A Rare Case of Hairy Cell Leukemia with Unusual Loss of CD123 Associated with COVID-19 at the Time of Presentation

Coronavirus disease 2019 (COVID-19) pandemic has been a serious threat and has been reported with different presentations and complications. Older age, along with comorbidities such as diabetes, hypertension, or cardiac disease, increases the risk factors for COVID-19 severity and death [N Engl J Med. 2020;382(18):1708–20 and Lancet Respir Med. 2020 05;8(5):475–81]. It is proposed that cancer patients have a significantly higher incidence of severe incidents including admission to the intensive care unit, the necessity for assisted ventilation, and even death after catching the virus compared with non-cancer patients [Lancet Oncol. 2020;21(3):335–7]. It is also described that cancer patients appear to be twice as likely to contract infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) [JAMA Oncol. 2020;6(7):1108–10]. Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative disorder, with patients typically presenting with cytopenias, marked splenomegaly in 80–90% of patients, circulating leukemia cells, bone marrow infiltration and the presence of BRAF V600E somatic mutation [Indian J Hematol Blood Transfus. 2014;30(Suppl 1):413–7]. Leukemic cells classically have central nuclei and abundant cytoplasm with hairy-like projections and express CD11c, CD25, CD103, and CD123 [Indian J Hematol Blood Transfus. 2014;30(Suppl 1):413–7]. Loss of CD123 in HCL has been rarely reported in the literature [Am J Hematol. 2019;94(12):1413–22]. We describe a unique case of a COVID-19-positive male who presented with severe respiratory symptoms, deteriorated quickly, and was intubated. Workup of severe progressive pancytopenia and bone marrow examination revealed HCL without splenomegaly and with atypical unusual loss of CD123. To our knowledge, this is the first case of CD123-negative HCL without splenomegaly associated with COVID-19 infection as the initial presentation.

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Primary Hairy Cell Leukemia/Lymphoma of the Breast: A Case Report and Review of the Literature

Case Reports in Pathology ◽

10.1155/2014/497027 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Monika Pilichowska ◽

Ahmad Shariftabrizi ◽

Ian Mukand-Cerro ◽

Kenneth Miller

Keyword(s):

Bone Marrow ◽

Hairy Cell Leukemia ◽

Incidental Finding ◽

Reduction Mammoplasty ◽

Braf V600e ◽

Hairy Cell ◽

Cell Leukemia ◽

First Case ◽

Mutational Status ◽

Atypical Presentations

Hairy cell leukemia/lymphoma (HCL) is a rare B-cell neoplasm primarily involving spleen, bone marrow, and blood. However, other sites of primary involvement do occur and can present a diagnostic and therapeutic challenge. We present an unusual case of HCL involving predominantly the breast that was diagnosed as an incidental finding during an elective reduction mammoplasty in an otherwise healthy asymptomatic woman. Bone marrow performed for staging revealed limited involvement by HCL. Notably, there was no splenomegaly and/or involvement of other extramedullary sites. The peripheral blood revealed minimal involvement detected by flow cytometry. Extensive immunohistochemical studies supported by positive BRAF V600E mutational status confirmed the diagnosis of HCL. The patient remains asymptomatic without treatment one year following the diagnosis. This is the first case of a well-documented HCL presenting primarily in the breast in an asymptomatic patient. We review the literature on extramedullary, extrasplenic involvement by HCL and discuss the diagnostic challenges as well as the utility of immunohistochemistry and molecular studies in the diagnosis of atypical presentations of HCL.

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Genomics of Hairy Cell Leukemia

Journal of Clinical Oncology ◽

10.1200/jco.2016.71.1556 ◽

2017 ◽

Vol 35 (9) ◽

pp. 1002-1010 ◽

Cited By ~ 25

Author(s):

Enrico Tiacci ◽

Valentina Pettirossi ◽

Gianluca Schiavoni ◽

Brunangelo Falini

Keyword(s):

