Bortezomib retreatment is effective in relapsed multiple myeloma patients - real-life clinical practice data.

Nowadays, bortezomib, a proteasome inhibitor, is widely used in treatment of newly diagnosed or relapsed multiple myeloma. The aim of this study was to analyze efficiency of bortezomib retreatment in patients with relapsed or refractory multiple myeloma. From 2004 to 2016, 283 patients were retrospectively evaluated at all hematological centers in the Czech Republic. Bortezomib was administered at the standard dosing and in combined therapy with corticosteroids, chemotherapy or thalidomide. Before bortezomib retreatment, 61% of patients received previous lenalidomide treatment, 40.6% autologous transplantation, and median number of prior lines of therapy was three. In total, 21% of patients were refractory to the first bortezomib treatment. In bortezomib retreatment, overall response rate was 34.5%, median progression-free survival was 7.8 months (95% CI: 6.7-8.9), median duration of response was 10.5 months (95% CI: 8.0-13.0) and median overall survival was 20.3 months (95% CI: 17.9-22.7). Grade 3-4 adverse events included thrombocytopenia, neutropenia, anemia and infection. Neuropathy grade 2 or higher occurred in 19.4% of patients. We conclude that bortezomib retreatment is an effective and safe therapeutic alternative for relapsed or refractory multiple myeloma patients.

Methodology and results of real-world cost-effectiveness of carfilzomib in combination with lenalidomide and dexamethasone in relapsed multiple myeloma using registry data.

OBJECTIVE: To predict the real-world (RW) cost-effectiveness of carfilzomib in combination with lenalidomide and dexamethasone (KRd) versus lenalidomide and dexamethasone (Rd) in relapsed multiple myeloma (MM) patients after one to three prior therapies. METHODS: A partitioned survival model that included three health states (progression-free, progressed disease and death) was built. Progression-free survival (PFS), overall survival (OS) and time to discontinuation (TTD) data for the Rd arm were derived using the Registry of Monoclonal Gammopathies in the Czech Republic; the relative treatment effects of KRd versus Rd were estimated from the phase 3, randomised, ASPIRE trial, and were used to predict PFS, OS and TTD for KRd. The model was developed from the payer perspective and included drug costs, administration costs, monitoring costs, palliative care costs and adverse-event related costs collected from Czech sources. RESULTS: The base case incremental cost effectiveness ratio for KRd compared with Rd was €73,156 per quality-adjusted life year (QALY) gained. Patients on KRd incurred costs of €117,534 over their lifetime compared with €53,165 for patients on Rd. The QALYs gained were 2.63 and 1.75 for patients on KRd and Rd, respectively. CONCLUSIONS: Combining the strengths of randomised controlled trials and observational databases in cost-effectiveness models can generate policy-relevant results to allow well-informed decision-making. The current model showed that KRd is likely to be cost-effective versus Rd in the RW and, therefore, the reimbursement of KRd represents an efficient allocation of resources within the healthcare system.

Lenalidomide and dexamethasone in treatment of patients with relapsed and refractory multiple myeloma - analysis of data from the Czech Myeloma Group Registry of Monoclonal Gammopathies.

Lenalidomide (LEN) is an immunomodulator with clinical activity against myeloma cells. Based on the pivotal phase 3 trials MM-009 and MM010, the combination of lenalidomide and dexamethasone(DEX) was approved for patients with multiple myeloma who received at least one prior therapy. Here, we evaluated LEN/DEX therapy in unselected population and subsequently in selected sub-groups of patients with relapsed/refractory multiple myeloma followed in the Registry of Monoclonal Gammopathies of the Czech Myeloma Group. Altogether 858 patients were treated with LEN/DEX in the Czech Republic and Slovakia until end of 2017. The analyzed sub-groups were defined as patients with high risk cytogenetic aberrations and patients with relapsed and refractory MM. The overall response rate (ORR; partial remission or better response, PR) in the whole group of patients was 46.3% for all lines of therapy, 26.4% for high-risk group and 32.1% for relapsed and refractory group. Medians of overall survival (OS) in the same cohorts were as follows: 25.6, 15.7 and 18.5 months, progression free survival (PFS) was: 11.2, 6.4 and 9.0 months respectively. The most common adverse events were hematologic and infectious. In conclusion we found that our results correlated with those found in other studies in terms of response rates, survival measures, and also of treatment toxicity.

Simplified novel prognostic score for real-life older adults with multiple myeloma-registry-based analysis.

