Second malignancies and Richter's syndrome in patients with chronic lymphocytic leukaemia treated with cladribine

Additional malignancies shorten overall survival in chronic lymphocytic leukemia irrespective of chromosomal aberrations: A retrospective cohort study

The aim of this study was to determine the incidence of other malignancies (OMs) in patients with chronic lymphocytic leukemia (CLL) and to identify parameters associated with the occurrence of OMs in addition to CLL. This retrospective cohort study was conducted by examining the records of CLL patients who applied to a tertiary hospital between January 2013 and December 2021. The cases were divided into 2 groups, CLL (n = 107) and CLL + OM (n = 25), according to the presence of additional malignancy. Lymphocyte count (P = .014), white blood cell count (P = .006), and hemoglobin (P = .034) were significantly higher in the CLL group. Rai stage IV percentage (P = .015), Binet stage B percentage (P = .043), progression, and sepsis percentages (P = .008) were significantly higher in the CLL + OM group. Overall survival time was significantly lower in the CLL + OM group (P = .032). Most OMs had been diagnosed before CLL (63.64%) in the no-treatment group, while the majority of OMs were diagnosed after CLL (78.57%) in the treatment group (P = .032). CLL patients with OM had a more advanced CLL stage, and survival was significantly shorter in these patients. In addition, CLL-associated OM appears to occur more frequently in the post-treatment period.

Novel Approaches for the Treatment of Patients with Richter's Syndrome

OPINION STATEMENT

In the last 10-15 years, the way to treat cancers has dramatically changed towards precision medicine approaches. These treatment options are mainly based on selective targeting against signaling pathways critical for or detrimentally activated in cancer cells in cancer cells, as well as exploiting molecules that are specifically expressed on neoplastic cells, also known as tumor-associated antigens. These considerations hold true also in the hematological field where a plethora of novel targeted agents have reached patients' bedside, significantly improving clinical responses. Chronic lymphocytic leukemia (CLL) is an example of how targeted therapies, such as BTK, PI3K, or Bcl-2 inhibitors as well as anti-CD20 antibodies, have improved patients' management, even when adopted as frontline treatment. However, these advancements do not apply to Richter's syndrome (RS), the transformation of CLL into a very aggressive and fatal lymphoma, occurring in 2-10% of patients. RS is usually a fast-growing lymphoma of the diffuse large B cell or the Hodgkin's variant, with a dismal prognosis. Despite advancements in depicting and understanding the genetic background of RS and its pathogenesis, no significant clinical results have been registered. In the last couple of years, several studies have started to investigate the impact of novel drugs or drug combinations and some of them have opened for clinical trials, currently in phase I or II, whose results will be soon available. This review will present an overview of current and most recent therapeutic options in RS, discussing also how results coming from xenograft models may help in designing and identifying novel treatment opportunities to overcome the lack of effective therapies.

Richter Transformation in Chronic Lymphocytic Leukemia: Update in the Era of Novel Agents

Richter transformation (RT) is a poorly understood complication of chronic lymphocytic leukemia (CLL) with a dismal prognosis. It is associated with a switch in histopathology and biology, generally with a transformation of the original CLL clone to diffuse large B-cell lymphoma (DLBCL) or less frequently to Hodgkin's variant of Richter transformation (HVRT). It occurs in 2-10% of CLL patients, with an incidence rate of 0.5-1% per year, and may develop in treatment-naïve patients, although it is more common following therapy. In recent years, there has been a deeper understanding of the molecular pathogenesis of RT that involves the inactivation of the TP53 tumor suppressor gene in 50-60% of cases and the activation of aberrations of NOTCH1 and MYC pathways in about 30% of cases. Compared to the preceding CLL, 80% of cases with DLBCL-RT and 30% of HVRT harbor the same IGHV-D-J rearrangements, indicating a clonal evolution of the disease, while the remaining cases represent de novo lymphomas that are clonally unrelated. Despite advances in understanding the molecular variations and the pathogenesis of the disease, there is still no significant improvement in patient outcomes. However, if no clinical trials were designed for patients with RT in the past, now there many studies for these patients that incorporate new drugs and novel combinations that are being explored. In this review, we summarize the new information accumulated on RT with special emphasis on results involving the novel therapy tested for this entity, which represents an unmet clinical need.

Second cancer incidence in CLL patients receiving BTK inhibitors

Chronic lymphocytic leukemia (CLL) is associated with perturbed immune function and increased risk for second primary malignancies (SPM). Ibrutinib and acalabrutinib (BTKi) are effective therapies for CLL resulting in partial restoration of immune function. The incidence of and risk factors for SPM in CLL patients receiving BTKi are not yet characterized. We retrospectively determined the incidence of SPM in CLL patients treated with ibrutinib or acalabrutinib at our institution between 2009 and 2017, assessed for association between baseline characteristics and SPM incidence, and compared the observed to expected cancer incidence among age, sex, and year matched controls without CLL. After a median of 44 months follow-up, 64/691 patients (9%) were diagnosed with SPM (excluding non-melanoma skin cancer [NMSC]). The three-year cumulative incidence rate was 16% for NMSC and 7% for other SPM. On multivariable analysis, smoking was associated with increased SPM risk (HR 2.8 [95% CI: 1.6–4.8]) and higher baseline CD8 count was associated with lower SPM risk (HR 0.9 for 2-fold increase [95% CI: 0.8–0.9]). The observed over expected rate of SPM was 2.2 [95% CI: 1.7–2.9]. CLL patients treated with BTKi remain at increased risk for SPM, and secondary cancer detection is an important consideration in this population.

Richter transformation in chronic lymphocytic leukemia (CLL)-a pooled analysis of German CLL Study Group (GCLLSG) front line treatment trials

Richter transformation (RT) is defined as development of aggressive lymphoma in patients (pts) with CLL. The incidence rates of RT among pts with CLL range from 2 to 10%. The aim of this analysis is to report the frequency, characteristics and outcomes of pts with RT enrolled in trials of the GCLLSG. A total of 2975 pts with advanced CLL were reviewed for incidence of RT. Clinical, laboratory, and genetic data were pooled. Time-to-event data, starting from time of CLL diagnosis, of first-line therapy or of RT diagnosis, were analyzed by Kaplan-Meier methodology. One hundred and three pts developed RT (3%): 95 pts diffuse large B-cell lymphoma (92%) and eight pts Hodgkin lymphoma (8%). Median observation time was 53 months (interquartile range 38.1-69.5). Median OS from initial CLL diagnosis for pts without RT was 167 months vs 71 months for pts with RT (HR 2.64, CI 2.09-3.33). Median OS after diagnosis of RT was 9 months. Forty-seven pts (46%) received CHOP-like regimens for RT treatment. Three pts subsequently underwent allogeneic and two pts autologous stem cell transplantation. Our findings show that within a large cohort of GCLLSG trial participants, 3% of the pts developed RT after receiving first-line chemo- or chemoimmunotherapy. This dataset confirms the ongoing poor prognosis and high mortality associated with RT.