B Cell ◽

Hairy Cell Leukemia ◽

Ex Vivo ◽

Braf Inhibitor ◽

Braf V600e ◽

Leukemic Cells ◽

Splenic Marginal Zone Lymphoma ◽

Hairy Cell ◽

Cell Leukemia ◽

Purine Analogs

Hairy cell leukemia (HCL) is a chronic mature B-cell neoplasm with unique clinicopathologic features and an initial exquisite sensitivity to chemotherapy with purine analogs; however, the disease relapses, often repeatedly. The enigmatic pathogenesis of HCL was recently clarified by the discovery of its underlying genetic cause, the BRAF-V600E kinase-activating mutation, which is somatically and clonally present in almost all patients through the entire disease spectrum and clinical course. By aberrantly activating the RAF-MEK-ERK signaling pathway, BRAF-V600E shapes key biologic features of HCL, including its specific expression signature, hairy morphology, and antiapoptotic behavior. Accompanying mutations of the KLF2 transcription factor or the CDKN1B/p27 cell cycle inhibitor are recurrent in 16% of patients with HCL and likely cooperate with BRAF-V600E in HCL pathogenesis. Conversely, BRAF-V600E is absent in other B-cell neoplasms, including mimickers of HCL that require different treatments (eg, HCL-variant and splenic marginal zone lymphoma). Thus, testing for BRAF-V600E allows for a genetics-based differential diagnosis between HCL and HCL-like tumors, even noninvasively in routine blood samples. BRAF-V600E also represents a new therapeutic target. Patients’ leukemic cells exposed ex vivo to BRAF inhibitors are spoiled of their HCL identity and then undergo apoptosis. In clinical trials of patients with HCL who have experienced multiple relapses after purine analogs or who are refractory to purine analogs, a short course of the oral BRAF inhibitor vemurafenib produced an almost 100% response rate, including complete remission rates of 35% to 42%, without myelotoxicity. To further improve on these results, it will be important to clarify the mechanisms of incomplete leukemic cell eradication by vemurafenib and to explore chemotherapy-free combinations of a BRAF inhibitor with other targeted agents (eg, a MEK inhibitor and/or an anti-CD20 monoclonal antibody).

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Evaluation of BRAFV600E, NRAS and KRAS Mutations As Well As IGHV Usage for Diagnostic Use in Hairy Cell Leukemia, Hairy Cell Leukemia-Variant and Splenic Marginal Zone Lymphoma.

Blood ◽

10.1182/blood.v120.21.2679.2679 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2679-2679

Author(s):

Susanne Schnittger ◽

Frank Dicker ◽

Christiane Eder ◽

Sabine Jeromin ◽

Tamara Alpermann ◽

...

Keyword(s):

Flow Cytometry ◽

Hairy Cell Leukemia ◽

Braf V600e Mutation ◽

Braf V600e ◽

Leukemic Cells ◽

Multiparameter Flow Cytometry ◽

Splenic Marginal Zone Lymphoma ◽

Hairy Cell ◽

Cell Leukemia ◽

Equity Ownership

Abstract Abstract 2679 Background: The BRAF V600E mutation has recently been discovered in nearly all cases of hairy cell leukemia (HCL), but not in cases of HCL-variant (HCL-v). However, this perfect correlation has been challenged by studies reporting HCL cases without BRAF V600E. Interestingly, the immunoglobulin heavy chain variable region gene IGHV4–34, which has been associated with poor prognosis in HCL, appeared exclusively and to a high percentage in these BRAF V600E-negative cases of classic HCL and also in HCL-v (Xi et al., Blood, 2011). Further, splenic marginal zone lymphoma (SMZL) is a disease closely related to HCL and HCL-v and BRAF has been shown to be unmutated in this entity. Aims: 1. To characterize our cohorts of HCL, HCL-v and SMZL for the presence of BRAF V600E and to correlate the results with IGHV gene usage. 