The main goal was to find a simple prognostic to evaluate overall survival of patients older than 65 years of age with myeloma. Retrospective registry-based analysis from the Registry of Monoclonal Gammopathies was conducted. Patients over 65 years with symptomatic myeloma were included. The four major parameters with impact on survival were identified: male gender, age > 75, creatinine > 152 µmol/L, and ECOG performance status 2-4. The patients were scored as good (0 points), intermediate good (1 point), intermediate poor (2 points), poor (3-4 points). Patients (1410 MM) were included. Median OS (months) was 65.7 (95% CI 49.8-81.7) for good, 51.0 (44.1-57.8) for intermediate good, 32.2 (26.2-38.2) for intermediate poor, and 18.9 (15.1-22.7) for poor. The differences in OS were statistically significant (p < 0.0001). Good score was used as reference for hazard ratios, which for each other score were 1.43 (1.09-1.84) for intermediate good, 2.58 (2.00-3.33) for intermediate poor, and 3.88 (2.94-5.10) for poor. Time to progression showed medians (months) 20.5 (17.4-62.4) for good, 19.3 (17.0-21.7) for intermediate good, 19.6 (16.2-23.0) for intermediate poor, and 13.0 (10.8-15.2) for poor. The suggested scoring system provides readily available information about the prognosis of MM patients above 65 years.

Whole Exome Sequencing of Aberrant Plasma Cells in a Patient with Multiple Myeloma Minimal Residual Disease.

Multiple myeloma is a plasma cell dyscrasia. It is the second most common hematological malignancy which is characterized by proliferation of clonal plasma cells producing harmful monoclonal immunoglobulin. Despite treatment modalities greatly evolved during the last decade, small amount of aberrant residual cells reside in patients after therapy and can cause relapse of the disease. Characterization of the residual, resistant clones can help to reveal important therapeutic targets for application of effective and precious treatment. We use CD38, CD45, CD56 and CD19 sorted aberrant plasma cells to perform next generation sequencing of their exome. Among the 213 genes in which at least one variant was present, the most interesting was found gene NRAS, one of the most often mutated gene in multiple myeloma, and homologs of 88 gene panel previously used for multiple myeloma sequencing among which was a gene previously identified as gene meaningful in bortezomib resistance. Nevertheless, the results of next generation exome sequencing need to be interpreted with caution, since they rely on bioinformatical analysis, which is still being optimized. The results of next generation sequencing will also have to be confirmed by Sanger sequencing. Final results supported by larger cohort of patients will be published soon.Key words: multiple myeloma - minimal residual disease - exome - next generation sequencing.

Epidemiology of Multiple Myeloma in the Czech Republic.

BACKGROUND: Multiple myeloma (MM) is a cancer of plasma cells with an incidence of 4.8 cases per 100,000 population in the Czech Republic in 2014; the burden of MM in the Czech Republic is moderate when compared to other European countries. This work brings the latest information on MM epidemiology in the Czech population. MATERIAL AND METHODS: The Czech National Cancer Registry is the basic source of data for the population-based evaluation of MM epidemiology. This database also makes it possible to assess patient survival and to predict probable short-term as well as long-term trends in the treatment burden of the entire population. RESULTS: According to the latest Czech National Cancer Registry data, there were 504 new cases of MM and 376 deaths from MM in 2014. Since 2004, there has been a 26.9% increase in MM incidence and an 8.3% increase in MM mortality. In 2014, there were 1,982 persons living with MM or a history of MM, corresponding to a 74.4% increase when compared to MM prevalence in 2004. The 5-year survival of patients treated in the period 2010-2014 was nearly 40%. CONCLUSION: The available data make it possible to analyse long-term trends in MM epidemiology and to predict the future treatment burden as well as treatment results.Key words: multiple myeloma - epidemiology - Czech National Cancer Registry - Registry of Monoclonal Gammopathies - Czech Republic.

Czech Registry of Monoclonal Gammopathies - Technical Solution, Data Collection and Visualisation.