Multiple B cell malignancies in patients with chronic lymphocytic leukemia: epidemiology, pathology, and clinical implications

Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) is associated with increased risk for certain cancers, but relatively little is known about the risk for these patients to develop additional B cell malignancies. Here, we review the available epidemiological data on multiple B cell malignancies in CLL, discuss diagnostic methods and proper pathologic evaluation to distinguish CLL from other B cell malignancies, and address clinical challenges and unmet needs in caring for CLL patients with unrelated B cell malignancies and disease transformation. Considerations include CLL patients with unrelated monoclonal B cell lymphocytosis, biclonal CLL, secondary B cell non-Hodgkin lymphomas, and Richter syndrome - both clonally related transformation and de novo large B cell lymphoma. We address the challenges that remain in order to better understand the underlying risk factors and biology that may put CLL patients at increased risk of developing multiple B cell neoplasia.

Immunochemotherapy for Richter syndrome: current insights

Richter syndrome (RS) is recognized as the development of a secondary and aggressive lymphoma during the clinical course of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Most of such histological transformations are from RS to diffuse large B-cell lymphoma (DLBCL-RS, 90%) and Hodgkin’s lymphoma (HL-RS, 10%). Histopathological examination is a prerequisite for diagnosis. It is crucial to assess the relationship between the RS clone and the underlying CLL/SLL because clonally related DLBCL-RS has a poor outcome, while clonally unrelated cases have a prognosis similar to de novo DLBCL. An anti-CD20 antibody-based immunochemotherapy is hitherto the frontline treatment of choice for DLBCL-RS; nonetheless, the results are unsatisfactory. Allogeneic stem cell transplantation should be offered to younger and fit patients as a consolidative treatment; however, the majority of the patients may not be qualified for this procedure. The HL-RS transformation has better outcomes than those of DLBCL-RS and can effectively be treated by the adriamycin, bleomycin, vinblastine, and dacarbazine regimen. Although novel agents are currently being investigated for RS, immunochemotherapy nevertheless remains a standard treatment for DLBCL-RS.

Cancer Risk in Patients with Multiple Sclerosis: Potential Impact of Disease-Modifying Drugs

In the 1990s, the first disease-modifying therapies (DMTs) for multiple sclerosis (MS) were injectable immunomodulatory (IM) drugs, including four different interferon-β preparations and glatiramer acetate. Since 2000, more than 15 immunosuppressant (IS) drugs have been used, with a more or less specific action on inflammation. These include monoclonal antibodies targeting CTL4, the integrin receptor, the interleukin (IL)-2 receptor, CD19, CD20, CD52, and the sphingosine 1 phosphate family. The association between MS and cancer has long been investigated but has led to conflicting results. No studies have reported an increased risk of cancer after long-term exposure to IM. Several reports suggest an increase in cancer risk among MS patients treated with IS such as mitoxantrone, azathioprine and cyclophosphamide. Because of their action on the immune system, and due to a lack of available long-term data, a special warning of the potential risk of cancer accompanies the use of recent IS such as cladribine, fingolimod, natalizumab or alemtuzumab. In most studies, factors such as diet, smoking, solar radiation, and hormone therapy, all of which influence cancer risk, have not been considered. For fingolimod, natalizumab, alemtuzumab, dimethyl fumarate, teriflunomide, daclizumab and ocrelizumab, risk management plans outlined by regulatory agencies are mandatory. They allow prospective detection of some red flags, in particular those for the increased risk of cancer. We review the current evidence behind the increased risk of malignancy in MS patients receiving DMTs, and provide an overview of the DMTs that are currently in use and those in clinical trials. The known risks and benefits of these therapies will be considered.

Biology and treatment of Richter syndrome

Richter syndrome (RS) is the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL). Two pathologic variants of RS are recognized: namely, the diffuse large B-cell lymphoma (DLBCL) variant and the rare Hodgkin lymphoma (HL) variant. Histologic documentation is mandatory to diagnose RS. The clinical suspicion of RS should be based on clinical signs and symptoms. Differential diagnosis between CLL progression and RS and choice of the biopsy site may take advantage of positron emission tomography/computed tomography. Molecular lesions of regulators of proliferation (CDKN2A, NOTCH1, MYC) and apoptosis (TP53) overall associate with ∼90% of DLBCL-type RS, whereas the biology of the HL-type RS is largely unknown. The prognosis of the DLBCL-type RS is unfavorable; the outcome of HL-type RS appears to be better. The most important RS prognostic factor is the clonal relationship between the CLL and the aggressive lymphoma clones, with clonally unrelated RS having a better prognosis. Rituximab-containing combination chemotherapy for DLBCL is the most widely used treatment in DLBCL-type RS. Fit patients who respond to induction therapy should be offered stem cell transplantation (SCT) to prolong survival. Adriamycin, bleomycin, vinblastine, and dacarbazine is the preferred regimen for the HL-type RS, and SCT consolidation is less used in this condition.

Effect of first-line treatment on second primary malignancies and Richter's transformation in patients with CLL

This study aimed to assess the frequency of and the contributing factors for second primary malignancies (SPMs) and Richter's transformations (RTs) following first-line treatment of chronic lymphocytic leukemia within four phase II/III trials of the GCLLSG evaluating fludarabine (F) vs F+cyclophosphamide (FC), chlorambucil vs F, FC without or with rituximab, and bendamustine+R (BR). Among 1458 patients, 239 (16.4%) experienced either an SPM (N=191) or a RT (N=75). Solid tumors (N=115; 43.2% of all second neoplasias) appeared most frequently, followed by RTs (N=75; 28.2%). Patients showed a 1.23-fold increased risk of solid tumors in comparison to the age-matched general population from the German cancer registry. Age>65 (hazard ratio (HR) 2.1; P<0.001), male sex (HR 1.7; P=0.01), co-morbidities (HR 1.6; P=0.01) and number of subsequent treatments⩾1 (HR 12.1; P<0.001) showed an independent adverse prognostic impact on SPM-free survival. Serum thymidine kinase>10 U/l at trial enrollment (HR 3.9; P=0.02), non-response to first-line treatment (HR 3.6; P<0.001) and number of subsequent treatments⩾1 (HR 30.2; P<0.001) were independently associated with increased risk for RT.

Incidence and prognostic impact of other cancers in a population of long-term survivors of chronic lymphocytic leukemia

BACKGROUND

Information on the impact of other cancers (OCs) in long-term survivors (LTSs) of chronic lymphocytic leukemia (CLL) is limited.

PATIENTS AND METHODS

Patients with CLL who survived >10 years were defined as LTSs of CLL. We calculated standardized incidence ratios (SIRs) to compare the incidence of OC in LTS of CLL versus the general population. A multivariable model was used to identify independent predictors of OC. Overall survival was analyzed as a function of the presence of OC.

