Clinical and therapeutic implications of the mutational status of IgVH in patients with chronic lymphocytic leukemia

Outcomes of patients diagnosed with chronic lymphocytic leukemia after allogeneic hematopoietic stem cell transplantation: Results from a tertiary care center

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is currently the only curative treatment for patients with chronic lymphocytic leukemia (CLL).

METHODS

We analyzed the outcomes of 93 patients (median age: 52 years) who underwent allo-HCT at our center between 1989 and 2019.

RESULTS

After a median follow-up of 35 months, relapse was observed in 15.1% (n = 14) patients. The estimated 2-year non-relapse mortality, relapse-free survival, and overall survival (OS) were 38.1%, 54.2%, and 58.7%, respectively. The ECOG performance status ≥ 2 (hazard ratio [HR]: 4.1; p = .001) and use of total body irradiation (in a myeloablative conditioning regimen; HR: 2.64; p = .005) were predictive of poor OS after multivariable analysis. The occurrence of sinusoidal obstruction syndrome/veno-occlusive disease post-transplant was associated with poor survival (p = .001).

CONCLUSION

Although the use of kinase and bcl2 inhibitors may result in a decrease in the number and need of transplants, allo-HCT remains a viable option in selected patients with high-risk CLL and good performance status.

Driving Out Chronic Lymphocytic Leukemia With CAR T Cells

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in the Western hemisphere. The recent availability of novel targeted therapies, namely Bruton's tyrosine kinase, phosphoinositide-3 kinase, and BCL-2 inhibitors, have revolutionized the treatment algorithm for CLL but have not yet resulted in cure. Advances in the field of immuno-oncology and T cell engineering brought chimeric antigen receptor (CAR) T cell therapy from the laboratory to the clinic for treatment of B cell lymphoid malignancies and has improved the disease response and survival outcomes of various types of relapsed and/or refractory B cell lymphomas. While acknowledging that there are no approved CAR T cell therapies for CLL at this time, in this comprehensive review we explore novel targets for CAR T cell therapy in CLL and highlight the promising results of CAR T cell trials reported to date. Furthermore, we shed light on future areas of development, including multitarget CAR T cell products for this disease.

Long-term follow-up of the RESONATE phase 3 trial of ibrutinib vs ofatumumab

Ibrutinib, a once-daily oral inhibitor of Bruton tyrosine kinase, has greatly improved outcomes for patients with chronic lymphocytic leukemia (CLL). The phase 3 RESONATE trial, which compared single-agent ibrutinib to ofatumumab in high-risk, relapsed patients with CLL, provided support for approval of ibrutinib in the United States and Europe. We describe long-term follow-up of patients treated in RESONATE, where continued superiority of progression-free survival (PFS) (hazard ratio [HR], 0.133; 95% confidence interval [CI], 0.099-0.178) was observed. Overall survival benefit continues (HR, 0.591; 95% CI, 0.378-0.926), although with decreased magnitude relative to that seen before crossover to ibrutinib was implemented for patients on ofatumumab (HR, 0.426; 95% CI, 0.220-0.823). Notably, overall response to ibrutinib increased over time, with 91% of patients attaining a response. The PFS benefit with ibrutinib was independent of baseline risk factors, although patients with ≥2 prior therapies had shorter PFS than those with <2 prior therapies, and the presence of TP53 or SF3B1 mutations showed a trend toward shorter PFS vs without these factors. Median duration of ibrutinib was 41 months, with 46% remaining on treatment at a median follow-up of 44 months. Grade ≥3 adverse events generally decreased over time, causing only a small proportion of patients to cease therapy. Ibrutinib was discontinued due to progressive disease in 27% of patients. This long-term study provides support for sustained efficacy and safety of ibrutinib in relapsed/refractory CLL and consideration of study provisions that allow crossover to investigational therapy when benefit has been clearly demonstrated. This trial was registered at www.clinicaltrials.gov as #NCT01578707.

