitro and to reduce AL amyloid median survivals of 26.4, 10.5 and 3.5 months, respectively.22 deposition in a transgenic mouse model of AL.31 This class of Recent experience with this staging system on the phase III compounds also warrants study in patients. level has raised concerns about exclusion of stage III patients from trials when there may be a subset of stage III patients with better survival. Re-examinations of overall prognostic approaches to HEMATOLOGIC AND ORGAN RESPONSE CATEGORIES newly diagnosed patients continue to emerge, including ones that Hematologic responses employ variables related to new cardiac biomarkers and to the Because AL has features of both a clonal hematologic disorder plasma-cell disease in AL such as cyclin D1 expression levels in and a multisystem organ disease, the assessment of disease and clonal plasma cells and the numerical difference between iFLC 17,23,28 response to therapy in AL is more complex than in multiple and uninvolved FLCs (Table 1). These retrospective efforts myeloma. Assessments of response to therapy must be objective are particularly useful for the interpretation of phase II clinical trial and have validated links to clinical benefit such as functional results in the newly diagnosed when prognostic data are available improvement, progression-free survival (PFS) and overall survival but, as survival improves with new treatments and as new (OS). Modern response criteria in AL grew out of the experience diagnostics become available, they must continue to be updated. with autologous stem cell transplant (SCT) against the backdrop of criteria defining AL organ involvement and improvement Anti-amyloid therapy with therapy.32,33 Because patients post-SCT frequently achieved Novel approaches have been recently developed targeting the profound complete hematologic responses with improved organ amyloid deposits and promoting their reabsorption. Immunother- function, the objective scoring of hematologic and organ apeutic approaches that impair the capacity of misfolded iFLC to responses was deemed important in the 2005 consensus be toxic or to aggregate and form fibrils are currently in testing. opinion of AL investigators.34 Questions of validation were not Passive immunotherapy with a murine IgG1 anti-human light addressed at that time and the criteria referred specifically to chain monoclonal antibody, designated as 11-1F4, which recog- newly diagnosed patients. nizes a conformational epitope present on generic amyloid With such questions in mind, investigators participating in the fibrils but not on the soluble amyloidogenic precursor protein, 2010 consensus committees of the XII International Symposium represents one such approach to disease treatment.29 Under on Amyloidosis pooled 816 patients with systemic AL from an exploratory phase I investigational new drug exemption, the 7 referral centers in the United States and European Union to safety and biodistribution of 124I-m11-1F4 in AL patients has been refine and validate the criteria for hematologic and cardiac determined. Organ-specific uptake in patient tissues has been responses to treatment in newly diagnosed patients based on demonstrated and the agent has been used for cardiac-gated survival analyses. At this time, both hematologic and cardiac acquisition of positron emission tomography imaging which may response criteria in newly diagnosed patients to initial therapy guide selection of patients for future immunotherapy using the have had their relationship to OS validated in the 2010 consensus chimerized or humanized form of this antibody. landmark analyses (Figures 1 and 2).20 In a mouse model of secondary amyloidosis, the clearance of The basis for hematologic response assessment is the serum amyloid deposits can be promoted by combining a small FLCs as measured by nephelometry. The cutoffs of FLC percent palindromic drug capable of clearing serum amyloid P-component reduction and absolute values achieved with initial therapy from the blood stream followed by treatment with anti-serum that best predicted survival and death within 12 months were amyloid P-component antibodies to opsonize fibrils for phagocy- identified by means of a series of receiver operator characteristic tosis.30 It is possible that this approach could be applicable to AL. curve analyses.20 Measurements of the traditional M protein were