RESULTS

Among 797 LTSs of CLL, the cumulative frequency of OC was 36%, similar between 570 patients (72%) who required treatment for CLL (TRT) and 227 (28%) who remained untreated (UT). The most common OC in both groups was non-melanoma skin cancer, followed by prostate cancer, breast cancer, melanoma, lung cancer, and leukemia in TRT patients, and by prostate cancer, breast cancer, melanoma, lung cancer, and gastrointestinal tumors in the UT group. The SIR for all OC was 1.2 (P = 0.034). It was higher in males (SIR 1.31; P = 0.013) and patients <60 years (SIR 1.27; P = 0.027). A higher SIR was shown for secondary leukemia, melanoma, and head-and-neck cancers, whereas a lower SIR was found for gastrointestinal and bladder cancers. Independent predictors of OC development were advanced age, male gender, and lower platelets. The survival of patients with OC was 16.2 months and that of patients without OC 22.9 years.

CONCLUSIONS

LTSs of CLL have an increased incidence of OC compared with the general population. CLL therapy is not a risk factor for OC in LTSs of CLL. The presence of an OC in these patients may be associated with shorter survival.

Richter syndrome: pathogenesis and management

Richter syndrome (RS) is the development of an aggressive lymphoma in patients with a previous or concomitant diagnosis of chronic lymphocytic leukemia (CLL). The incidence rate RS is ~0.5% per year of observation. Two biomarkers (NOTCH1 mutations and subset 8 configuration of the B-cell receptor) may help identifying CLL patients at risk of RS to be considered for close monitoring and a careful biopsy policy. In the presence of clinical features suspicious of RS, diagnosis of transformation and choice of the site of biopsy may take advantage of fluorine 18 fluorodeoxyglucose ((18)FDG) positron emission tomography (PET)/computed tomography (CT). Molecular lesions of regulators of tumor suppression (TP53), cell cycle (CDKN2A), and cell proliferation (NOTCH1, MYC) overall account for ~90% of RS and may be responsible for the aggressive clinical phenotype observed in this disease because of the combined effect of chemoresistance and rapid disease kinetics. The prognosis of RS is generally highly unfavorable. However, the pattern of survival is not homogeneous and the most important prognostic factor is the clonal relationship between the CLL and the aggressive lymphoma clones. Rituximab-containing polychemotherapy represents the backbone for induction treatment in RS. Younger patients who respond to induction therapy should be offered stem cell transplant (SCT) to prolong survival.

Outcomes for patients with chronic lymphocytic leukemia and acute leukemia or myelodysplastic syndrome

Acute leukemia (AL) and myelodysplastic syndrome (MDS) are uncommon in chronic lymphocytic leukemia (CLL). We retrospectively identified 95 patients with CLL, also diagnosed with AL (n=38) or MDS (n=57), either concurrently (n=5) or subsequent (n=90) to CLL diagnosis and report their outcomes. Median number of CLL treatments prior to AL and MDS was 2 (0-9) and 1 (0-8), respectively; the most common regimen was purine analog combined with alkylating agent±CD20 monoclonal antibody. Twelve cases had no prior CLL treatment. Among 38 cases with AL, 33 had acute myelogenous leukemia (AML), 3 had acute lymphoid leukemia (ALL; 1 Philadelphia chromosome positive), 1 had biphenotypic and 1 had extramedullary (bladder) AML. Unfavorable AML karyotype was noted in 26, and intermediate risk in 7 patients. There was no association between survival from AL and number of prior CLL regimens or karyotype. Expression of CD7 on blasts was associated with shorter survival. Among MDS cases, all International Prognostic Scoring System (IPSS) were represented; karyotype was unfavorable in 36, intermediate in 6 and favorable in 12 patients; 10 experienced transformation to AML. Shorter survival from MDS correlated with higher risk IPSS, poor-risk karyotype and increased number of prior CLL treatments. Overall, outcomes for patients with CLL subsequently diagnosed with AL or MDS were very poor; AL/MDS occurred without prior CLL treatment. Effective therapies for these patients are desperately needed.

Melanoma and non-melanoma skin cancers in hairy cell leukaemia: a Surveillance, Epidemiology and End Results population analysis and the 30-year experience at Memorial Sloan Kettering Cancer Center

Few studies have examined melanoma and non-melanoma skin cancer (NMSC) incidence rates after a diagnosis of hairy cell leukaemia (HCL). We assessed 267 HCL patients treated at Memorial Sloan Kettering Cancer Center (MSKCC) and Surveillance, Epidemiology and End Results (SEER) data for melanoma and NMSC incidence rates after HCL. Incidence data from MSKCC patients demonstrated a 10-year combined melanoma and NMSC skin cancer rate of 11·3%, melanoma 4·4% and NMSC 6·9%. Molecular analysis of skin cancers from MSKCC patients revealed activating RAS mutations in 3/9 patients, including one patient with melanoma. Of 4750 SEER patients with HCL, 55 (1·2%) had a subsequent diagnosis of melanoma. Standardized incidence ratios (SIRs) did not show that melanoma was more common in HCL patients versus the general population (SIR 1·3, 95% CI 0·78-2·03). Analysis of SEER HCL patients diagnosed before and after 1990 (approximately before and after purine analogue therapy was introduced) showed no evidence of an increased incidence after 1990. A better understanding of any potential association between HCL and skin cancer is highly relevant given ongoing trials using BRAF inhibitors, such as vemurafenib, for relapsed HCL, as RAS-mutant skin cancers could be paradoxically activated in these patients.

Richter syndrome in chronic lymphocytic leukemia: updates on biology, clinical features and therapy

Richter syndrome (RS) or Richter transformation is the development of secondary aggressive lymphoma in the setting of underlying chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Most frequently CLL transforms into diffuse large B-cell lymphoma (DLBCL) (90%) and rarely (10%) into Hodgkin lymphoma, termed Hodgkin variant of Richter syndrome (HvRS). RS is generally characterized by an aggressive clinical course and poor prognosis. In recent years, major advances have been made in understanding genetic events which relate to the progression of CLL or transformation into RS. Better understanding of the molecular pathways has revealed that RS is not a single homogeneous entity. The majority of cases are clonally related to the original CLL clone, while a minority develop from an unrelated clone. This review summarizes new data relating to the molecular biology and the genetic/epigenetic changes occurring during Richter transformation, and also considers the clinical features and therapy for both DLBCL-RS and Hodgkin variant-RS.

Revisiting the role of cladribine in acute myeloid leukemia: an improvement on past accomplishments or more old news?