BACKGROUND: The Registry of Monoclonal Gammopathies (RMG) was established by the Czech Myeloma Group in 2007. RMG is a registry designed for the collection of clinical data concerning diagnosis, treatment, treatment results and survival of patients with monoclonal gammopathies. Data on patients with monoclonal gammopathy of undetermined significance (MGUS), Waldenström macroglobulinaemia (WM), multiple myeloma (MM) or primary AL ("amyloid light-chain") amyloidosis are collected in the registry. DATA: Nineteen Czech centres and four Slovak centres currently contribute to the registry. The registry currently contains records on more than 5,000 patients with MM, almost 3,000 patients with MGUS, 170 patients with WM and 26 patients with primary AL amyloidosis, i.e. more than 8,000 records on patients with monoclonal gammopathies altogether. RESULTS: This paper describes technology employed for the collection, storage and subsequent online visualisation of data. The CLADE-IS platform is introduced as a new system for the collection and storage of data from the registry. The form structure and functions of the new system are described for all diagnoses in general; these functions facilitate data entry to the registry and minimise the error rate in data. Publicly available online visualisations of data on patients with MGUS, WM, MM or primary AL amyloidosis from all Czech or Slovak centres are introduced, together with authenticated visualisations of data on patients with MM from selected centres. CONCLUSION: The RMG represents a data basis that makes it possible to monitor the disease course in patients with monoclonal gammopathies on the population level.Key words: Registry of Monoclonal Gammopathies - RMG - registries - monoclonal gammopathies - CLADE-IS - data visualisation - database.

Asymptomatic and Treatment-requiring Multiple Myeloma - Data from the Czech Registry of Monoclonal Gammopathies.

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) and smouldering multiple myeloma (SMM) are premalignant stages of multiple myeloma (MM). MM is a malignancy of plasma cells, which is associated with a median overall survival of 5 to 7 years. MM accounts for approximately 10% of hematological malignancies. PATIENTS AND METHODS: Descriptive analysis of data from 19 Czech centres collected in the Registry of Monoclonal Gammopathies (RMG) was performed. RESULTS: Over the last 10 years of prospective collection of data, together with retrospectively recorded data on patients diagnosed before the registry establishment, data on 7,467 patients with either asymptomatic or symptomatic form of MM have been gathered. Validation criteria for the analysis were met by 2,506 MGUS patients, 400 SMM patients and 4,738 MM patients. The median duration of follow-up was 4.3 years in MGUS patients and 2.4 years in SMM patients. The overall risk of progression from MGUS to malignancy was 1.7% per year. The risk of progression from SMM to MM was highest in the 1st years after diagnosis: overall, this risk was 16.6% per year. The median duration of follow-up was 2.8 years in MM patients. The median overall survival from the diagnosis was 5.7 years. The median OS from treatment initiation/progression-free survival decreased from 60.5/21.0 months in the 1st line therapy to 34.3/12.4 months in the 2nd line therapy, 22.6/8.9 months in the 3rd line therapy and 13.8/5.8 months in the 4th or higher line therapies. Thanks to the availability of novel drugs for MM treatment in the Czech Republic, treatment strategies have changed dramatically over the last decade. CONCLUSION: RMG is a registry designated for the collection of data on diagnosis, treatment, treatment results and survival of patients with monoclonal gammopathies in the long-term follow-up. RMG is a valuable source of data from real clinical practice.Key words: registries - monoclonal gammopathy of undetermined significance - smouldering multiple myeloma - multiple myeloma - progression - treatment - survival.

A randomized phase III study of carfilzomib vs low-dose corticosteroids with optional cyclophosphamide in relapsed and refractory multiple myeloma (FOCUS).

This randomized, phase III, open-label, multicenter study compared carfilzomib monotherapy against low-dose corticosteroids and optional cyclophosphamide in relapsed and refractory multiple myeloma (RRMM). Relapsed and refractory multiple myeloma patients were randomized (1:1) to receive carfilzomib (10-min intravenous infusion; 20 mg/m2 on days 1 and 2 of cycle 1; 27 mg/m2 thereafter) or a control regimen of low-dose corticosteroids (84 mg of dexamethasone or equivalent corticosteroid) with optional cyclophosphamide (1400 mg) for 28-day cycles. The primary endpoint was overall survival (OS). Three-hundred and fifteen patients were randomized to carfilzomib (n=157) or control (n=158). Both groups had a median of five prior regimens. In the control group, 95% of patients received cyclophosphamide. Median OS was 10.2 (95% confidence interval (CI) 8.4-14.4) vs 10.0 months (95% CI 7.7-12.0) with carfilzomib vs control (hazard ratio=0.975; 95% CI 0.760-1.249; P=0.4172). Progression-free survival was similar between groups; overall response rate was higher with carfilzomib (19.1 vs 11.4%). The most common grade ⩾3 adverse events were anemia (25.5 vs 30.7%), thrombocytopenia (24.2 vs 22.2%) and neutropenia (7.6 vs 12.4%) with carfilzomib vs control. Median OS for single-agent carfilzomib was similar to that for an active doublet control regimen in heavily pretreated RRMM patients.