& 2012 Macmillan Publishers Limited Leukemia (2012) 2317 – 2325 Clinical research for AL RL Comenzo et al 2320 neither as comprehensive nor as useful as FLC measurements the disease. In addition, even in the 17% of patients (135/816) with because the majority of AL patients do not have M proteins on measurable M proteins at baseline surviving at 6 months after serum or urine protein electrophoresis and because the iFLC cause starting therapy, the M-protein response did not improve survival in those not attaining an FLC response. With deference to the needs of both statistical uniformity and standardization of response assessments on clinical trials of newly diagnosed patients, a difference between the iFLC and uninvolved FLC of 50 mg/l was defined as assessable or measurable for response.20 The criterion using this difference, the difference between iFLC and uninvolved FLC (dFLC), covers about 85% of newly diagnosed AL patients. A 50% reduction in dFLC is considered as a PR, a reduction in the dFLC to o40 mg/l a very good PR, and normal FLC levels with a normal kappa/lambda ratio and negative serum and urine immunofixation studies an amyloid complete response (CR) (Figure 1). For the 15% of patients with AL and normal FLC or dFLC o40 mg/dl at baseline, standard criteria of response used in myeloma are available. M proteins 4500 mg/dl by electrophoresis are generally considered as assessable for response, and serum and urine immunofixation identify the monoclonal component in a high proportion of patients; in such cases, the full range of newly defined FLC response categories would not be available. Newly diagnosed patients who do not achieve a response to initial therapy are categorized as non-responders and are viewed as refractory. Criteria for progression of both organ and Figure 2. In the international series of 816 patients from 7 centers, hematologic disease were defined in the 2005 consensus opinion staging cardiac biomarkers were available for 53% (432/816). Of (Tables 2 and 3). With respect to the role of bone marrow these, 24% were stage 1 (both NT-proBNP p332 ng/l and cardiac examination in the definition of hematologic CR, although we troponin T (cTnT) p0.035 ng/ml or cTnI p0.1 ng/ml), 52% stage 2 (NT-proBNP 4332 ng/l or cTnT 40.035 ng/ml or cTnI 40.1 ng/ml), agree that a bone marrow plasma-cell test for clonality is and 24% stage 3 (both NT-proBNP 4332 ng/l and cTnT 40.035 ng/ml reasonable to confirm CR in patients on clinical trials, the 2010 or cTnI 40.1 ng/ml). In these survival curves, results for 377 patients consensus opinion, based on results in three dozen patients with baseline NT-proBNP greater than or equal to 650 ng/l are shown achieving CR with marrow examinations, did not support this according to NT-proBNP response or progression at 6 months.20 requirement across the board.

Table 2. Organ response and progression criteria

Organ Response Progression

Heart NT-proBNP response (430% and 4300 ng/l decrease in NT-proBNP progression (430% and 4300 ng/l increase)a or patients with baseline NT-proBNP X650 ng/l) or NYHA class cTn progression (X33% increase) or Ejection fraction response (X2 class decrease in subjects with baseline NYHA progression (X10% decrease) class 3 or 4) Kidney 50% decrease (at least 0.5 g/day) of 24-h urine protein (urine 50% increase (at least 1 g/day) of 24-h urine protein to 41g/ protein must be 40.5 g/day pretreatment). Creatinine and day or 25% worsening of serum creatinine or creatinine creatinine clearance must not worsen by 25% over baseline clearance Liver 50% decrease in abnormal alkaline phosphatase value 50% increase of alkaline phosphatase above the lowest value Decrease in liver size radiographically at least 2 cm Peripheral Improvement in electromyogram nerve conduction velocity Progressive neuropathy by electromyography or nerve nervous system (rare) conduction velocity Abbreviations: NT-proBNP, N-terminal prohormone of brain natriuretic peptide; cTn, cardiac troponin; NYHA, New York Heart Association. aPatients with progressively worsening renal function cannot be scored for NT-proBNP progression.

Table 3. Hematologic response and progression criteria

Response category Criteria

Complete Normalization of the free light chain levels and ratio, negative serum and urine immunoﬁxation Very good partial Reduction in the dFLC to o40 mg/l Partial A greater than 50% reduction in the dFLC No response Less than a PR Progression From CR, any detectable monoclonal protein or abnormal free light chain ratio (light chain must double) From PR, 50% increase in serum M protein to 40.5 g/dl or 50% increase in urine M protein to 4200 mg/day (a visible peak must be present) Free light chain increase of 50% to 4100 mg/l Abbreviations: CR, complete response; dFLC, difference between iFLC and uninvolved FLC; FLC, free light chain; PR, partial response.