2. We hypothesized that other genes of the RAF/RAS pathway might be affected. Thus we analysed NRAS, and KRAS in addition to BRAF for mutations in all three entities. Methods: We analyzed the bone marrow or peripheral blood of 314 cases (182 cases with HCL, 49 cases with HCL-v, and 83 cases with SMZL) at diagnosis as confirmed by multiparameter flow cytometry and cytomorphology. The BRAF V600E mutation was analyzed by an mRNA-based reverse transcription allele-specific real-time quantification (RQ-PCR) assay. The BRAF V600E expression was calculated as %BRAF V600E/BRAF wt. NRAS and KRAS were analyzed by melting curve analysis and subsequent Sanger sequencing. IGHV genes and mutation status were analyzed by the use of Biomed-2 primers. An identity of ≥98% of the analyzed IGHV sequence compared to published germline sequences was considered an unmutated IGHV status. Results: In our cohort the median percent leukemic cells was 16% (range 0.2–74%) for HCL, 33% (range 5–59%) for HCL-v and 29% (range: 1–84%) for SMZL as determined by multiparameter flow cytometry. The BRAF V600E mutation was detected in 178/182 (97.8%) of HCL cases, whereas 0/49 of HCL-v and 0/83 SMZL were positive. Thus, the BRAF V600E mutation is 100% specific for HCL regarding these three entities. The median BRAF V600E expression ratio of positive cases was 14.2 (range 0.22 – 280.3). After normalization to % pathological cells as assessed by multiparameter flow cytometry the median ratio was 173 (range:22–1,788). However, in 4 cases with 4%, 8%, 28% and 66% percent leukemic cells by multiparameter flow cytometry, which is within the clone size that can be clearly detected by the BRAF V600E-specific RQ-PCR assay, no mutation was detected. Thus, BRAF V600E detection used for the identification of HCL has a sensitivity of 97.8%. Further, NRAS and KRAS mutation screening in all cases with HCL, HCL-v, and SMZL did not detect any mutation except for one case with SMZL that harboured an NRAS Gly12Asp mutation. This case was found to have an MDS in parallel and thus the mutation more likely belongs to the MDS clone. Thus, analysis of NRAS and KRAS mutations does not further improve diagnostics in these diseases. Further, we analyzed the IGHV usage in all 4 BRAF unmutated HCL and in additional 60 cases (total n=64) with HCL and 41 cases with HCL-v. IGHV4–34 usage was very frequent in HCL-v with 14/41 (34.1%). In contrast, it was never detected in HCL including the BRAF wildtype cases. Thus, we were not able to confirm the usage of the IGHV4–34 gene, which was previously suggested for BRAF V600E negative HCL. On the other hand IGHV5–51 was most frequently found in HCL (9/64, 14.1%) but never detected in HCL-v. We detected an unmutated IGHV status in 12/62 (19.4%) of HCL, which was less frequent compared to 14/40 (35.0%) in HCL-v (p = 0.095). The IGHV mutation status was unmutated in 9/11 (81.8%) IGHV4–34 cases (100% identity to germline each). The four cases of HCL, which lacked BRAF V600E mutation, expressed the IGHV genes IGHV1–3*01 (96.5% identity), IGHV1–69*02 (94.0% identity), IGHV3–9*01 (96.9% identity) and IGHV6-1*01 (99.0% identity), which were also expressed by various BRAF V600E positive HCL cases in our cohort. Conclusions: 1) In our cohort of 314 cases with HCL, HCL-v, and SMZL we confirm a high specificity (100%) and sensitivity (97.8%) for BRAF V600E mutations to detect HCL. 2) Other RAS pathway mutations (NRAS, KRAS) were not detected in any of the three analysed entities. 3) In the 4 rare cases of HCL with BRAF wt we were not able to confirm the previously postulated IGHV4–34 usage. 4) IGHV4–34 further delineates classic HCL from HCL-v. Disclosures: Schnittger: MLL Munich Leukemia Laboratory: Equity Ownership. Dicker:MLL Munich Leukemia Laboratory: Employment. Eder:MLL Munich Leukemia Laboratory: Employment. Jeromin:MLL Munich Leukemia Laboratory: Employment. Alpermann:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Equity Ownership.