Immunoparesis in MGUS - Relationship of uninvolved immunoglobulin pair suppression and polyclonal immunoglobuline levels to MGUS risk categories.

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic, potentially malignant condition. It has been established that annually approximately 1-2% of MGUS cases transforms into one of the malignant forms of monoclonal gammopathies. Progression risk factors include the quantity and type of M-protein, and namely the ratio of free light immunoglobulin chains (FLC). These factors, enable purposeful stratification of MGUS individuals. Some authors consider suppression of polyclonal immunoglobulin levels to be another progression factor. The aim of the study was to compare polyclonal immunoglobulin (PIg) levels with uninvolved heavy/light chain pair (HLC) levels in order to verify the degree of immunoparesis depending on MGUS risk category (0-3). The analyzed set consisted of 159 serum samples from MGUS patients (102 IgG, 57 IgA), who were stratified into 4 risk groups (0 - low, 1 - low-intermediate, 2 - high-intermediate and 3 - high risk of transformation). The results of analysis showed that with increasing degree of MGUS increases risk of immune paresis defined by decreasing levels of polyclonal immunoglobulins, ie. IgA and IgM in the case of IgG MGUS, respectively, IgG and IgM in case of IgA MGUS. Significant differences were also found when analyzing the levels of uninvolved HLC pairs IgG kappa (resp. IgG lambda) in IgG lambda (IgG kappa) dominant secretion. In the case of MGUS with IgA isotype, the results were similar. Discovery of the connection between the degree of immunosuppression and the level of MGUS risk contributes to our understanding of the relationship between biology, development and potential malignant transformation of MGUS. It is apparent that uninvolved HLC pair assay enables more reliable identification of at-risk MGUS patients than a simple quantitative assay for polyclonal immunoglobulins alone.

Successful radiotherapy treatment of lacrimal gland infiltration in patient with Sjögren΄s syndrome.

OBJECTIVE: To present a single case report on successful radiotherapy treatment of lacrimal gland infiltration in patient with Sjögren΄s syndrome. BACKGROUND: Radiotherapy is occasionally used for the treatment of benign disorders. There is no report on use of radiotherapy for local treatment of the Sjögren΄s syndrome in the literature. METHODS: Female patient with lacrimal gland involvement as a part of Sjögren΄s syndrome with diplopia and visus deterioration was treated by radiotherapy with eye shielding. RESULTS: Regression of the infiltration with full restoration of visus and minimal acute radiation reaction was achieved. CONCLUSION: A case report of successful use of local radiotherapy in the treatment of lacrimal gland affected by Sjögren΄s syndrome is presented (Fig. 3, Ref. 6). Full Text in PDF www.elis.sk.

Monoclonal gammopathy of undeterminated significance: introduction and current clinical issues.

Monoclonal gammopathy of undetermined significance (MGUS) is a precancerosis comprising two different kinds of cancer: lymphoid/lymphoplasmocytoid MGUS and plasma cell MGUS that represents about 85% of all MGUS cases. This type of MGUS has low but persistent tendency to transform to malignant disease, mainly multiple myeloma (MM), with frequency of about 1% per year. Using known risk stratification models based on clinical parameters, it is possible to identify patients' groups with average rates of progression as low as 0.26% and as high as 12% per year. However, due to the lack of clear genetic and/or phenotypic markers distinguishing MGUS from MM, we are not able to predict if and when MGUS will progress to MM in individual patients. There are partially overlapping molecular pathogenic events shared by MGUS and MM. Better understanding of pathogenesis of MGUS and MM using molecular-genetic approaches will help disclose the mechanisms of myeloma genesis; it can be also useful for identification of novel molecular targets. The ultimate goal for the near future is to develop better markers for definition of high-risk MGUS patients who will be candidates for early treatment intervention.

Low molecular weight heparins for thromboprophylaxis during induction chemotherapy in patients with multiple myeloma.