Leukemia (2012) 2317 – 2325 & 2012 Macmillan Publishers Limited Clinical research for AL RL Comenzo et al 2321 Organ responses Such assessments are clinically and temporally complex and may Organ disease that is considered to be quantifiable for response challenge the judgment of even the most experienced research includes cardiac disease, renal disease with proteinuria, and teams. Similar concerns apply to distinguishing progression of hepatic disease (Table 2).34,35 Amyloid cardiomyopathy leads to a organ disease from adverse events linked to therapy. concentric increase in ventricular wall thickness; however, change In clinical trials, reporting of hematologic and organ response in mean wall thickness measured by echocardiogram has not yet measures, including cardiac biomarkers, 24-h proteinuria, alkaline been shown to be a useful clinical end point. Worsening left phosphatase, and orthostatic vital signs should be performed at ventricular ejection fraction, while a harbinger of poor outcome, is specified regular intervals during therapy, usually with each cycle. not useful either. Other echocardiographic and cardiac magnetic The complex pathophysiology of AL argues for more innovative resonance imaging approaches are being evaluated but are not and rapid assessments of treatment efficacy to improve patient ready to be incorporated into response assessment. The cardiac outcomes, particularly in the design of phase II trials. Baseline and biomarkers NT-proBNP and troponin T and I have been used for end-of-study scoring that takes into account QOL and perfor- staging and response assessment. Their use has been validated mance status may be particularly useful. in patients treated with conventional23,36–38 and high-dose A further challenge to assessing outcomes in clinical trials for AL chemotherapy.36,39 is the complexity of analyzing adverse events in patients with In the 2010 consensus analyses, biomarker criteria for clinical underlying organ dysfunction. Adverse events in AL clinical trials cardiac response and progression after initial therapy have been must be reported and graded according to standard criteria validated in newly diagnosed patients as shown in Figure 2. This such as those developed by the NCI. Attribution to treatment approach is a major achievement in the scoring of cardiac or to disease relies upon an in-depth understanding of both responses, considering that these biomarkers are easily available manifestations of amyloidosis in general and in the specific in all clinical chemistry laboratories and that they are well patient. Clinical investigators should seek to identify and under- stand novel toxicities that may occur in patients with amyloid standardized worldwide. The occurrence of a biomarker response organ dysfunction. Such a systematic prospective approach is the is clearly associated with improved survival. An appreciation of clearest way to minimize the confounding effects of amyloid- factors that potentially affect biomarker levels need to be kept in related organ disease on the assessment of treatment-related mind, as troponin and NT-proBNP levels can be altered by renal effects. insufficiency or by measures that influence heart failure indepen- Recommendations: dent of the state of AL disease.23 NT-proBNP can also become elevated in patients treated with immunomodulatory agents (1) It is important to remember that the consensus hematologic independent of other laboratory values and may signal worsening and organ response criteria apply to newly diagnosed heart failure.40 patients. Nevertheless, use of the response criteria for While metrics for other organ responses are in use, they have hematologic, cardiac and renal disease is reasonable in not been validated to the degree that cardiac responses have constructing end points for clinical trials of all phases in all been (Table 2). With respect to renal response, proteinuria study populations. (preponderant albuminuria) in a 24-h urine collection is a reliable (2) The criteria for renal response, although not yet adequately measure as long as renal function is stable. Renal responses can validated with respect to organ progression (that is, onset of lag 12–24 months behind hematologic responses or, like cardiac end-stage renal disease), QOL or survival, are easily imple- responses, can occur incrementally during the course of therapy. mented and practical; moreover, associations between sig- Responses of hepatic disease are assessed according to alkaline nificant reductions in proteinuria, increased serum albumin phosphatase (a marker of cholestasis) and liver size. However, levels and improved QOL and performance status have been hepatic markers may be influenced by diastolic heart dysfunction. widely observed by many investigators in patients effectively There are no validated quantitative measures for peripheral treated.44 sensorimotor or autonomic neuropathy or soft tissue or endocrine (3) Baseline grading of patient symptoms and consensus defini- involvement. However, assessment of QOL and performance tions of progression of organ disease should be incorporated status are relevant quantifiable measures of clinical status and into clinical trials, and distinctions between adverse events indirectly of overall physiologic response to treatment. It is and progression of disease should be based on a compre- reasonable to expect statistical concordance between changes in hensive evaluation of the individual case by the center organ disease, QOL and performance status. For QOL, the SF36 has investigator, consensus of investigators and, if appropriate, been used in AL and has been shown to reflect improvement with 41 the Data Safety Monitoring Board. effective treatment. (4) Persistent organ dysfunction in patients with salutatory Single-center case series depict the direct association between 42 hematologic responses may be related to some aspect of hematologic response and organ responses. The parallel the therapy, particularly if there is evidence for such reduction of FLC and cardiac biomarkers is associated with 23,43 associations in other patient populations. Absent such extended survival. As a general rule, the deeper the hemato- evidence, the basis for the adverse event may be attributed logic response, the greater the likelihood of organ response. to underlying AL organ disease. In phase I trials of novel Occasionally, the achievement of a PR translates into a significant agents developed specifically for amyloidosis or AL, the report organ response, suggesting that the toxicity and fibrillar potential of the patient and the evaluations of the center investigator, of the iFLC was dependent on a threshold concentration. The sponsor and regulatory agencies will determine the likelihood reverse has also been observed; that is, occasionally, patients of an association with the novel agent. achieving normalization of the FLC continue to experience organ damage as can happen in patients with baseline low-level iFLC and renal involvement. In such cases, it is often unclear whether the worsening renal function is due to a highly toxic iFLC, the STUDY POPULATIONS impact of chronic proteinuria on tubular function, or both. Therapies for AL have historically been aimed at eliminating the When there is dysynchrony in responses, for instance a PR clonal plasma cells producing the toxic precursor protein.45 We with worsening organ disease, it likely means that the level define the major study populations as the newly diagnosed of hematologic response is inadequate, or the extent of untreated, those who respond to initial therapy, and the organ disease too profound, for an organ response to occur.20 relapsed/refractory, based on the hematologic parameter of FLC