Association between immunoglobulin heavy-chain variable region mutational status and isolated favorable baseline genomic aberrations in chronic lymphocytic leukemia

Immunoglobulin heavy-chain variable region (IGHV) mutational status and karyotype abnormalities are important prognostic factors in chronic lymphocytic leukemia (CLL). The goal was to assess the impact of IGHV in CLL patients with isolated favorable genetic aberrations (del13q, trisomy 12, or negative fluorescence in situ hybridization [FISH]). We studied 273 CLL patients with both IGHV mutational status and cytogenetic information: 145 with isolated del13q 49 with sole trisomy 12 and 79 with negative FISH. After a median follow-up of 7.8 years, patients with del13q-unmutated IGHV had a shorter time to first treatment (TFT) (2.98 vs. 17.44 years; p < .001) and shorter overall survival (10.45 years vs. not reached; p = .0026). Patients with negative FISH-unmutated IGHV had shorter TFT (p = .02) (3.10 vs. 9.75 years, p = .053). IGHV status did not influence clinical outcomes in trisomy 12 CLL. In conclusion, IGHV mutational status shows prognostic impact in CLL patients with good prognosis genomic features.

Using prognostic models in CLL to personalize approach to clinical care: Are we there yet?

Four decades ago, two staging systems were developed to help stratify CLL into different prognostic categories. These systems, the Rai and the Binet staging, depended entirely on abnormal exam findings and evidence of anemia and thrombocytopenia. Better understanding of biologic, genetic, and molecular characteristics of CLL have contributed to better appreciating its clinical heterogeneity. New prognostic models, the GCLLSG prognostic index and the CLL-IPI, emerged. They incorporate biologic and genetic information related to CLL and are capable of predicting survival outcomes and cases anticipated to need therapy earlier in the disease course. Accordingly, these newer models are helping develop better informed surveillance strategies and ultimately tailor treatment intensity according to presence (or lack thereof) of certain prognostic markers. This represents a step towards personalizing care of CLL patients. We anticipate that as more prognostic factors continue to be identified, the GCLLSG prognostic index and CLL-IPI models will undergo further revisions.

Treatment of Del17p and/or aberrant TP53 chronic lymphocytic leukemia in the era of novel therapies

More effective therapies are emerging, with better toxicity profiles, and are being incorporated into modern treatment algorithms of chronic lymphocytic leukemia at various stages of the disease, including for patients harboring Del17p and/or aberrant TP53. Ibrutinib, an inhibitor of Bruton's tyrosine kinase, has demonstrated impressive response rates in the relapsed/refractory setting, including in the setting of Del17p and/or TP53 mutations. Venetoclax, an inhibitor of BCL-2 known to play an important role in regulating cell death, has been approved recently for treatment of patients with chronic lymphocytic leukemia with Del17p who have received at least one prior therapy. Unfortunately, a cure remains unattainable unless eligible patients are offered an allogeneic hematopoietic cell transplant. However, hematopoietic cell allografting is limited by the availability of suitable donors and significant morbidity and mortality. Recent clinical practice recommendations by the American Society for Blood and Marrow Transplantation have relegated the role of transplantation to later stages of the disease. In patients with evidence of Richter syndrome, frontline consolidation allogeneic hematopoietic cell transplantation remains the most desirable approach owing to the limited activity of ibrutinib or other novel therapies. Further therapeutic advances would require enrolling these patients in large clinical trials that evaluate novel therapies alone or in combination with traditional chemotherapies or even in the setting of posttransplant consolidation/maintenance.

Specificity and biologic activities of novel anti-membrane IgM antibodies

The concept that the B-cell Receptor (BCR) initiates a driver pathway in lymphoma-leukemia has been clinically validated. Previously described unique BCR Ig-class-specific sequences (proximal domains (PDs)), are not expressed in serum Ig (sIg). As a consequence of sequence and structural differences in the membrane IgM (mIgM) µ-Constant Domain 4, additional epitopes distinguish mIgM from sIgM. mAbs generated to linear and conformational epitopes, restricted to mIgM and not reacting with sIgM, were generated despite the relative hydrophobicity of the PDm sequence. Anti-PD mAbs (mAb1, mAb2, and mAb3) internalize mIgM. Anti-mIgM mAb4, which recognizes a distinct non-ligand binding site epitope, mediates mIgM internalization, and in low-density cultures, growth inhibition, anti-clonogenic activity, and apoptosis. We show that mAb-mediated mIgM internalization generally does not interrupt BCR-directed cell growth, however, mAb4 binding to a non-ligand binding site in the mIgM PDm-μC4 domain induces both mIgM internalization and anti-tumor effects. BCR micro-clustering in many B-cell leukemia and lymphoma lines is demonstrated by SEM micrographs using these new mAb reagents. mAb4 is a clinical candidate as a mediator of inhibition of the BCR signaling pathway. As these agents do not bind to non-mIgM B-cells, nor cross-react to non-lymphatic tissues, they may spare B-cell/normal tissue destruction as mAb-drug conjugates.

