Durability of complete remission by moxetumomab pasudotox (HA22 or CAT-8015) assessed by clone-specific real-time quantitative PCR (RQ-PCR).

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2503-2503
Author(s):  
Robert J. Kreitman ◽  
Evgeny Arons ◽  
Jeffrey Sapolsky ◽  
Laura Roth ◽  
Hong Zhou ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Real Time ◽  
Quantitative Pcr ◽  
Hairy Cell Leukemia ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Real Time Quantitative Pcr ◽  
Recombinant Immunotoxin

2503^ Background: The anti-CD22 recombinant immunotoxin moxetumomab pasudotox, also known as HA22 or CAT-8015, was recently reported in phase I testing to achieve complete remissions (CRs) in 13 (46%) of 28 patients with relapsed/refractory hairy cell leukemia (HCL); 3 of 13 patients have relapsed. Methods: To complete this trial, 20 additional patients received the highest dose level (50 µg/Kg every other day x 3 doses); none of the 48 HCL patients had dose-limiting toxicity (DLT). Results: Of the first 42 patients with >6 mo of follow up off-treatment, 23 (55%) had CRs, with an overall response rate of 88%. Of the 23 CRs, 21 were evaluable for minimal residual disease (MRD) using flow cytometry of blood and immunohistochemistry of the bone marrow biopsy, and 17 (81%) were negative. Of these 17 patients, 11 (65%) were negative by bone marrow aspirate (BMA) flow cytometry. PCR using consensus primers for the heavy chain immunoglobulin (IgH) rearrangement was less specific than flow cytometry of blood, since IgH rearrangements of normal B cells, which recovered rapidly after immunotoxin treatment, were also amplified. For better MRD detection in blood, patient IgH sequences were cloned and sequence specific primers and probes designed for real-time quantitative PCR (RQ-PCR). RQ-PCR of blood was negative in 6 (100%) of 6 patients achieving flow-negativity in both blood and BMA and positive in 3 (100%) of 3 patients flow-negative in blood but not BMA (p=0.01). No relapses from CR have been observed in 10 patients who became RQ-PCR-negative in blood or flow-negative in BMA, with 5-38 (median 11) mo of follow-up. Conclusions: We conclude that clone-specific RQ-PCR is the most sensitive blood test for MRD in our HCL patients after moxetumomab pasudotox, and could be used to assess the possibility of long-term molecular remissions. We believe these results, including durable CRs without DLT, support a pivotal trial in which moxetumomab pasudotox is compared with alternative therapy. Note: this summary contains investigator reported data. This study was funded by MedImmune, LLC, and supported by NCI’s Intramural Research Program and the Hairy Cell Leukemia Research Foundation.

Treatment of hairy cell leukemia with alternating cycles of pentostatin and recombinant leukocyte A interferon: results of a phase II study.

1990 ◽  
Vol 8 (4) ◽  
pp. 721-730 ◽  
Author(s):  
A Martin ◽  
S Nerenstone ◽  
W J Urba ◽  
D L Longo ◽  
J B Lawrence ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Hairy Cell Leukemia ◽  
Pathologic Complete Response ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Cell Infiltrate ◽  
Recombinant Interferon ◽  
Bone Marrow Biopsies ◽  
Hairy Cells

Fifteen patients with hairy cell leukemia (HCL) were treated with deoxycoformycin (pentostatin; dCF) (4 mg/m2 intravenous [IV] every week x 3) and recombinant interferon-alpha 2a (rIFN-alpha 2a) (3 x 10(6) units subcutaneously [SC] daily x 4 weeks) in alternating months for a total of 14 months. Eleven patients had undergone splenectomy; four had received prior systemic therapy with chlorambucil and/or steroids. All 15 are evaluable for toxicity and peripheral blood response, while 14 are assessable for bone marrow response. Toxicity was tolerable with grade 3 or 4 nausea and vomiting in three patients, neutropenic fevers in five, transient but significant depression in eight, and localized cutaneous herpes zoster in four. Circulating hairy cells were undetectable by the end of the first month in 10 of 13 patients, and by the end of the second month in the other three. Fourteen patients had bilateral bone marrow biopsies performed at baseline after 6 months of treatment, at the end of treatment (14 months), and at 6-month intervals during follow-up. Before treatment, all patients had hypercellular marrows with hairy cels replacing normal marrow elements; all showed at least a 95% clearing of their hairy cell infiltrate by 6 months of therapy. However, small collections of residual hairy cells could be detected intermittently on at least one side of bilateral samples in all patients. All patients have completed treatment with a median duration of follow-up off therapy of 27 months (range, 15 to 31 months). To date, all peripheral counts and serum soluble interleukin-2 receptor (sIL2R) levels remain stable, and no patient has had progression of the hairy cell infiltrate in the bone marrow. Although no patient achieved a pathologic complete response, alternating monthly cycles of dCF and rIFN-alpha 2a produced durable partial remissions (PRs) in all patients. Continued follow-up is required to determine the length of such remissions.

scholarly journals Minimal residual disease may predict bone marrow relapse in patients with hairy cell leukemia treated with 2-chlorodeoxyadenosine

Blood ◽  
1996 ◽  
Vol 87 (4) ◽  
pp. 1556-1560 ◽  
Author(s):  
S Wheaton ◽  
MS Tallman ◽  
D Hakimian ◽  
L Peterson
Keyword(s):  
Bone Marrow ◽  
Minimal Residual Disease ◽  
Hairy Cell Leukemia ◽  
Residual Disease ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Hematoxylin And Eosin ◽  
Anti Cd20 ◽  
Minimal Residual