& 2012 Macmillan Publishers Limited Leukemia (2012) 2317 – 2325 Clinical research for AL RL Comenzo et al 2322 response. Moreover, the presence of cardiac stage III disease by alkylator- and proteasome-inhibitor-based therapy before being biomarkers has become an exclusion criterion for phase III trials considered for phase I trials. Trials of anti-amyloid agents should of initial therapy. This practice effectively creates two newly be limited to those with unresponsive organ disease. diagnosed study populations, those with or without advanced (2) A portfolio of phase I trials for AL for relapsed/refractory cardiac disease. Refractory hematologic disease is absence of patients, available in multiple centers and led by experienced hematologic response (less than a PR) to initial therapy. Lack of investigators, is strongly encouraged. Possible sources of hematologic response increases risk of shortened survival. support include advocacy groups, pharmaceutical companies, Although absence of an organ response would appear to define and state and federal agencies. There are currently no it, refractory organ disease is more difficult to categorize. For standard therapies for relapsed/refractory patients. Therefore, example, patients with cardiac stage II or III disease can have an we strongly suggest that time-to-event measures be included NT-proBNP biomarker response to initial therapy but remain stage and reported as secondary end points in trials to aid in the II or III and continue to be at high risk of sudden death, and design of subsequent studies. patients with proteinuria 420 g/day can have a renal response (3) The clinical end points appropriate for patients with relapsed/ but still have proteinuria of 10 g/day. In both instances, the risks of refractory AL are not well standardized on the phase II level. sudden cardiac death or end-stage renal disease remain salient. Achievement of hematologic CR after initial therapy correlates Refractory organ disease then is defined as persistent significant with superior PFS and OS. Therefore, hematologic response is organ disease causing symptoms despite prior therapy and best a valid end point for phase II trial design, particularly when supportive care. Relapsed disease is progression of hematologic or linked to metrics of clinical and organ response in which the organ disease after a response to initial therapy. Hematologic clinical benefit to patients is well defined. relapse often precedes progression of organ disease. In one series, (4) Consideration must be given to the concept of disease only a quarter of patients without a hematologic CR after SCT progression on phase I and II trials for relapsed/refractory remained stable without organ progression for 5 years.46 patients. Stable hematologic disease is not an innocuous Several phase II clinical trials in relapsed/refractory patients category of response in AL as in myeloma because of the risk have been performed with immunomodulatory agents or the of organ-disease progression. Given the direct link between proteasome inhibitor bortezomib as single agents or in combi- lack of hematologic response, progressive organ disease and nation with alkylating agents and steroids with promising shortened survival, it is not reasonable to continue to treat results.45,47–50 However, the outcomes of these clinical trials are patients on trials of chemotherapies provided they have stable difficult to interpret because of the mix of patients with respect to hematologic disease. Without a hematologic response after disease status, prior initial therapy, extent of organ involvement several cycles, patients should be removed from study or have and different ways of reporting results. For phase III studies in provisions for alternative treatment on study. relapsed/refractory patients, stratification based on degree of organ disease is indicated. The design of such trials remains a challenge because there is no standard therapy for relapsed/ refractory AL, and therefore use of any regimen in the