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Resolution of Hairy Cell Leukemia Minimal Residual Disease by Both BRAF and Clone-Specific Real-Time Quantitative PCR (RQ-PCR) After Treatment with Moxetumomab Pasudotox.

Blood ◽

10.1182/blood.v120.21.2896.2896 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2896-2896 ◽

Cited By ~ 1

Author(s):

Robert J. Kreitman ◽

Evgeny Arons ◽

Sapolsky Jeffrey ◽

Laura Roth ◽

Hong Zhou ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Hairy Cell Leukemia ◽

Residual Disease ◽

Braf V600e Mutation ◽

Braf V600e ◽

Hairy Cell ◽

Cell Leukemia ◽

Specific Primer ◽

Minimal Residual

Abstract Abstract 2896 Background: Moxetumomab pasudotox is an anti-CD22 recombinant immunotoxin containing truncated Pseudomonas exotoxin which was recently reported to achieve a complete remission rate of 46% in 28 patients with relapsed/refractory hairy cell leukemia (HCL). An additional 20 patients were treated at the highest dose level and are now fully evaluable for response and minimal residual disease (MRD) determinations. RQ-PCR using clone-specific primers and a clone-specific TaqMan probe is capable of detecting one HCL cell in 106normal cells. Recently reported methods to detect the HCL-associated BRAF V600E mutation include pyrosequencing (5–10% sensitivity) and PCR (0.1–0.23% sensitivity). Methods: Moxetumomab pasudotox was administered to 16 patients at 5–40 ug/Kg every other day for 3 doses (QODx3) and to 32 patients at 50 ug/Kg QODx3, via 1–16 (median 4) cycles per patient at 4-week intervals. Complete remission (CR) required resolution of cytopenias and elimination of HCL in the blood and marrow by standard microscopy, but MRD could be present by flow cytometry of blood or bone marrow aspirate (BMA) or immunohistochemistry (IHC) of the bone marrow biopsy (BMBx). Blood and marrow from patients were also tested by PCR using consensus primers. When immunoglobulin (Ig) rearrangements could be cloned, RQ-PCR using clone-specific primer and probe was performed. To detect MRD by the BRAF V600E mutation, BRAF quantitative PCR (BRAF-qPCR) was performed on cDNA samples, using mutant-specific primer, and SYBR-Green detection followed by melting point analysis. MRD testing for BRAF-qPCR, unlike clone-specific RQ-PCR, did not require prior cloning of the Ig rearrangement. Results: All 198 cycles of moxetumomab administered to 48 patients were evaluable for toxicity and response. No dose limiting toxicity was observed, although 2 patients as previously reported had a grade 2 hemolytic uremic syndrome with transient grade 1 platelet and creatinine abnormalities. Of the 48 HCL patients at all dose levels, there were 26 (54%) CRs, with an overall response rate (ORR) of 88%. Of 32 at 50 ug/Kg QODx3, there were 19 (59%) CRs with an ORR of 91%. Of these 19 CRs, 11 (58%) achieved MRD negativity by repeated flow cytometry of both BMA and blood and IHC of BMBx. Flow cytometry of the BMA was the most sensitive conventional test of MRD. Of the 9 CRs at 50 ug/Kg QODx3 evaluable by clone-specific RQ-PCR of blood, 5 negative were also flow-negative, and 4 positive were also flow-positive (p=0.008). BRAF-qPCR on cDNA from limiting dilutions of BRAF V600E+ Colo-205 cells into BRAF wild-type cells achieved consistent detection at 1:105dilution (0.001%). Of 10 flow-negative CRs at 50 ug/Kg QODx3 evaluated by BRAF-qPCR, all 10 (100%) were BRAF-qPCR negative, including 4 which were nonevaluable by RQ-PCR due to inability to clone the Ig rearrangements prior to treatment. Currently 12 (63%) of the 19 CRs at 50 ug/Kg QODx3 are ongoing at 6–47 (median 21) months, including 10 (91%) of 11 MRD-negative vs 2 (25%) of 8 MRD+ CRs (p=0.006). Conclusions: Moxetumomab pasudotox is active in relapsed and refractory HCL and has a safety profile supporting further development for this disease. Retreatment on this trial could not necessarily be extended to achieve MRD-negative BMAs or molecular remission by RQ-PCR using sequence-specific or BRAF primers. However, these tests might be useful in the future to guide retreatment, optimize CR durability and possibly eradicate the HCL clone in selected patients. This summary contains investigator reported data. This study was sponsored by MedImmune, LLC, and supported by NCI's Intramural Research Program and the Hairy Cell Leukemia Research Foundation. Disclosures: Kreitman: NIH: Co-inventor on the NIH patent for Moxetumomab Pasudotox, Co-inventor on the NIH patent for Moxetumomab Pasudotox Patents & Royalties. Off Label Use: Moxetumomab Pasudotox is an experimental agent for CD22+ hematologic malignancies. FitzGerald:NIH: Coinventor on the NIH patent for Moxetumomab Pasudotox, Coinventor on the NIH patent for Moxetumomab Pasudotox Patents & Royalties. Fei:AstraZeneca: Stock, Stock Other; MedImmune, LLC: Employment. Ibrahim:AstraZeneca: Stocks, Stocks Other; MedImmune: Employment. Pastan:NIH: Coinventor on NIH patent for moxetumomab pasudotox, Coinventor on NIH patent for moxetumomab pasudotox Patents & Royalties.

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Increased Expression of Myc in Hairy Cell Leukemia, and Cell-Sensitivity to JQ1

Blood ◽

10.1182/blood.v128.22.5112.5112 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5112-5112

Author(s):

Evgeny Arons ◽

Hong Zhou ◽

Yonghong Wang ◽

Daniel Edelman ◽

Robert J. Kreitman ◽

...

Keyword(s):