Originally studied in lymphoid diseases, cladribine (CdA) is an adenosine deaminase resistant analog of adenosine that was later discovered to induce myeloid cell apoptosis. The activity of CdA in myeloid malignancies was first reported in relapsed/refractory (RR) pediatric acute myeloid leukemia (AML) with complete response (CR) rates of up to 47%. Consequently, several studies have confirmed the efficacy of single agent CdA or CdA combination regimens in AML. Established CR rates for combination regimens in RR adults are approximately 50%, while CR rates for newly diagnosed (ND) adults are approximately 70% and show similar toxicity profiles to previously used regimens. Despite these promising data, many centers have yet to adopt CdA combination regimens for these difficult to treat populations. We review the pharmacology, pharmacokinetics, clinical data, and safety of CdA monotherapy and combination regimens for the management of pediatric and adult ND and RR-AML.

Second cancers in patients with chronic lymphocytic leukemia who received frontline fludarabine, cyclophosphamide and rituximab therapy: distribution and clinical outcomes

Patients with chronic lymphocytic leukemia (CLL) are known to have an increased incidence of second cancers, but the contribution of commonly used frontline therapies to the incidence of second cancers is unclear. We report on the characteristics, incidence, outcomes and factors associated with second cancers in 234 patients receiving fludarabine, cyclophosphamide and rituximab (FCR) based regimens in the frontline setting. The risk of second cancers was 2.38 times higher than the expected risk in the general population. Ninety-three patients (40%) had other cancers before and 66 patients (28%) after FCR. Rates of therapy related acute myeloid leukemia/myelodysplastic syndrome (t-AML/MDS) (5.1%) and Richter transformation (RT) (9%) were high, while solid tumors were not increased. Overall survival of patients with second cancers after frontline FCR was shorter (median of 4.5 years) compared to patients with and without prior cancers. Second cancer risk after frontline FCR is mainly due to high rates of t-AML/MDS and RT, and as speculated the survival of affected patients is shorter.

Optimal management of skin cancer in immunosuppressed patients

Skin cancer is the most common malignancy in humans with basal cell carcinoma representing the majority of cases in the general population. The prevalence of skin cancer is increased amongst immunosuppressed patients such as those with lymphoproliferative disorders including non-Hodgkin lymphoma and chronic lymphocytic leukemia or those with iatrogenic immunosuppression following organ transplantation. In addition, these patients experience greater morbidity and mortality associated with skin cancers. The most common skin cancer in immunosuppressed patients is squamous cell carcinoma, which often presents with more aggressive features and has a greater rate of metastasis. This article reviews the risk factors, etiology, clinical presentation, and prevalence of skin cancer amongst immunosuppressed patients, including organ transplant, lymphoproliferative disorders, autoimmune disorders, and human immunodeficiency virus. We also provide a comprehensive review of treatment guidelines for immunosuppressed patients with cutaneous malignancy. Surgical therapy is the cornerstone of treatment; however, we also discuss pharmacologic treatment options, lifestyle modifications, and revision of immunosuppressive regimens.

Second Malignancies and Richter's Syndrome in Patients with Chronic Lymphocytic Leukemia

Second malignancies are frequent complications in patients with chronic lymphocytic leukemia (CLL). Patients with this leukemia may develop large cell lymphoma (LCL) known as Richter's syndrome (RS). RS occurs in CLL patients of about 3% and may develop in a single lymph node or more often in a group of nodes. However, in some patients extranodal localization of aggressive lymphoma in RS has been observed. Besides LCL, Hodgkin's disease, prolymphocytoid leukemia, multiple myeloma and acute lymphoblastic leukemia may also occur as RS variants. The origin of lymphoid cells in RS remains tentative. However, CLL and RS originate from the same clone for some patients, whereas, in other patients cells of aggressive lymphoma do not have the features of the same clone as the CLL cells. The prognosis of RS is poor. Survival in different studies will be usually 2-5 months. The secondary development or coexistence of myeloproliferative disorders or myelodysplastic syndrome and solid tumors have also been rarely documented in CLL patients. It is of great concern that therapy may further increase the risk of a second neoplasm. However, until now, there are no clear evidence that alkylating agents or purine nucleoside analogs may be associated with an increased incidence of second malignancies in patients with CLL. In this review, epidemiology, biology, clinical characteristic and treatment approaches in RS and other secondary neoplasms in patients with CLL are discussed.

Diffuse large B-cell lymphoma (Richter syndrome) in patients with chronic lymphocytic leukaemia (CLL): a cohort study of newly diagnosed patients

Nearly all information about patients with chronic lymphocytic leukaemia (CLL) who develop diffuse large B-cell lymphoma [Richter syndrome (RS)] is derived from retrospective case series or patients treated on clinical trials. We used the Mayo Clinic CLL Database to identify patients with newly diagnosed CLL between January 2000 and July 2011. Individuals who developed biopsy-proven RS during follow-up were identified. After a median follow-up of 4 years, 37/1641 (2·3%) CLL patients developed RS. The rate of RS was approximately 0·5%/year. Risk of RS was associated with advanced Rai stage at diagnosis (P < 0·001), high-risk genetic abnormalitites on fluorescence in situ hybridization (P < 0·0001), unmutated IGHV (P = 0·003), and expression of ZAP70 (P = 0·02) and CD38 (P = 0·001). The rate of RS doubled in patients after treatment for CLL (1%/year). Stereotyped B-cell receptors (odds-ratio = 4·2; P = 0·01) but not IGHV4-39 family usage was associated with increased risk of RS. Treatment with combination of purine analogues and alkylating agents increased the risk of RS three-fold (odds-ratio = 3·26, P = 0·0003). Median survival after RS diagnosis was 2·1 years. The RS prognosis score stratified patients into three risk groups with median survivals of 0·5 years, 2·1 years and not reached. Both underlying characteristics of the CLL clone and subsequent CLL therapy influence the risk of RS. Survival after RS remains poor and new therapies are needed.

Richter syndrome

Transformation of chronic lymphocytic leukemia (CLL) to aggressive lymphoma is known as Richter syndrome (RS). In the CLL population considered as a whole, the prevalence of RS development ranges from 2 to 7 %. The most common pathologic phenotype at the time of RS transformation is diffuse large B-cell lymphoma (DLBCL), while, in a small fraction of cases, the transformed phase shows pathologic features mimicking Hodgkin lymphoma. TP53 disruption and MYC activation cooperate as dual hits in driving DLBCL transformation. Two biomarkers (NOTCH1 mutations and usage of the immunoglobulin VH CDR3 subset 8) may help in identifying CLL patients at risk of DLBCL transformation to be considered for close monitoring and a careful biopsy policy. In the presence of clinical features suspicious of RS, diagnosis of transformation and choice of the site of biopsy may take advantage of (18)FDG PET/CT. The prognosis of RS transformation is generally highly unfavorable. However, the pattern of survival is not homogeneous and may be predicted on clinical and biological grounds. RS that are clonally unrelated to the paired CLL phase are biologically and clinically different from clonally related cases, and should be considered, and probably managed, as a de novo DLBCL arising in the context of CLL. Rituximab-containing polychemotherapy represents the backbone for induction treatment in patients with clonally related DLBCL transformation. Younger patients who respond to induction therapy should be offered stem cell transplant to prolong survival.