BACKGROUNDS: Patients with multiple myeloma have a high risk of venous thromboembolism (VTE), especially during the induction chemotherapy. The aim of our observational study was to determine the impact of prophylaxis with low molecular weight heparin (LMWH) on the incidence of thromboembolic complications. PATIENTS AND METHODS: We analyzed the incidence of thromboembolic events in 258 patients treated with induction chemotherapy containing vincristin, doxorubicin or idarubicin, and dexamethasone, followed by stimulation chemotherapy with cyclophosphamide and G-CSF, and high-dose chemotherapy with melphalan. Two groups of these patients were compared based on the practice of thromboprophylaxis. Patients in the first group (Control, n = 140) were either not treated or treated with a short duration of anticoagulation therapy while the patients in the second group (Prophylactic, n = 118) underwent standard prophylaxis with LMWH throughout the entire period of induction chemotherapy. A total of 102 patients were selected for a close monitoring of the prophylactic effect of different LMWH doses and to be compared to patients without treatment. RESULTS: Standard prophylaxis with LMWH significantly (p < 0.007) lowered a risk of VTE when compared to patients without such prophylaxis (3.4% versus 12.9%, respectively). Furthermore, analysis of the subgroup of 102 patients revealed that higher LMWH doses (> 70 IU/kg per day) achieved full prophylaxis in 28 patients while lower doses were less effective leading to DVT in 3 (7.7%) out of 39 patients. In contrast, VTE was diagnosed in 5 (14.3%) out of 35 patients without any LMWH prophylaxis. CONCLUSION: Prophylaxis with LMWH leads to a significant reduction of the risk of thromboembolic complications during the induction chemotherapy in patients suffering from MM. The prophylactic effect of LMWH is dose-dependent.

[The role of procalcitonin in the differential diagnosis of fever in patiens with multiple myeloma]. / Vyuzití prokalcitoninu v diferenciální diagnostice febrilií u pacientu s mnohocetným myelomem.

Fever and elevated C-reactive protein are frequently found in hematooncological patients. It is sometimes difficult to distinguish between infectious fever and drug-related or tumour-associated fever. Tumour-related fever is not very common in multiple myeloma (unlike malignant lymphomas). C-reactive protein (CRP) is usually elevated simultaneously with fever and so it cannot be used in differential diagnosis of febrile states. There is another marker that provides information about the origins of the fever--rocalcitonin. We present cases of three patients that illustrate the significance of procalcitonin in patients with multiple myeloma.

The problems of proteinuria measurement in urine with presence of Bence Jones protein.

OBJECTIVES: Protein concentration measurement in the urine can be problematic in the presence of Bence Jones protein. We have carried out an external quality control assessment with the participation of 79 clinical biochemistry laboratories from the Czech Republic and Slovakia. DESIGN AND METHODS: The laboratories received a reference urine sample obtained from a patient with multiple myeloma and lambda free light chain proteinuria and were asked to type the paraprotein using immunofixation and to measure total urinary protein using their established method, most commonly turbidimetry, pyrogallol red assay, and biuret assay. RESULTS: There was a very wide inter-laboratory variability in the protein concentration readouts with up to three-fold difference in some cases. High-resolution two-dimensional electrophoresis and linear mass spectrometry showed that a high proportion of the urinary paraprotein was composed of lambda light chain fragments with molecular weight of 12kDa. CONCLUSIONS: Our results highlight the challenges of reliable and reproducible measurement of urinary protein concentration in the presence of Bence Jones protein.

[Lenalidomide in the treatment of multiple myeloma]. / Lenalidomid v lébe mnohocetného myelomu.

We present the case of a 58-year old patient with relapsed multiple myeloma, in which lenalidomide was used in combination with dexamethasone after the failure of previous treatment modalities. The progression of the myeloma was clinically manifested by painful swelling of the patient's left arm caused by an extensive osteolytic lesion of the bone. After one month of therapy with lenalidomide and dexamethasone, a significant decrease in the paraprotein level was detected. Later, the clinical finding on the left arm was normalized too and concurrently the X-ray image shows the production of new bone.

Diagnosis and surgical therapy of plasma cell neoplasia of the spine.

Presented is a retrospective analysis of 27 patients with plasma cell neoplasms of the spine treated by surgery. Multiple myeloma was confirmed in 22 (81%) and solitary plasmacytoma in 5 patients (19%), assessed at the time of surgery. Nineteen patients (70%) with the preliminary diagnosis of malignancy of unknown etiology were admitted for surgery. In 23 patients (85%) the essential symptom was back pain, which preceded surgery by an average of 4 months. Thirteen patients (48%) were bedridden due to tumor spinal cord compression, on average for 7 days before undergoing surgery. Only 5 out of 13 bedridden patients (38%) regained the ability to walk after surgery and 8 patients (62%) remained bedridden despite successful surgical decompression of the spinal cord. The difference of survival of the patients between bedridden and able to walk prior to surgery was statistically significant (Cox's F-Test = 0.005). Key words: plasma cell neoplasia, spinal cord compression, late diagnosis, outcome.