Clinical Practice Recommendations for Use of Allogeneic Hematopoietic Cell Transplantation in Chronic Lymphocytic Leukemia on Behalf of the Guidelines Committee of the American Society for Blood and Marrow Transplantation

We sought to establish clinical practice recommendations to redefine the role of allogeneic hematopoietic cell transplantation (allo-HCT) for patients with chronic lymphocytic leukemia (CLL) in an era of highly active targeted therapies. We performed a systematic review to identify prospective randomized controlled trials comparing allo-HCT against novel therapies for treatment of CLL at various disease stages. In the absence of such data, we invited physicians with expertise in allo-HCT and/or CLL to participate in developing these recommendations. We followed the Grading of Recommendations Assessment, Development and Evaluation methodology. For standard-risk CLL we recommend allo-HCT in the absence of response or if there is evidence of disease progression after B cell receptor (BCR) inhibitors. For high-risk CLL an allo-HCT is recommended after failing 2 lines of therapy and showing an objective response to BCR inhibitors or to a clinical trial. It is also recommended for patients who fail to show an objective response or progress after BCR inhibitors and receive BCL-2 inhibitors, regardless of whether an objective response is achieved. For Richter transformation, we recommend allo-HCT upon demonstration of an objective response to anthracycline-based chemotherapy. A reduced-intensity conditioning regimen is recommended whenever indicated. These recommendations highlight the rapidly changing treatment landscape of CLL. Newer therapies have disrupted prior paradigms, and allo-HCT is now relegated to later stages of relapsed or refractory CLL.

Predictors of outcome in reduced intensity allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia: summarizing the evidence and highlighting the limitations

Several studies have reported the prognostic significance of various clinical, genetic, biologic and molecular markers on postallogeneic hematopoietic cell transplantation outcomes such as nonrelapse mortality, relapse and survival. Notwithstanding limitations, existence of refractory/progressive disease at allografting yields worse nonrelapse mortality, more relapse and inferior overall survival. Advanced age results in higher nonrelapse mortality and increased relapse risk. Presence of poor-risk cytogenetics increases post-transplant relapse risk, but its impact on overall survival appears controversial. Developing prognostic models using large multicenter data could help better understand the effect of these and other variables on post-transplant outcomes. Newly discovered mutations as well as response (or not) to new potent therapies, such as ibrutinib or others, would likely be incorporated in such models.

Role of allogeneic transplantation in patients with chronic lymphocytic leukemia in the era of novel therapies: a review

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia and is characterized by a highly variable clinical course. In the past decade, several prognostic risk factors have been identified facilitating the classification of CLL into various risk groups. Patients with poor risk disease, such as poor cytogenetics or relapsing after purine-based analogues, had limited therapeutic options, with allogeneic hematopoietic cell transplantation (allo-SCT) the only known therapy with curative potential. More recently, the introduction of novel agents inhibiting the B-cell receptor pathway, and the early success with chimeric antigen receptor T cells offers an effective and relatively safe option for this poor prognostic group which holds promise in the future. Alternatively, the use of reduced intensity conditioning regimens in the allo-SCT setting has led to a significant decrease in nonrelapse mortality to 16-23%, making it an attractive therapeutic option. No recent guidelines have been developed since these novel therapies became available regarding the optimal time to allo-SCT in this patient population. The advent of these novel and highly active therapeutic agents, therefore, warrants a reappraisal of the role and timing of allo-SCT in patients with CLL. In this article, we summarize the literature regarding the novel therapeutic agents available today as well as focus on the efficacy and safety of allo-SCT.

Genomic aberrations deletion 11q and deletion 17p independently predict for worse progression-free and overall survival after allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia

Chronic lymphocytic leukemia remains incurable despite availability of potent chemoimmunotherapy regimens. Allogeneic hematopoietic cell transplantation (HCT) is the only modality that offers the possibility of cure. To identify predictors of progression-free and overall survival, we evaluated outcomes of 43 consecutive patients who received an allograft for advanced CLL. The majority received a reduced intensity conditioning regimen (n=37). Donors were HLA matched-related (n=18), matched-unrelated (n=15), mismatched-unrelated (n=7), or umbilical cord blood (n=3). The median progression-free (PFS) and overall survival (OS) were 31.4 months and 46.4 months respectively. Twenty (46.5%) patients were alive and in complete remission at a median follow-up of 31.4 months. NRM was higher than previously published series for CLL, likely due to a high burden of comorbidity (22 patients with HCT-CI ≥ 2) and a high proportion receiving HLA mismatched-unrelated donor or umbilical cord blood cells. Presence of del (11q), del(17p), or progressive disease at HCT are independent predictors of worse PFS and OS. New strategies are needed to improve survival outcomes in CLL associated with poor risk cytogenetics.