B Cell ◽

Hairy Cell Leukemia ◽

Poor Prognosis ◽

Braf V600e ◽

Leukemic Cells ◽

Annexin A1 ◽

Expression Data ◽

Hairy Cell ◽

Cell Leukemia ◽

Wild Type

Abstract Classic hairy cell leukemia (HCL), comprising 2% of leukemias, is an indolent B-cell malignancy with malignant lymphocytes expressing B-cell antigens CD20 and CD22, CD103, CD11c, CD25, Annexin A1, BRAF V600E mutation, and monoclonal immunoglobulin (Ig) rearrangement. HCL variant (HCLv), which is ~10% as common as HCL, has much poorer response to therapy and more aggressive course, lacks CD25 and Annexin A1, and is wild-type for BRAF. HCLv is considered separate from HCL by the World Health Organization in the unclassifiable splenic B-cell leukemia/lymphomas. Another poor-prognosis group overlaps HCL and HCLv in which unmutated IGHV4-34 Ig rearrangement is expressed. IGHV4-34+ leukemic cells can resemble classic HCL with CD25 and Annexin A1 expression, but are BRAF wild-type. No uniform mutation has been identified for HCLv and IGHV4-34+ HCL, although MAP2K1 (MEK1) mutations have recently been identified in half of cases. Thus HCLv and IGHV4-34+ HCL are less indolent leukemias with few therapy options and no known molecular target. To study HCLv and IGHV4-34+ HCL, leukemic samples were purified by negative B-cell isolation followed by positive CD11c sorting. Following extraction (Qiagene, AllPrep DNA/RNA Kit), RNA samples from patients were analyzed in microarray studies (Human HT-12 v4 BeadChips, Illumina, Inc.). Expression data were compared by unpaired nonparametric analysis using Mann-Whitney. MYC expression using one probe (log2 values, mean +/- standard deviation) was 7.30 +/- 1.51 for 37 HCL vs 9.77 +/- 1.15 for 32 HCLv or IGHV4-34+ HCL (2-sided p<0.0001). For the other probe, expression was 7.07 +/- 1.51 vs 9.44 +/- 1.17 (p<0.0001). Expression data for MYC had previously been submitted for 31 chronic lymphocytic leukemia (CLL) and 16 HCL samples (Dataset GSE2350, Basso et al, Nat Genet, 37:382, 2005). By 1 probe for MYC, expression was 8.07 +/- 0.55 for CLL vs 9.31 +/- 1.19 for HCL (p=0.0023). By another MYC probe, expression was 9.28 +/- 0.47 for CLL vs 10.22 +/- 0.98 for HCL (p=0.0032). To investigate potential therapeutic relevance of aberrant MYC expression in HCL, HCLv and IGHV4-34+ HCL, the bromodomain and extra terminal (BET) protein inhibitor JQ1, which has been associated with down-regulation of c-Myc via Brd4, was incubated with primary leukemic cells and ATP incorporation was measured. JQ1 inhibited 12 samples of HCL (IC50s 214 +/- 217 nM) more potently than 14 samples of CLL (IC50s 1.77uM +/-2.62 uM, p=0.020), and also inhibited 14 samples of HCLv or IGHV4-34+ HCL (IC50s 221 +/- 234 nM) more potently than the 14 CLL samples (p=0.0079). However, JQ1 inhibition was similar comparing HCL and HCLv or IGHV4-34+ HCL (p=0.89). To exclude non-specific inhibition of the cells, the inactive control molecule JQ1R was tested and was only 6.0% +/- 4.0% as active as JQ1 toward HCL or HCLv or IGHV4-34+ HCL samples. Normal peripheral blood mononuclear cells were resistant (IC50 > 20 uM). In conclusion, our results show that MYC expression is higher in HCLv and IGHV4-34+ HCL than in classic HCL and higher in classic HCL than CLL. Moreover, JQ1 inhibits HCL or its variants more potently than CLL, although the inhibition assay used does not detect a difference between the variants and classic HCL. Further experiments with other inhibitors will be needed to determine if the increased expression of MYC in HCL and its poor-prognosis variants can be exploited for treatment. Disclosures No relevant conflicts of interest to declare.

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Efficacy and Safety of the BRAF Inhibitor Vemurafenib in Hairy Cell Leukemia Patients Refractory to or Relapsed after Purine Analogs: A Phase-2 Italian Clinical Trial

Blood ◽

10.1182/blood.v124.21.150.150 ◽

2014 ◽

Vol 124 (21) ◽

pp. 150-150 ◽

Cited By ~ 2

Author(s):

Enrico Tiacci ◽

Luca De Carolis ◽

Pier Luigi Zinzani ◽

Alessandro Pulsoni ◽

Francesco Zaja ◽

...

Keyword(s):