control arm TIME-TO-EVENT END POINTS is arbitrary. There are a number of time-to-event end points that are Newly diagnosed patients who have achieved a PR or better potentially relevant to AL clinical trials (Table 4). The major caveat with initial therapy are considered as responders. In AL, in this regard, however, is that hematologic response is intrinsi- maintenance therapy with dexamethasone and a-interferon for cally linked both to organ response and to survival and, given the a total of 5 years was planned following induction with pulse rarity of AL, hematologic response remains a preferred primary dexamethasone in patients enrolled on the Southwest Oncology end point for phase III trials with the notable exception of trials Group S9628 trial but was tolerated poorly with 63% of patients for patients with advanced cardiac involvement. OS is the most experiencing grade 3 or 4 toxicities.51 Adjuvant therapy with 9 precise and reliable end point for trials in patients with the high months of thalidomide and dexamethasone following risk- mortality rate of advanced AL cardiac involvement, and also for adapted SCT in patients who did not achieve CR resulted in trials testing therapies that may cause side effects associated with hematologic responses in 71% of patients including 36% who progressive organ dysfunction and may not therefore enhance achieved CR at 12 months post SCT.52 In a similar trial, survival. investigators used bortezomib and dexamethasone for six cycles In phase III trials, the utility of OS as the primary end point may following SCT, reporting an overall response rate of 96% with CR be affected by the availability of effective agents as second-line in 65% of patients.53 Novel agents following initial therapy or SCT therapy and by crossover trial designs. If OS is the primary end appear effective for AL, but uniform definitions of ‘consolidation’ point in a phase III trial for newly diagnosed or relapsed/refractory and ‘maintenance’ are needed to design clinical trials and to patients, then those coming off-study on the less effective arm develop standard practice guidelines. We define consolidation for may achieve equivalent survival with novel investigational therapy patients achieving a response to initial therapy as treatment with or with crossover. Although this is currently less of a concern in AL non-cross resistant therapy administered with the goal of than in myeloma, time-to-next-treatment (TNT) or PFS not OS may improving the hematologic response, while maintenance is be useful primary end points for such trials and may better reflect therapy administered over a prolonged time (for example, 12 the activity of the drug or schedule under study. months or more) with the goal of prolonging PFS. Although this argument is cogent, the limitations of TNT or PFS Recommendations: may be particularly problematic in chemotherapy trials for patients with AL. Those with a PR, for example, can have progres- (1) We recommend that clinical trials be conducted for the sion of organ disease and may need additional treatment in spite following specific study populations in independent trials or of a PR, and the hiatus required to make that clinical determina- as subgroups in trials: newly diagnosed untreated without tion might be short but would fit TNT. With respect to PFS, advanced cardiac involvement; newly diagnosed untreated patients with multiple organs involved who achieve hemato- with advanced cardiac involvement; relapsed/refractory logic and single organ responses but progression of other organ patients; and responders to initial therapy. Phase I trials at dysfunction would have a short PFS. this time should be limited to patients with relapsed/refractory In chemotherapy trials then, assessing PFS should logically disease for whom no other standard therapy exists. In the encompass assessment of both hematologic and organ diseases. current era, almost all patients will have been treated with In contrast, in trials of agents aimed at promoting resorption of