Immunotherapy for chronic lymphocytic leukemia in the era of BTK inhibitors

Understanding the pathogenesis of CLL has uncovered a plethora of novel targets for human application of monoclonal antibodies, engineered T cells, or inhibitors of signal transduction pathways. The B-cell receptor signaling pathway is being actively explored as a therapeutic target in CLL. Ibrutinib, an inhibitor of Bruton's tyrosine kinase is showing impressive responses in heavily pre-treated high-risk CLL, whether alone or in combination with MoAbs or chemotherapy. Other key components of the BCR pathway, namely PI3K-δ, are also being targeted with novel therapies with promising results as well. Future trials would likely evaluate ibrutinib in the front-line setting. Moreover, improvements in allogeneic HCT mostly by continuing to reduce associated toxicity as well as incorporating cellular therapies such as autologous CLL tumor vaccines, among others, will continue to expand. This is also the case for the next generation of chimeric antigen receptor therapy for CLL once genetically modified T cells are available at broad scale and with improved efficacy. As our ability to further refine and integrate these therapies continues to improve, and we gain further knowledge from gene sequencing, we anticipate that treatment algorithms will continue to be revised to a more personalized approach to treat this disease with improved efficacy and devoid of unnecessary toxicity.

Characterization of a new chronic lymphocytic leukemia cell line for mechanistic in vitro and in vivo studies relevant to disease

Studies of chronic lymphocytic leukemia (CLL) have yielded substantial progress, however a lack of immortalized cell lines representative of the primary disease has hampered a full understanding of disease pathogenesis and development of new treatments. Here we describe a novel CLL cell line (OSU-CLL) generated by EBV transformation, which displays a similar cytogenetic and immunophenotype observed in the patient’s CLL (CD5 positive with trisomy 12 and 19). A companion cell line was also generated from the same patient (OSU-NB). This cell line lacked typical CLL characteristics, and is likely derived from the patient’s normal B cells. In vitro migration assays demonstrated that OSU-CLL exhibits migratory properties similar to primary CLL cells whereas OSU-NB has significantly reduced ability to migrate spontaneously or towards chemokine. Microarray analysis demonstrated distinct gene expression patterns in the two cell lines, including genes on chromosomes 12 and 19, which is consistent with the cytogenetic profile in this cell line. Finally, OSU-CLL was readily transplantable into NOG mice, producing uniform engraftment by three weeks with leukemic cells detectable in the peripheral blood spleen and bone marrow. These studies describe a new CLL cell line that extends currently available models to study gene function in this disease.

Downregulation of IL-17-producing T cells is associated with regulatory T cell expansion and disease progression in chronic lymphocytic leukemia

Little is known about the immunobiology of interleukin-17 (IL-17)-producing T cells and regulatory T cells (Treg) in chronic lymphocytic leukemia (CLL). In this study, the frequencies of Th17, Tc17, and CD39(+) Treg cells were enumerated in peripheral T cells isolated from 40 CLL patients and 15 normal subjects by flow cytometry. Our results showed a lower frequency of Th17 and Tc17 cells in progressive (0.99 ± 0.12 % of total CD3(+)CD4(+) cells; 0.44 ± 0.09 % of total CD8(+) cells) compared to indolent patients (1.57 ± 0.24 %, p = 0.042; 0.82 ± 0.2 %, p = 0.09) and normal subjects (1.78 ± 0.2 %, p = 0.003; 0.71 ± 0.09 %, p = 0.04). Decrease in IL-17-producing T cells was associated with CD39(+) Treg cells expansion. Variation of IL-17-producing cells and Treg cells in indolent and progressive patients was neither associated to the expression levels of Th1- and Th2-specific transcription factors T-bet and GATA-3 nor to the frequencies of IFN-γ and IL-4-producing CD4(+) T cells in a selected number of samples. Additionally, suppressive potential of CD4(+) Treg was similar in CLL patients and normal subjects. Our data indicate that progression of CLL is associated with downregulation of IL-17-producing T cells and expansion of Treg cells, implying contribution of these subsets of T cells in the progression of CLL.