Bone Marrow ◽

Hairy Cell Leukemia ◽

Braf Inhibitor ◽

Post Treatment ◽

The Other ◽

Braf V600e ◽

Morphological Evidence ◽

Hairy Cell ◽

Cell Leukemia

Abstract BACKGROUND AND AIMS: Hairy cell leukemia (HCL) is very sensitive to purine analogs (PAs), but ~40% of patients relapse and become progressively less responsive to these myelotoxic and immune-suppressive drugs. Having discovered the BRAF-V600E kinase-activating mutation as the genetic lesion underlying HCL (Tiacci et al, NEJM 2011;364:2305), we performed the first clinical trial of a BRAF inhibitor (vemurafenib) in refractory/relapsed HCL. In particular, this is a phase-2, academic, single-arm, Italian, multi-center (n=8) study (HCL-PG01; EudraCT 2011-005487-13). METHODS: In 11 months we enrolled 28 BRAF-V600E+ HCL patients, needing therapy due to cytopenias and including: i) 6 patients primary refractory to a PA; ii) 21 patients who relapsed early and/or repeatedly after PAs and had received a median of 4 previous therapies; and iii) a 81-year old patient showing severe myelotoxicicity after a PA (discouraging its further use). Previous treatments other than PAs included interferon, rituximab and splenectomy in 12, 14 and 8 patients, respectively. Complete remission (CR) required resolution of cytopenias (N≥1500/mmc, PLT≥100000/mmc, Hb≥11 g/dl), no morphological evidence of HCL cells in the bone marrow biopsy and blood smear, and no splenomegaly. Partial remission (PR) required resolution of cytopenias, and a ≥50% reduction of splenomegaly and of marrow and blood HCL involvement by immunophenotyping. Two patients were not evaluable as they went off-study after ≤1 week of treatment (due to drug-unrelated acute myocardial infarction and consent withdrawal after grade-3 drug-related reversible pancreatitis). RESULTS: Vemurafenib, given orally at the dose of 960 mg twice daily on an outpatient basis for a median of 16 weeks, was generally well tolerated. Drug-related adverse events (mainly arthralgias, skin toxicities, pancreatitis; no myelosuppression) were frequent, but reversible in all patients, and were typically grade 1-2. Only 7 patients developed grade 3 events, and none grade 4 events. Although we did not observe any cutaneous squamous cell carcinomas/keratoachantomas (as reported in BRAF-V600E+ melanoma patients treated with vemurafenib), 3 patients developed 2 basaliomas and 1 superficial melanoma, all treated with a simple excision. Notably, overall response rate was 96% (25/26 patients): 9/26 (34.6%) CRs and 16/26 (61.4%) PRs, obtained after a median of 8 and 9 weeks respectively. CR and PR patients included 1 and 5 primary refractory ones, respectively, as well as 4 and 10 not responding to the last prior treatment, respectively. In all CR patients immunohistochemistry showed minimal residual disease (≤10%) at the end of treatment. Six of 9 (67%) CR patients enjoyed normal blood counts at a median of 13 (range 12-15) months from the end of treatment (see Figure): 3 of these 6 patients showed no morphological evidence of HCL in the bone marrow biopsy (complying with a continuous CR) at 12, 13 and 15 months, respectively, whereas the other 3 lost the bone marrow CR status, all at 12 months. The remaining 3/9 CR patients (33%) developed a mild cytopenia (N ~1000/mmc or PLT ~80000/mmc) 5, 9 and 12 months post-treatment, respectively: in the 2nd patient the cytopenia remained stable until the last follow-up at 15 months, whereas in the other two cases it worsened requiring therapy 9 and 18 months post-treatment, respectively (see Figure). These two latter patients were recently retreated with vemurafenib for 12 and 4 weeks, and obtained a PR and a second CR. Among the 16 PR patients, 5 (31%) mantain normal blood counts at a median of 12 (range 8-17) months post-treatment (see Figure). The other 11 PR patients developed cytopenia(s) after 3 months of median follow-up (range 5-10): in 6 patients (38%) no anti-leukemic therapy was started at a median of 9 (range 6-12) months post-treatment, whereas in the remaining 5 cases (31%) cytopenia(s) worsened requiring therapy at a median of 8 (range 5-11) months of follow-up (see Figure). Four of these latter 5 patients were retreated with vemurafenib for 12 weeks: 3 cases had a minor response and the last one witnessed a second PR that lasted less than the first PR (3 versus 9 months). CONCLUSIONS: In heavily pre-treated HCL patients, a short oral course of vemurafenib was safe, and proved quickly and highly active. Retreatment with vemurafenib was able to reinduce remissions in patients relapsing after a CR, but was less effective in patients relapsing after a PR. Figure 1 Figure 1. Disclosures Off Label Use: Off-label use of vemurafenib in hairy cell leukemia will be discussed as part of a clinical research protocol..

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Sensitivity of refractory hairy cell leukemia to BRAF inhibition.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.6519 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. 6519-6519

Author(s):

Sascha Dietrich ◽

Nicola Lehners ◽

Jennifer Huellein ◽

Mindaugas Andrulis ◽

Michael Hundemer ◽

...

Keyword(s):

Bone Marrow ◽

Hairy Cell Leukemia ◽

Specific Inhibitor ◽

Braf V600e ◽

Bone Marrow Infiltration ◽

Driver Mutations ◽

Hairy Cell ◽

Cell Leukemia ◽

Mutant Braf

6519 Background: Thorough understanding of genetic lesions in cancer and targeted intervention against driver mutations are beginning to transform cancer treatment. An activating mutation of the BRAF serine/threonine protein kinase, BRAF V600E occurs in a proportion of malignant melanomas, and colorectal, thyroid, and other cancers. In hairy-cell leukemia (HCL), BRAF V600E is nearly always present, suggesting oncogene dependence. Methods: Here, we present a patient with HCL who was refractory to three lines of purine analogue-based treatment. The BRAF V600E mutation was demonstrated. After intensive counseling, the patient and his family provided written consent for vemurafenib (mutant BRAF-specific inhibitor) treatment. Results: Before vemurafenib treatment, the patient had subtotal bone marrow infiltration and massive splenomegaly (24.8 x 8.3 cm) leading to severe cytopenia (leukocytes 680/µl, hemoglobin 10.0 g/dl, platelets 36.000/µl). Treatment with vemurafenib was started with 240 mg twice daily and was slowly escalated to 1920 mg/d. Within two days of treatment, the spleen softened and decreased in size. Serum CD25 (sCD25) level fell rapidly from 24.800 U/ml to normal levels (<900), and platelets, hemoglobin, and leukocyte counts rose. After 16 days of vemurafenib treatment, the spleen size had shrunk to 14 x 5 cm. By day 28 of treatment (on 720 mg/d), platelet counts and sCD25 levels had normalized. Bone marrow infiltration by HCL had decreased from 70% to 20% on day 16 and complete remission was achieved on day 35. We terminated treatment on day 57 when there was no evidence of any circulating hairy cells by immunophenotyping. Conclusions: The striking therapeutic activity of vemurafenib in our patient provides the first in vivo evidence to substantiate the BRAF V600E allele as a driver and validates mutant BRAF as a therapeutic target in HCL. Proof of principle for a molecularly targeted therapy of HCL adds to the recent success of targeting oncogenic kinases in oncogene addicted malignancies. Given the rarity of HCL, introducing new therapeutic modalities may be challenging. Future studies are needed that compare short-term inhibition of BRAF with low doses of vemurafenib (or alternative BRAF inhibitors) and standard therapy.