Leukemia (2012) 2317 – 2325 & 2012 Macmillan Publishers Limited Clinical research for AL RL Comenzo et al 2323 Table 4. Time-to-event end points relevant to clinical trials for patients with light-chain amyloidosis (AL)s

End point Deﬁnition Comment

Progression-free Time from start of treatment to Relevant to both chemotherapy and anti-amyloid therapies; for the former likely must survival (PFS) disease progression or death include both hematologic and organ-related parameters, and for the latter needs to be applied in an organ-specific manner Time-to next Time from end of last treatment to Difficult to implement in AL because of the interdependence of hematologic and organ treatment (TNT) start of the next disease and the lack of standardized treatments Overall survival Time from start of treatment to Appropriate primary end point for phase III trials studying treatments in patients with (OS) death advanced AL cardiac disease; needed as a secondary end point in phase II trials with response as primary end point amyloid deposits, PFS could be an important end point. Although CONCLUSIONS it is unlikely that a single anti-amyloid agent would be used in We have outlined a forward-looking framework for clinical research patients with a persistent monoclonal iFLC component, it is and drug development in systemic AL. In Europe, where national possible that either PFS or OS could be the primary end point on centers and networks dedicated to clonal plasma-cell diseases exist, the randomized phase II or phase III level. the past few years have seen the emergence of a collaborative effort Although TNT is a more liberal time-to-event end point, one in phase II and III clinical trial development in AL, aided by pharma- possibly suited for phase III AL trials in relapsed/refractory patients, ceutical company involvement. In the United States, the cooperative use of the TNT end point depends upon the judgment of the groups have led trials in AL over the years but the time has come investigators and also assumes that a menu of therapies or trials for them to collaborate directly and fully in trial development and (‘next therapies’) exist when in fact they do not. The era of phase I adoption of study population and end point criteria. and I/II multicenter trials in AL has only just begun. Patients who Single-center phase I trials may have a place in drug have hematologic or organ progression, or a PR with stable but development but, given the rarity of AL and the burden that clinically morbid organ disease, may be offered additional empiric travel places on sick patients, multicenter networks for the therapy depending on the experience and practice of their conduct of phase I trials are clearly needed. Such networks would physician. Of note, the detection of persistent amyloid deposits provide opportunities for drug development among experienced in abdominal fat, bone marrow or involved organ is not an clinical groups within standardized formats, making collaboration indication for further therapy since amyloid deposits can persist for with interested pharmaceutical companies easier. The future years after functional recovery of the target organs. success of clinical trial and drug development for AL requires Recommendations: collaboration among dedicated investigators in centers of excellence, along with conscientious and motivated referring (1) For phase III trials employing chemotherapeutic agents for physicians who seek clinical trials for their patients with AL and newly diagnosed untreated patients without advanced cardiac who support their patients’ participation in them. involvement, hematologic response is a more appropriate Employing novel agents approved for related diseases outside of primary end point than OS. We note that the exigencies of the context of clinical trials will slow the process of identifying sample size, accrual time and standards of regulatory bodies optimal dosing, schedule, and combinations for this unusual patient with respect to new drug applications are factors that may population. The potential for more favorable outcomes with influence the use of one or both of these as primary end combinations of chemo- and immuno-therapies makes collaboration points. In phase III trials, patients must be stratified based on and patient willingness to participate imperative to achieve the goal the degree of cardiac involvement to balance the arms. of cure. We hope that the approach we outline provides a timely and (2) With respect to newly diagnosed patients with advanced effectiveplatformthatprovestobeofbenefittopatients. cardiac involvement, new approaches that may prolong survival for these patients could be tested straightforwardly in phase III trials with OS as the primary end point. CONFLICT OF INTEREST (3) Multicenter phase II trials are encouraged and we recommend The authors declare no conflict of interest. strongly that time-to-event end points be routinely included as secondary end points in such studies to provide information for phase III trial design. ACKNOWLEDGEMENTS (4) Both consolidation and maintenance should be explored in We thank the supporters of the Amyloidosis Foundation and the Foundation’s Board multicenter clinical trials in responders to initial therapy. The of Directors whose continued efforts and involvement made this first roundtable held concepts of consolidation and maintenance can apply to in Boston in late 2010 a reality. We also thank S Frieda Pearce, PhD, for editing chemotherapeutic agents and hematologic disease and also to assistance. anti-amyloid agents and organ disease. Phase II trials designed to measure the efficacy of consolidation regimens may employ improvement in hematologic response as their primary end REFERENCES point but should also report organ responses and OS, while 1 Merlini G, Palladini G.. Amyloidosis: is a cure possible? Ann Oncol 2008; 19(Suppl 4): maintenance trials can employ PFS as their primary end point. iv63–iv66. 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