Autologous Stem Cell Transplantation for Chronic Lymphocytic Leukemia - Still a Valid Treatment Option, or is the Game Over?

Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) has been established as the current standard of care for young and fit patients with chronic lymphocytic leukemia (CLL). In the early nineties of the last century, long before the advent of fludarabine or antibody-based strategies, there was realistic hope that myeloablative therapy followed by autologous stem cell transplantation (autoSCT) might be an effective and potentially curative front-line treatment option for suitable patients with CLL. Since then, several prospective trials have disenthralled this hope: although autoSCT can prolong event and progression-free survival if used as part of early front-line treatment, it does not improve overall survival, while it is associated with an increased risk of late adverse events such as secondary malignancies. In addition, autoSCT lacks the potential to overcome the negative impact of biomarkers that confer resistance to chemotherapy or early relapse. The role of autoSCT has also been explored in the context of FCR, and it was demonstrated that its effect is inferior to the currently established optimal treatment regimen. In view of ongoing attempts to improve on FCR, promising clinical activity of new substances even in relapsed/ refractory CLL patients, exciting novel cell therapy approaches and advantages in the understanding of the disease and detection of Minimal Residual Disease (MRD), autoSCT has lost its place as a standard treatment option for CLL.

The impact of initial fludarabine therapy on transformation to Richter syndrome or prolymphocytic leukemia in patients with chronic lymphocytic leukemia: analysis of an intergroup trial (CALGB 9011)

The impact of initial fludarabine therapy on transformation to Richter syndrome (RS) or prolymphocytic leukemia (PLL) in patients with chronic lymphocytic leukemia (CLL) is uncertain. We studied the outcomes of 521 patients with CLL who were randomized to initial fludarabine (F), chlorambucil (C) or F + C therapy on an intergroup trial (CALGB 9011). RS developed in 34 (7%) patients and PLL in 10 (2%). RS and PLL occurred in 14 (7%) and three (2%) of 188 patients randomized to F; nine (5%) and four (2%) of 191 patients treated with C; and 11 (8%) and three (2%) of 142 receiving F + C, respectively. Four percent of the 206 patients with Rai stage III/IV developed PLL, compared to only 1% of the 315 patients with Rai stage I/II (p = 0.02). Initial fludarabine therapy in patients with CLL did not impact transformation to RS or PLL, nor were any other baseline characteristics predictive for such transformation in this series.

Therapy-Related Myeloid Neoplasms in Chronic Lymphocytic Leukemia and Waldenstrom's Macroglobulinemia

Secondary myelodysplasia (MDS) and acute myeloid leukemia (AML) are frequent long term complications in Chronic Lymphocytic Leukemia (CLL) and Waldenström Macroglobulinemia (WM) patients. Although disease-related immune-suppression plays a crucial role in leukemogenesis there is great concern that therapy may further increase the risk of developing these devastating complications.Nucleoside analogs (NA) and alkylating agents are considered appropriate agents in the treatment of both CLL and WM patients. Prolonged immunosuppression related to NA therapy and the incorporation of these agents or their metabolites into DNA, with potentially mutagenic action, leads to speculation that their therapeutic use might be responsible for an increased incidence of second cancer especially when combined with other DNA damaging agents like alkylating agents.In this review the published studies considering the occurrence of secondary MDS and AML in CLL and WM patients are reported and the potential role of chemotherapeutic agents in leukemogenesis is discussed.

Use of white blood cell growth factors and risk of acute myeloid leukemia or myelodysplastic syndrome among elderly patients with non-Hodgkin lymphoma

BACKGROUND

The current study was conducted to evaluate the association between colony-stimulating factor (CSF) use and the risk of developing therapy-related myelodysplastic syndromes or acute myeloid leukemia (t-MDS/AML) among a large cohort of elderly patients with non-Hodgkin lymphoma (NHL) who were treated with chemotherapy.

METHODS

A total of 13,203 NHL patients were identified from the Surveillance, Epidemiology, and End Results-Medicare database who were diagnosed from 1992 through 2002. Patients were followed from their initial chemotherapy date until the date they were diagnosed with t-MDS/AML, death, or last follow-up (October 31, 2006), whichever occurred first.

RESULTS

Overall, 40% (n = 5266) of patients received CSF. During the follow-up period (median follow-up, 2.9 years [range, 1-14.7 years]), 272 (5.2%) patients who were treated with CSF developed t-MDS/AML, compared with 230 (2.9%) patients who did not (P < .0001, log-rank test). The 5-year incidence of t-MDS/AML for patients receiving CSF was 14.1 per 1000 person-years compared with 8.3 per 1000 person-years for patients not receiving CSF. In a multivariable Cox regression analysis adjusted for gender, histology, stage, comorbidities, radiotherapy, and chemotherapy agent, CSF use was found to be independently associated with a 53% increased risk of t-MDS/AML (hazard ratio [HR], 1.53; 95% confidence interval [95% CI], 1.26-1.84). The observed association between CSF use and t-MDS/AML persisted across histologic subgroups (ie, diffuse large B-cell lymphoma, follicular lymphoma, and others). Patients who received both CSF and antimetabolite chemotherapy were found to have a 2.5-fold increased risk of t-MDS/AML (HR, 2.49; 95% CI, 1.91-3.26) compared with patients who received neither agent.

CONCLUSIONS

The current study, which to our knowledge is the first large population-based study published to date, demonstrated that the administration of CSF among elderly NHL patients receiving chemotherapy was associated with an increased risk of t-MDS/AML, although the absolute risk was low.

A systematic review on Richter syndrome: what is the published evidence?

A systematic and comprehensive search of literature was performed using MEDLINE databases from 1st January 1978 to 2nd November 2009 and hand search of references. A search performed by combining the Medical Subject Headings (MESH) terms 'Richter's syndrome' and 'chronic lymphocytic leukemia' (CLL) yielded 143 citations. Ten additional case-control studies judged relevant for the purpose of study were also included. In total, 45 case reports, 18 case series, and 9 case-control studies were identified. For the purpose of this review, only case series and case-control studies were considered. The following conclusions could be drawn from the studies analyzed in this review: (i) some biological markers (i.e. CD38 expression and genotype, absence of del13q) or clinical features (i.e. bulky lymph node involvement), although not validated in prospective trials, may be considered for close monitoring and a careful biopsy policy; (ii) PET, is not yet standardized in RS, however, it may be useful in the diagnosis and to choose the site for biopsy; (iii) when diagnosed RS should be treated with a combination of rituximab and polychemotherapy; (iii) younger patients who respond to initial therapy should be offered allogeneic SCT, if feasible. Despite the paucity of data, it is important to note that this article represents the first systematic review of the entire body of available clinical evidence useful for an appropriate management of Richter transformation.