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Down-Regulation of CD25 Antigen in Hairy Cell Leukemia Patients after Treatment

Blood ◽

10.1182/blood-2018-99-120043 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4143-4143

Author(s):

Mirela Anghelina ◽

Narendranath Epperla ◽

Kerry A. Rogers ◽

Ling Guo ◽

Qiuhong Zhao ◽

...

Keyword(s):

Bone Marrow ◽

Peripheral Blood ◽

Hairy Cell Leukemia ◽

Research Funding ◽

Leukemic Cells ◽

World Health ◽

Hairy Cell ◽

Cell Leukemia ◽

Cd25 Expression

Abstract Background: Hairy Cell Leukemia (HCL) is a rare hematological malignancy, comprising only of 2% of all leukemias, with an estimated 900 new cases diagnosed each year in the United States. HCL displays a characteristic immunophenotypic profile that include pan-B cell markers including CD103, CD11c, and CD25. World Health Organization guidelines defines two forms of HCL, classic HCL (cHCL) and variant HCL (HCLv) as two distinct clinical entities. Patients with cHCL have a distinct immunophenotypic profile on their malignant leukemic cells including CD20+, CD19+, CD11c+, CD25+, CD103+, and CD123+, while the leukemic cells from patients with HCLv show CD11c+, CD20+ and CD19+, while lacking CD25 and CD123 expression. Some patients with cHCL will retain CD25 positivity while demonstrating negativity for other typical markers, herein termed atypical HCL (aHCL). Presence or absence of CD25 is an important determinant in classifying patients into cHCL and HCLv. Although it has previously been reported that CD25 expression may be lost during treatment with the targeted agent vemurafenib, we sought to identify whether this immunophenotypic change occurs following other treatment types, including standard purine nucleoside analog therapy and with targeted BTK inhibition. Methods: Adult patients (≥18 years) with a diagnosis of HCL whom had immunophenotype data collected before and after treatment between 2010 and 2018 were included in the study. Immunophenotype and morphological characteristics of initial and follow-up peripheral blood, bone marrow aspirate, and core biopsy specimens were reviewed and correlated with the treatment received. Results: We evaluated 30 HCL patients who underwent different therapies. All available specimens were reviewed and showed morphologic features characteristic for cHCL (n=26, 86.7%), and aHCL (n=4, 13.3%). The median age at HCL diagnosis was 50 years (44-76 years) with male predominance (76%). Patients with aHCL were treated with ibrutinib (n=2) and pentostatin (n=2). Patients with cHCL were treated with pentostatin (n=12), ibrutinib (n=8), vemurafenib (n=4), dabrafenib (n=1), and cladribine (n=1). Bone marrow analyses showed that all the patients had leukemic B-lymphocyte co-expression of CD19, CD20, CD103, CD11c, CD25, and CD123 prior to treatment. Some patients also had a smaller percentage of lymphocytes lacking CD25 expression along with the CD25 positive lymphocytes. Follow-up bone marrow and peripheral blood analysis showed that almost half (n=14, 46%) of treated patients had a partial or complete loss of CD25 expression regardless of the treatment type. Leukemic cells continued to express other HCL signature markers. Conclusion: Our study indicates that during the course of disease some patients display a loss of CD25 expression after therapy. This phenomenon was observed across different therapies and is not specific to the type of treatment. This is the first study to show treatment-dependent CD25 variability with pentostatin, ibrutinib and dabrafenib. Our results advocate for caution when using CD25 for the differential diagnosis of cHCL versus HCLv in treated patients. Future studies are needed in larger patient cohorts to determine the overall role and utility of CD25 in the diagnosis of cHCL and HCLv. Disclosures Lozanski: Genentech: Research Funding; Stem Line: Research Funding; BI: Research Funding; Novartis: Research Funding; Beckman: Research Funding; Coulter: Research Funding. Andritsos:Astra Zeneca: Consultancy; HCLF: Membership on an entity's Board of Directors or advisory committees.