The importance of IGHV mutational status in del(11q) and del(17p) chronic lymphocytic leukemia

BACKGROUND

Most patients with CLL with a poor-risk cytogenetic profile have an unmutated IGHV sequence. Limited clinical information exists for patients with CLL who have a poor-risk cytogenetic profile and a mutated or good-risk IGHV status. We retrospectively screened all patients with CLL seen at our institution from 2006 onward who harbored a del(11q) or del(17p) CLL detected by fluorescence in situ hybridization (FISH) analysis for whom an IGHV analysis was requested. In 66 evaluable patients, 50 (76%) had an unmutated IGHV sequence. Thirty-nine patients (59%) had del(11q) and 27 patients (41%) had del(17p); no patient in this series had both del(11q) and del(17p). The patients' initial clinical presentations were similar in both mutational groups. Patients with an unmutated IGHV sequence were more likely to receive treatment and to have a shorter survival, with an estimated 3-year overall survival (OS) of 81% compared with 100% in the group with a mutated IGHV sequence (log rank, P = .06). These data suggest that IGHV mutational status has prognostic relevance even in patients with CLL who are defined as poor risk by genomic FISH analysis.

Hematopoietic Stem Cell Allografting for Chronic Lymphocytic Leukemia: A Focus on Reduced-Intensity Conditioning Regimens

Background

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only known treatment modality that currently offers a potential cure to patients with chronic lymphocytic leukemia (CLL). A better understanding of the role of adoptive immunotherapy and its consequent bona fide graft-vs-leukemia (GVL) effect has resulted in a reduction of the ablative intensity and toxicity of preparative allo-HCT regimens.

Methods

The authors review the published data of reduced-intensity conditioning (RIC) allo-HCT in patients with CLL.

Results

RIC allo-HCT has reduced the transplant associated morbidity and mortality of the procedure and has consequently broadened applicability of allo-HCT to patients with CLL who are generally of more advanced age (> 60 years) and who often have associated comorbidities.

Conclusions

Published literature supports the use of RIC allo-HCT for these patients once a suitable donor is identified, provided they fulfill acceptable consensus criteria for hematopoietic stem cell allografting. Several studies have shown that T-cell-replete RIC allo-HCT is also capable of overcoming the adverse effect of poor prognostic factors in CLL such as del(17p), unmutated IgVH, or ZAP-70 expression. Continued clinical trials to identify the optimal regimen for RIC allo-HCT for patients with CLL are warranted.

Importance of immunoglobulin heavy chain variable region mutational status in del(13q) chronic lymphocytic leukemia

Among prognostic factors for chronic lymphocytic leukemia (CLL), immunoglobulin heavy chain variable region (IGHV) mutation status and DNA analysis appear to be the most important. However, there is limited clinical outcome information for patients with the favorable-risk del(13q) and poor-risk unmutated IGHV. We retrospectively screened all patients with CLL at our institution between 2004 and June 2010 for del(13q) who also had an IGHV analysis. Unmutated IGHV was found in 38/79 patients; age, Rai stage, prior therapy, and time to evaluation were similar to those for patients with mutated IGHV. Unmutated patients were nearly four times more likely to harbor additional chromosomal aberrations compared to mutated patients (p < 0.001). During a median follow-up of 4.5 years, unmutated patients were more likely to demonstrate Rai stage progression (69% vs. 31%, log-rank p < 0.001) and to receive treatment (5-year cumulative probability of treatment: 65% vs. 32%, p < 0.001). Patients with unmutated CLL also had a shorter overall survival (5-year survival probability: 72% vs. 100%, p < 0.001). When limiting analysis to the 47 patients with del(13q) as a sole chromosomal abnormality, the 13 (28%) unmutated patients were more likely to demonstrate Rai progression (p < 0.001), to receive treatment (p = 0.02), and to have a shorter overall survival (p = 0.13) than the 34 mutated patients. These data suggest that del(13q) conveys an indolent course only in patients with IGHV-mutated CLL.