Second malignancy risks after non-Hodgkin's lymphoma and chronic lymphocytic leukemia: differences by lymphoma subtype

PURPOSE

Previous studies have shown increased risks of second malignancies after non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL); however, no earlier investigation has quantified differences in risk of new malignancy by lymphoma subtype.

PATIENTS AND METHODS

We evaluated second cancer and leukemia risks among 43,145 1-year survivors of CLL/small lymphocytic lymphoma (SLL), diffuse large B-cell lymphoma (DLBCL), or follicular lymphoma (FL) from 11 Surveillance, Epidemiology, and End Results (SEER) population-based registries during 1992 to 2006.

RESULTS

Among patients without HIV/AIDS-related lymphoma, lung cancer risks were significantly elevated after CLL/SLL and FL but not after DLBCL (standardized incidence ratio [SIR], CLL/SLL = 1.42, FL = 1.28, DLBCL = 1.00; Poisson regression P for difference among subtypes, P(Diff) = .001). A similar pattern was observed for risk of cutaneous melanoma (SIR: CLL/SLL = 1.92, FL = 1.60, DLBCL = 1.06; P(Diff) = .004). Acute nonlymphocytic leukemia risks were significantly elevated after FL and DLBCL, particularly among patients receiving initial chemotherapy, but not after CLL/SLL (SIR: CLL/SLL = 1.13, FL = 5.96, DLBCL = 4.96; P(Diff) < .001). Patients with HIV/AIDS-related lymphoma (n = 932) were predominantly diagnosed with DLBCL and had significantly and substantially elevated risks for second anal cancer (SIR = 120.50) and Kaposi's sarcoma (SIR = 138.90).

CONCLUSION

Our findings suggest that differing immunologic alterations, treatments (eg, alkylating agent chemotherapy), genetic susceptibilities, and other risk factors (eg, viral infections, tobacco use) among lymphoma subtypes contribute to the patterns of second malignancy risk. Elucidating these patterns may provide etiologic clues to lymphoma as well as to the second malignancies.

2-Chlorodeoxyadenosine treatment for cutaneous T-cell lymphoma

The primary cutaneous lymphomas are often indolent but difficult to treat. In the early stages psoralen and ultraviolet-A therapy is the standard treatment whereas at the tumor stage chemotherapy (e.g. pegylated doxorubicin) is often used for debulking. The purine analog 2-chlorodeoxyadenosine (2CdA) acts in non-Hodgkin’s lymphoma and has been used in our center for the treatment of advanced primary cutaneous T-cell lyphomas (CTCL). Here, we report on the efficacy and side effects of 2CdA in six patients with CTCL. One patient died owing to myelosuppression. Partial responses were seen in four cases but full remission was observed in only one case. We concluded that 2CdA has a limited usefulness in the management of advanced CTCL.

Beyond hairy cell: the activity of cladribine in other hematologic malignancies

Before the contemporary development of rationally designed antineoplastic therapies, cladribine was identified as a lymphocyte-specific agent. Its profound impact on the natural history of hairy cell leukemia, with responses approaching 100% and a median duration of response of nearly a decade after only a single 7-day course, is well known and revolutionized the treatment of hairy cell leukemia. However, cladribine's impressive activity in other lymphoproliferative disorders has been generally underappreciated. Multiple single-arm phase 2 trials have demonstrated cladribine's potency across the full spectrum of lymphoid malignancies. In a limited number of phase 3 trials and cross-study analyses, cladribine compared favorably with fludarabine, another purine nucleoside analog that is more commonly used in the treatment of indolent lymphoid malignancies. Cladribine has been noted to have particular activity among lymphoid disorders with few effective therapies, specifically, chronic lymphocytic leukemia, lymphoplasmacytic lymphoma, marginal zone lymphoma, and mantle cell lymphoma. Recently approved novel agents may act in synergy with cladribine for these conditions and should be incorporated into future clinical studies.

Skin lesions in chronic lymphocytic leukemia

Cutaneous lesions occur in up to 25% of patients with chronic lymphocytic leukemia (CLL). These can be caused by either cutaneous seeding by leukemic cells (leukemia cutis, LC) and other malignant diseases or nonmalignant disorders. Skin infiltration with B-lymphocyte CLL manifests as solitary, grouped, or generalized papules, plaques, nodules, or large tumors. Prognosis in CLL patients with LC is rather good and many authors claim that it does not significantly affect patients' survival. However, prognosis is poor in patients in whom LC shows blastic transformation (Richter's syndrome) and when leukemic infiltrations in the skin appear after the diagnosis of CLL. Secondary cutaneous malignancies are also frequent complications in patients with CLL. A higher risk was seen in skin cancer, for which eightfold higher occurrence has been stated. There are some suggestions that alkylating agents and purine analogs may be associated with an increased incidence of secondary malignancies in CLL. Nonspecific, secondary cutaneous lesions are frequently observed in CLL patients. The most common secondary cutaneous changes seen in CLL are those of infectious or hemorrhagic origin. Other secondary lesions present as vasculitis, purpura, generalized pruritus, exfoliative erythroderma, and paraneoplastic pemphigus. An exaggerated reaction to an insect bite and insect bite-like reactions have been also observed.

Current status of older and new purine nucleoside analogues in the treatment of lymphoproliferative diseases

For the past few years more and more new cytotoxic agents active in the treatment of hematological malignancies have been synthesized and become available for either in vitro studies or clinical trials. Among them the class of antineoplastic drugs belonging to the purine nucleoside analogues group (PNAs) plays an important role. Three of them: pentostatin (DCF), cladribine (2-CdA) and fludarabine (FA) were approved by Food and Drug Administration (FDA) for the treatment of hematological malignancies. Recently three novel PNAs: clofarabine (CAFdA), nelarabine (ara-G) and forodesine (immucillin H, BCX-1777) have been synthesized and introduced into preclinical studies and clinical trials. These agents seem to be useful mainly for the treatment of human T-cell proliferative disorders and they are currently undergoing clinical trials in lymphoid malignancies. However, there are also several studies suggesting the role of these drugs in B-cell malignancies. This review will summarize current knowledge concerning the mechanism of action, pharmacologic properties, clinical activity and toxicity of PNAs accepted for use in clinical practice, as well as new agents available for clinical trials.