[Monoclonal gammopathies of undetermined significance]. / Monoklonálne gamapatie nejasného významu.

Monoclonal gammopathy of undetermined significance (MGUS) is the most common type of monoclonal gammopathies. Genetic changes, various cytokines and bone marrow angiogenesis play an important role in the pathogenesis. As far as the malignant transformation of MGUS is concerned, size and type of the serum M-protein, serum kappa and lambda free light chain ratio and number of plasma cells in peripheral blood seem to play a predictive role. A new possible risk-stratification model predicting progression of MGUS to multiple myeloma or other related disorders was presented in 2006. The model takes three parametres in consideration, type and initial size of the serum M-protein and serum kappa and lambda ratio. Patients are divided into four risk groups with different risk of progression, from 5% at 20 years in low risk group to 58% in high risk group. The interval from MGUS diagnosis to the evolution of multiple myeloma or other related malignancies ranges from 1 to 30 years. Nevertheless, the risk of progression persists even after more than 30 years after MGUS diagnosis.

[Myopathy and mixed hyperlipoproteinemia as the first symptom of systemic AL-amyloidosis]. / Myopatie a smísená hyperlipoproteinemie jako první projev systémové AL-amyloidózy.

Systemic AL-amyloidosis is a disorder brought about by the over-production and deposition of fragments of light immunoglobulin chains in tissues, the consequence of which is their functional impairment. The most often affected are the kidneys, the heart, the gastro-intestinal tract and the nervous system. We describe the case of a 57-year-old patient in whom a rare disorder of the striated muscle (am yloid myopathy) was present, as the first clinical indication of systemic AL-amyloidosis. The main symptoms were muscle weakness and an increase in laboratory signs of muscle lesion. The patient was monitored for several years and treated with a diagnosis of primary idiopathic polymyositis (the likely diagnosis according to the diagnostic criteria of Bohan and Peter). Only after some years did hepatomegaly appear with elevated liver transaminases and a diagnosis of systemic AL-amyloidosis was established on the basis of a liver biopsy. By additional staining of striated muscle preparations with a dye for amyloid (in accordance with Maldyk) amyloid myopathy was confirmed. In addition to muscle affection, mixed hyperlipoproteinemia was present from the beginning. This was probably the first indication ofamyloidosis. The case description points out the justified inclusion of systemic AL-amyloidosis in differential diagnosis of muscle weakness and signs of muscle lesion. Amyloidosis must be considered if in addition to myopathy there is also present a problem with any organ which can typically be affected by amyloidosis.

The Czech National External Quality Assessment of monoclonal immunoglobulin in the period of 1996 - 2005.

The aim of the presented study was to evaluate the results of SEKK "Gammopathy" (GP) control cycle (Czech National External Quality Assessment) that assessed the success rate of monoclonal immunoglobulin determination by clinical laboratories for the 1996 - 2005 period. The study summarizes the results of 20 "Gammopathy" control cycles during the ten-year period. Control cycles were repeated every 6 months. Patients who provided samples for individual SEKK "Gammopathy" control cycles were selected during routine diagnostic process in the University Hospital Hradec Kralove. Correct paraprotein typing in both A and B control samples (plasma, serum or urine) is required prior to certification. Assessment of paraprotein concentration is optional. The number of participating laboratories was gradually increasing from 26 in 1996 to 79 in 2005 (including 6 Slovak laboratories). The majority of laboratories used immunofixation electrophoresis as the method of paraprotein typing. In 2005, only one laboratory was still using immunoelectrophoresis. Typing was successful in approximately 70% of cases during the first 3 cycles and the success rate gradually increased to almost 96% by 2005. The only exception was GP 1/02 cycle with a sample of relatively rare IgD-lambda paraprotein and the success rate of 38% only. A sample of plasma without paraprotein was distributed 4 times. Several laboratories falsely identified fibrinogen as paraprotein each time. Results of "Gammopathy" control cycle for the past 10 years confirmed the value and legitimacy of this control cycle in the system of external quality control of SEKK laboratories.