Cyclic nucleotide phosphodiesterase 7B mRNA: an unfavorable characteristic in chronic lymphocytic leukemia

A cost- and time-efficient means to define the prognosis of patients with chronic lymphocytic leukemia (CLL) is desirable but does not yet exist. On the basis of the evidence that CLL cells have enhanced expression of the cyclic nucleotide phosphodiesterase isoform 7B (PDE7B), we hypothesized that PDE7B expression might provide such information. We assessed PDE7B mRNA expression using quantitative real-time PCR in peripheral blood mononuclear cells isolated from 85 patients and 30 normal subjects. We compared PDE7B mRNA expression with that of other disease features to determine if its expression correlates with the prognosis of patients with CLL. We found that CLL patients with PDE7B mRNA levels in the top quartile (greater than ninefold elevation relative to normal controls) have a several-year shorter median time-to-treatment (TTT, 36 months) compared to that of patients whose CLL cells express lower levels of PDE7B mRNA (TTT, 77 months, p=0.001). High PDE7B mRNA expression correlates with expression of zeta-chain-associated protein kinase 70 (ZAP-70), unmutated immunoglobulin heavy chain variable (IGHV) region genes and β2 microglobulin (β2M), but use of a multivariate Cox model revealed that high PDE7B mRNA expression independently predicts a short TTT, even after adjusting for several other disease characteristics (ZAP-70 or CD38 expression, IGHV mutation status and Rai status). High expression of PDE7B is an unfavorable characteristic in CLL. Assessment of PDE7B mRNA expression thus appears to be a clinically useful biomarker to define the prognosis of patients with CLL.

Chronic lymphocytic leukemia: putting new treatment options into perspective

Chronic lymphocytic leukemia (CLL) is a monoclonal B-cell malignancy that afflicts mainly older individuals. Since many patients are diagnosed in the earliest stages, the course of the disease may be indolent and asymptomatic, requiring no therapy. For those who are diagnosed in advanced stages or whose disease becomes symptomatic, treatment is indicated. Advances in identifying prognostic factors, such as cytogenetics, IgHV mutational status, CD38, TP53, and ZAP-70, are helping physicians better predict who is more likely to have progressive disease and thus needs more frequent monitoring. Some of these prognostic factors are also helping to guide therapy choices as they can predict response to treatment and/or duration of response. Recent advances in treatment options have moved beyond traditional management with alkylating agents and purine analogs into regimens combining these two chemotherapy classes with monoclonal antibodies targeting CD20. Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) has become the most effective therapy option to date for CLL. Compared with fludarabine and cyclophosphamide, FCR has shown higher complete response rates and longer progression-free survival. Bendamustine, a unique alkylating agent with purine analog properties, has recently been approved by the FDA for treatment of CLL and provides a new alternative to existing therapies. Initial trials combining bendamustine with rituximab are showing promise for both untreated and relapsed/refractory disease. Other agents recently approved and/or being tested, such as ofatumumab, flavopiridol, and lenalidomide, are demonstrating activity in the relapsed setting.

Clinical utility of molecular and flow cytometric markers in chronic lymphocytic leukaemia

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is a clinically heterogeneous disease. While immunoglobulin variable region heavy chain (IgVH) mutational status remains the 'gold standard' in molecular prognostication, a range of additional markers is increasingly being used in clinical trials. As awareness of trial data increases, requests to determine these prognostic markers for new CLL patients are becoming more prevalent in Australia.

AIM

To explore the clinical utility of currently available prognostic markers for CLL in an Australian cohort.

METHODS

IgVH mutational status and gene usage was determined and compared with other reported immunophenotypic markers, cytogenetics and clinical outcome as defined by treatment-free survival (TFS), lymphocyte doubling time and clinical stage in a cohort of 65 CLL patients.

RESULTS

An unmutated IgVH gene, high expression of CD38, ZAP-70, CD25, CD49d, CD54 or low expression of CD49c was associated with shorter TFS indicating an adverse clinical prognosis in our cohort. High expression of each of CD38, ZAP-70, CD49d and CD54 was significantly associated with an unmutated IgVH gene; however, associations were not absolute. IgVH and CD25 expression retained their significance in multivariate analysis. Concordant CD25(high) /IgVH unmutated CLL patients had the shortest median TFS interval (40 months) in our cohort.

CONCLUSIONS

Molecular and immunophenotypic markers remain useful as adjuncts to clinical prognostication; however, as single parameters they are unable to dictate the timing of therapeutic intervention. The combined use of CD25 and IgVH mutational status may be clinically relevant to CLL prognostication while also providing insight into the biological pathways involved in disease progression.