Fludarabine in the treatment of chronic lymphocytic leukemia: a review

Fludarabine (FAMP) is the most effective and most extensively studied purine analog in indolent B-cell malignancies. Its use is indicated for first-and second-line treatment of B-cell chronic lymphocytic leukemia (B-CLL). FAMP as a single agent has produced superior response rates and progression-free survival than standard therapy with chlorambucil and alkylator-based regimen. Efficacy of FAMP may be increased by combining this purine analog with other chemotherapeutic and non-chemotherapeutic agents. FAMP and cyclophosphamide combination (FC) has shown promising results with higher overall response and complete response rates than FAMP in monotherapy, although no difference has been detected in survival. Quality of response and eradication of minimal residual disease (MRD) have been reported to be associated with prolonged survival. Eradication of MRD has been achieved by combining FC with mitoxantrone or monoclonal antibody including alemtuzumab or rituximab or both. FAMP has been widely used in non-myeloablative conditioning regimens, often combined with a variety of other cytotoxic agents, with the aim of inducing enough immunosuppression to allow successful engraftment and to exert some pretransplant anti-tumor activity. The current paper provides an overview of use of FAMP as a single agent or as a cornerstone of different therapeutic strategies for treatment of B-CLL patients.

Intrinsic and treatment-related immune alterations in chronic lymphocytic leukaemia and their impact for clinical practice

BACKGROUND

Chronic lymphocytic leukaemia patients harbour important impairments in both their cellular- and humoral-mediated immunity, which accounts for their notorious susceptibility to a multitude of infections and various autoimmune cytopenias. It has also been shown that the rate of second cancers is increased in chronic lymphocytic leukaemia.

OBJECTIVE

The aim of this study was to review the immune alterations in untreated and treated chronic lymphocytic leukaemia and define their impact for clinical practice.

METHODS

The author gives a comprehensive review of the most relevant preclinical and clinical studies pertaining to various immune abnormalities and infectious complications in both untreated and treated chronic lymphocytic leukaemia. Landmark clinical trials involving the contemporary chronic lymphocytic leukaemia chemo- and immunotherapies, alone or in combination, as well as the main epidemiological studies establishing the increased rate of second cancers in chronic lymphocytic leukaemia are also discussed.

RESULTS/CONCLUSIONS

Iatrogenic immunosuppression in chronic lymphocytic leukaemia alters the pattern of opportunistic infections, can cause autoimmune cytopenias and might further increase the rate of second malignancies in patients whose disease already places them at a greater risk. Careful consideration of existing risk factors in chronic lymphocytic leukaemia could establish the optimal screening and follow-up schedule for chronic lymphocytic leukaemia patients as its therapeutics evolves.

Risk factors for development of a second lymphoid malignancy in patients with chronic lymphocytic leukaemia

Previous studies suggested that patients with chronic lymphocytic leukaemia (CLL) are at a three- to fivefold increased risk of developing a second lymphoproliferative disorder (LPD). This observational cohort study used the Mayo Clinic CLL Database to identify factors associated with developing a second LPD. A second LPD was identified in 26 (2.7%) of 962 CLL patients during a median follow-up of 3.3 years. Diffuse large B-cell lymphoma was the most common subtype of secondary LPD (12 of 26 cases). Patients previously treated for CLL had a trend toward higher prevalence of second LPD (4%) compared with previously untreated patients (2%; P = 0.053). More strikingly, patients treated with purine nucleoside analogues (PNA) had a significantly increased risk of subsequent second LPD (5.2%) compared with patients who had not received PNA (1.9%; P = 0.008). No statistically significant association was observed between risk of second LPD and other CLL characteristics (ZAP-70, CD38, IgV(H) mutation status or cytogenetic abnormalities). In this series, prior treatments with PNA or anthracyclines were the only significant factors associated with risk of developing a second LPD in patients with CLL. Physicians should strictly adhere to established criteria to initiate treatment for CLL patients who are not participating in clinical trials.

Prolonged follow-up after initial therapy with 2-chlorodeoxyadenosine in patients with indolent non-Hodgkin lymphoma: results of Cancer and Leukemia Group B Study 9153

BACKGROUND

The objective of this study was to determine the efficacy and toxicity of 2-chlorodeoxyadenosine (2-CdA) in patients with untreated, indolent non-Hodgkin lymphoma (NHL).

METHODS

For this multicenter, single-arm, Phase II study, 44 patients with treatment-naive, stage III or IV, indolent NHL (International Working Formulation subtypes A, B, and C) were enrolled. Patients received 0.14 mg/kg per day of 2-CdA as a 2-hour bolus infusion for 5 consecutive days every 28 days until maximal response or a total of 6 cycles.

RESULTS

Thirty-eight patients were eligible for response evaluation. The overall response rate was 100% (95% confidence interval [95% CI], 90.8-100%), and the complete response rate was 31.6% (95% CI, 17.5-48.7%). In the intent-to-treat population, the median failure-free survival was 2.0 years (95% CI, 1.3-3.4 years), and the overall survival rate was 7.0 years (95% CI, 4.3-9.4 years). Six patients had sustained remissions that lasted a median of 8.7 years (range, from 5.9 years to > or =11 years). Although 68% of patients experienced at least 1 grade 3 or 4 event, consisting primarily of myelosuppression, severe infections were rare, with only 8 grade 3 infections. Four late malignancies (prostate adenocarcinoma, ductal carcinoma in situ, and myelodysplasia) and 4 patients with large cell transformation were reported.

CONCLUSIONS

2-CdA is an active, well-tolerated therapy for patients with untreated, indolent NHL.

Incidence of second neoplasia in patients with B-cell chronic lymphocytic leukemia treated with chlorambucil maintenance chemotherapy

The aim of this retrospective study was to examine the impact of prolonged chlorambucil (CLB) therapy on the development of second neoplasia (SN) in 389 patients with B-CLL, comparing untreated cases with those receiving CLB as induction plus maintenance therapy. Fifty-nine SN cases were observed (15.1%) at a median follow-up of 79 months. SN occurrence was significantly related to Binet stage. No difference was detected between untreated and CLB treated cases neither in terms of SN incidence (12.2% vs 18.1%) nor in the median follow-up (81 vs 79.1 months). Moreover, SN free survival was not different between these two groups. Four out of 13 CLB treated patients (30.8%) developed s-MDS after a subsequent treatment with fludarabine plus cyclophosphamide (F + C). In conclusion, SN development is dependent on the length of follow-up rather than on therapy duration. F + C should be administered with caution after prolonged CLB therapy.