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Co-Treatment Of Hairy Cell Leukemia and Melanoma With The BRAF Inhibitor Dabrafenib

Blood ◽

10.1182/blood.v122.21.5311.5311 ◽

2013 ◽

Vol 122 (21) ◽

pp. 5311-5311 ◽

Cited By ~ 2

Author(s):

Leslie A. Andritsos ◽

James S. Blachly ◽

Kari Kendra ◽

Gerard Lozanski ◽

Michael R. Grever

Keyword(s):

Bone Marrow ◽

Malignant Melanoma ◽

Hairy Cell Leukemia ◽

Braf Mutation ◽

Braf Inhibitor ◽

Braf V600e Mutation ◽

Braf V600e ◽

Hairy Cell ◽

Cell Leukemia ◽

Marrow Cellularity

Abstract The activating BRAF mutation V600E has been identified in many human cancers, including colon and lung adenocarcinoma, papillary thyroid cancer, malignant melanoma, and hairy cell leukemia. Here we report for the first time treatment of hairy cell leukemia and malignant melanoma both harboring the BRAF V600E mutation with the BRAF inhibitor dabrafenib. The patient is a 67-year-old man with a history of classic hairy cell leukemia (immunophenotype CD11c, CD19, CD20 (bright), CD25, and CD103). At the time of diagnosis he had pancytopenia and received therapy with cladribine 0.12 mg/kg/day as a 2 hour infusion daily for 5 days, achieving a complete hematologic remission (CHR). His disease recurred 2 years later and he was again treated with cladribine 0.9 mg/kg/day as a 7 day continuous infusion, achieving a CHR. He remained in remission for 5 years, and this time received salvage therapy with pentostatin 4 mg/m2 every 2 weeks for a total of 12 doses. He achieved a CHR with minimal residual disease on bone marrow biopsy (0.3% of lymphocytes). He also had dyserythropoiesis concerning for myelodysplastic syndrome in addition to neurologic toxicity with gait imbalance. He was managed expectantly for the next 2 years, during which time he developed an 8 mm red nodule on the extensor surface of his right forearm, and a shave biopsy showed nodular melanoma, Clark’s level IV. He underwent a wide local excision with a negative axillary sentinel lymph node biopsy followed by adjuvant sargramostim (GM-CSF) for 12 months. His melanoma then recurred at the site of the prior excision. A PET scan showed an additional lesion in the midportion of the right arm. The excised solitary recurrence was sent for BRAF V600E mutation testing, which was positive. He received a course of radiotherapy (30 Gy over 14 days) to the affected limb, after which he had no evidence of disease. During this time, he was found to have worsening thrombocytopenia and splenomegaly, as well as a rising IL2 receptor level (peak 3952 U/mL; normal < 970), while bone marrow biopsy showed a 20% cellular marrow with 40% involvement by classic HCL. BRAF testing of the bone marrow by Sanger sequencing was positive for the V600E mutation. Because both his HCL and melanoma harbored the BRAF V600E mutation, the patient was eligible for and enrolled on a phase I clinical trial of dabrafenib for BRAF V600E mutant malignancies. Dabrafenib was initiated orally at a dose of 150 mg twice daily. Each cycle was 28 days. After 3 cycles, the bone marrow cellularity had improved to 30% with a decrease in the leukemic content to 10-15% of marrow cellularity. After 6 cycles, the bone marrow cellularity was normal for age with no residual HCL detectable by immunohistochemical stains or flow cytometric immunophenotyping. PET/CT scan at this time demonstrated no FDG avid lesions and no splenomegaly. Toxicites have consisted of characteristic RAF-associated skin changes and one instance of squamous cell carcinoma, which was excised. He has otherwise had no side effects from therapy. The patient has now completed 12 cycles of therapy with dabrafenib without evidence of either HCL or melanoma. He will remain on therapy as long as he is deriving clinical benefit per protocol. Given the increased risk of second primary malignancies in HCL, BRAF mutation testing should be considered for patients developing solid tumors in which this has been described, as co-treatment may be possible. Disclosures: Off Label Use: Dabrafenib for treatment of hairy cell leukemia. Kendra:Glaxo Smith-Kline: Research Funding.

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The effectiveness of rubidazone in hairy cell leukemia (leukemic reticuloendotheliosis)

Blood ◽

10.1182/blood.v54.2.298.298 ◽

1979 ◽

Vol 54 (2) ◽

pp. 298-304 ◽

Cited By ~ 35

Author(s):

DJ Stewart ◽

RS Benjamin ◽

KB McCredie ◽

S Murphy ◽

M Keating

Keyword(s):

Bone Marrow ◽

Hairy Cell Leukemia ◽

Leukemic Cells ◽

Alternative Methods ◽

Hairy Cell ◽

Cell Leukemia ◽

Anthracycline Antibiotic ◽

Initial Management ◽

Patients Âgés ◽

Life Threatening

Abstract Two patients with hairy cell leukemia treated with the anthracycline antibiotic rubidazone are presented. One achieved a complete remission and the other a good partial hematologic and bone marrow remission. Neither has relapsed (at 20 and 13 mo, respectively), and neither has been retreated. Intensive supportive measures were required during the prolonged myelosuppression that followed treatment. The relative youth of the patients (ages 24 and 39 yr) may have contributed to their ability to survive until normal marrow recovered. Chemotherapy should not be employed in the initial management of hairy cell leukemia. However, if life-threatening granulocytopenia and thrombocytopenia occur secondary to bone marrow replacement by leukemic cells, and improvement does not occur using alternative methods of therapy, consideration could be given to chemotherapy with rubidazone. Facilities for intensive supportive care should be available.

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