Risk of second cancer after chronic lymphocytic leukemia

Smoking is not considered a risk factor for chronic lymphocytic leukemia (CLL) yet increased lung cancer risk has been reported for these patients. Little data exist on the temporal variation in lung cancer risk after CLL, or its histological composition. We investigated the occurrence of second cancers in a large cohort of CLL patients with particular emphasis on lung cancer and its major subtypes. We followed all patients diagnosed with CLL in Denmark in the period 1943-2003 (n = 12,373) for the occurrence of second cancers. The relative risk was expressed as the standardized incidence ratio (SIR), i.e. the ratio of observed to expected number of cancers, based on incidence rates for the Danish population. During follow-up 1,105 cancers occurred among the CLL patients (SIR = 1.59 (95% CI 1.50-1.69)). SIR for all cancers combined remained elevated more than 10 years after CLL (SIR = 1.80 (1.56-2.08)). Lung cancer occurred in 141 patients (SIR = 1.61 (1.37-1.90)). The relative risk of lung cancer did not vary by gender, or time of follow-up, but was higher in younger (SIR(<60 years) = 2.22 (1.62-3.06)) than in older (SIR(70-79 years) = 1.21 (0.88-1.68)) age-groups. Elevated risks were observed for adenocarcinoma (SIR = 2.20 (1.57-3.08)) and squamous cell carcinoma (SIR = 1.52 (1.06-2.17)) of the lung. We speculate that shared genetic risk factors may explain the accumulation of lung and other cancers in CLL patients.

Role of fludarabine in hematological malignancies

Fludarabine is a prodrug that is converted to the free nucleoside 9-beta-D-arabinosyl-2-fluoroadenine (F-ara-A), which enters cells and accumulates mainly as the 5'-triphosphate, F-ara-ATP. F-ara-ATP has multiple mechanisms of action, which are mostly directed toward DNA. Collectively, these actions affect DNA synthesis, which is the major mechanism of F-ara-A-induced cytotoxicity. Secondarily, incorporation into RNA and inhibition of transcription has been shown in cell lines. As a single agent, fludarabine has been effective for indolent leukemia. Biochemical modulation strategies resulted in enhanced accumulation of cytarabine triphosphate and led to the use of fludarabine for the treatment of acute leukemia. The combination of fludarabine with DNA-damaging agents to inhibit DNA repair processes has been highly effective for indolent leukemia and lymphomas. Other strategies have incorporated fludarabine into preparative regimens for nonmyeloablative stem-cell transplantation.

Richterʼs Syndrome

Richter's syndrome, that is, transformation of chronic lymphocytic leukemia to a large cell or immunoblastic lymphoma, occurs in up to 10% of patients with chronic lymphocytic leukemia. The onset of Richter's syndrome is characterized by worsening systemic symptoms, rapid tumor growth, and/or extranodal involvement. Median survival with conventional chemotherapy is less than 6 months. Therapy with more recent therapeutic regimens, such as hyperCVXD (fractionated cyclophosphamide, vincristine, liposomal daunorubicin, and dexamethasone), augmented hyperCVXD, and yttrium-90 ibritumomab tiuxetan, has not produced major improvements in response rates or overall survival. Improvement in the outcome of patients with Richter's syndrome may be aided by a more comprehensive understanding of the pathogenesis of Richter's syndrome; therapy could then be targeted against specific abnormalities. Current data indicate that the transformation of chronic lymphocytic leukemia to a large-cell or immunoblastic lymphoma is associated with abnormalities in cell cycle regulation (e.g., loss of the cell cycle inhibitors p16(INK4a) and p27(KIP1) ) and DNA repair (e.g., mutations and/or deletions of the p53, ATM, and p14(ARF) genes and epigenetic silencing of the MLH1 gene). However, the critical event leading to transformation is unclear. Given the poor prognosis of patients with Richter's syndrome, every effort should be made to enroll these patients into clinical trials evaluating novel agents with the appropriate correlative studies.

Therapy of Chronic Lymphocytic Leukaemia with Purine Nucleoside Analogues

Chronic lymphocytic leukaemia (CLL) is a neoplastic disease of unknown aetiology characterised by an absolute lymphocytosis in peripheral blood and bone marrow. The disease is diagnosed most commonly in the elderly with the median age at diagnosis being about 65 years. The purine nucleoside analogues (PNAs) fludarabine, cladribine (2-chlorodeoxyadenosine) and pentostatin (2'-deoxycoformycin) are highly active in CLL, both in previously treated and in refractory or relapsed patients. These three agents share similar chemical structures and mechanisms of action such as induction of apoptosis. However, they also exhibit significant differences, especially in their interactions with enzymes involved in adenosine and deoxyadenosine metabolism. Recent randomised studies suggest that fludarabine and cladribine have similar activity in CLL. However, clinical observations indicate the existence of cross-resistance between fludarabine and cladribine. Patients who received PNAs as their initial therapy and achieved long-lasting response can be successfully retreated with the same agent. PNAs administered in combination with other chemotherapeutic agents and/or monoclonal antibodies may produce higher response rates, including complete response (CR) or molecular CR, compared with PNAs alone or other treatment regimens. Management decisions are more difficult in elderly patients because of the apparent increase in toxicity of PNAs in this population. In elderly patients, we recommend chlorambucil as the first-line treatment, with PNAs in lower doses in refractory or relapsed patients. Myelosuppression and infections, including opportunistic varieties, are the most frequent adverse effects in patients with CLL treated with PNAs. Therefore, some investigators recommend routine antibacterial and antiviral prophylaxis during and after PNA treatment. This review presents current results and treatment strategies with the use of PNAs in CLL, especially in elderly patients.

The place of cladribine in the treatment of chronic lymphocytic leukemia: a 10-year experience in Poland

Cladribine (2-CdA) is structurally similar to another purine analog, fludarabine (FA), recently accepted in several centers as the first-line treatment in chronic lymphocytic leukemia (CLL). Unfortunately, there is less experience with the use of 2-CdA than with FA in patients with CLL in the majority of Western countries. In the last decade we performed several phase II studies and two phase III randomized trials to evaluate the activity and toxicity of 2-CdA in previously treated and untreated patients with CLL. We have also compared the results of Polish studies with the data presented by other investigators. Similarly to FA this agent has been found to be more effective in previously untreated CLL than in patients refractory to or relapsed after conventional therapy with alkylating agents. In different studies the overall response (OR) rate ranged from 70 to 85% and complete response (CR) from 10 to 47%. Higher CR and OR rates in CLL patients treated with 2-CdA and prednisone than with chlorambucil and prednisone were confirmed in our multicenter, randomized study. Subsequently, we performed a multicenter, randomized study comparing 2-CdA alone with a combination of 2-CdA and cyclophosphamide (CC) or cyclophosphamide and mitoxantrone (CMC). Our updated results seem to indicate that the CC program used as a first-line therapy in CLL gives higher CR and OR and better elimination of minimal residual disease (MRD) than 2-CdA alone. CC is also less myelotoxic than CMC. More recently, we have undertaken a phase II study to determine the efficacy and toxicity of 2-CdA combined with the anti-CD20 monoclonal antibody rituximab in CLL and other refractory or relapsed indolent lymphoproliferative disorders. The preliminary results seem to be better than in similar patients previously treated in our institution with 2-CdA alone. In conclusion, the studies performed in the last decade in Poland and other countries have shown that 2-CdA used alone or in combination with other agents is, similarly to FA, a highly active and relatively safe agent in previously treated and untreated patients with CLL.