Minimal residual disease (MRD) can be detected in bone marrow core biopsies of patients with hairy cell leukemia (HCL) after treatment with 2-chlorodeoxyadenosine (2-CdA) using immunohistochemical (IHC) techniques. The purpose of this study was to determine whether the presence of MRD predicts bone marrow relapse. We studied paraffin- embedded bone marrow core biopsies from 39 patients with HCL in complete remission (CR) 3 months after a single cycle of 2-CdA. Biopsies performed 3 months posttherapy and annually thereafter were examined by routine hematoxylin and eosin (H&E) staining and IHC using the monoclonal antibodies (MoAbs) anti-CD45RO, anti-CD20, and DBA.44. At 3 months after therapy, 5 of 39 (13%) patients had MRD detectable by IHC that was not evident by routine H&E staining. Two of the five patients (40%) with MRD at 3 months have relapsed, whereas only 2 of 27 (7%) patients with no MRD and at least 1 year of follow up relapsed (P = .11). Over the 3-year follow-up period, two additional patients developed MRD. Overall, three of six (50%) patients with MRD detected at any time after therapy have relapsed, whereas only 1 of 25 (4%) patients without MRD has relapsed (P = .016). These data suggest that the presence of MRD after treatment with 2-CdA may predict relapse.

scholarly journals Usefulness of Dual Immunohistochemistry Staining in Detection of Hairy Cell Leukemia in Bone Marrow

2019 ◽  
Vol 153 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Gaurav K Gupta ◽  
Xiaoping Sun ◽  
Constance M Yuan ◽  
Maryalice Stetler-Stevenson ◽  
Robert J Kreitman ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Hairy Cell Leukemia ◽  
Predictive Value ◽  
Lymphoid Cells ◽  
Multiparameter Flow Cytometry ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Flow Cytometry Data ◽  
Flow Cytometric Data

Abstract Objectives We evaluated efficacy of two dual immunohistochemistry (IHC) staining assays in assessing hairy cell leukemia (HCL) involvement in core biopsies and compared the results with concurrently collected flow cytometric data. Methods Overall, 148 patients with HCL (123 male, 25 female; mean age: 59.8 years; range: 25-81 years) had multiparameter flow cytometry performed using CD19, CD20, CD22, CD11c, CD25, CD103, CD123, surface light chains, CD5, and CD23. In parallel, bone marrow IHC was done using PAX5/CD103 and PAX5/tartrate-resistant alkaline phosphatase (TRAP) dual IHC stains. Results Overall sensitivity of dual IHC stains was 81.4%, positive predictive value was 100%, and negative predictive value was 81.7%. All IHC-positive cases concurred with flow cytometry data, even when HCL burden was extremely low in the flow cytometry specimens (as low as 0.02% of all lymphoid cells). Conclusions Dual IHC stain is a sensitive tool in detecting HCL, even in cases with minimal disease involvement.

scholarly journals The Role of Novel Dual Color Immunohistochemistry in Detection of Minimal Hairy Cell Leukemia in Bone Marrow: A Study of 148 Cases

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4859-4859
Author(s):  
Gaurav K. Gupta ◽  
Xiaoping Sun ◽  
Constance M. Yuan ◽  
Maryalice Stetler-Stevenson ◽  
Robert J. Kreitman ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Hairy Cell Leukemia ◽  
Predictive Value ◽  
Lymphoid Cells ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Flow Cytometry Data ◽  
Flow Cytometric ◽  
Minimal Disease

Abstract Background: Hairy-cell leukemia (HCL) is a B-cell lymphoproliferative disorder characterized by distinct immunophenotype (positive for CD19, CD20, PAX5, CD22, CD11c, CD25, CD103, CD123 and CD200). Both flow cytometry (FC) and immunohistochemistry (IHC) can be used to determine these markers, while the expression of another marker (TRAP) is IHC specific. Both trephine bone marrow biopsy and aspirate are vital for assessment of extent of bone marrow infiltration. However, in some cases a cellular aspirate cannot be obtained due to extensive fibrosis, ie "dry tap". In such cases, IHC stains are crucial for assessment of bone marrow leukemic involvement. So far, IHC detection of HCL in the bone marrow sections has been limited to overt disease and could not be reliably used in cases with minimal HCL involvement. Novel automated dual-antibody immunohistochemistry techniques can identify aberrant antigen co-expression in neoplastic cells with high sensitivity. Consistent detection of minimal disease involvement is crucial given that treatment decisions are sometimes based on these data (Grever et. al. Blood 2017). In this study, we evaluated the efficacy of two novel dual IHC assays in assessing minimal HCL involvement in the core biopsies and compared the results with concurrently collected flow cytometric data. Design: We analyzed data on 148 cases of HCL (123 male, 25 female; mean age 59.8, range 25-81). All cases had multiparameter flow cytometry performed using CD19, CD20, CD22, CD11c, CD25, CD103, CD123, surface light chains, CD5 and CD23. In parallel, bone marrow IHC was done using PAX5/CD103 and PAX5/TRAP dual stains and the automated stainer (Ventana Ultra). Results: Cases were divided into three groups based on the combined results of PAX5/CD103 and PAX5/TRAP stains: negative (82; 55.4%); rare dual positive cells (less than 5% of total cells) (21; 14.1%) and positive (45; 30.4%). Flow cytometry data concurred with IHC results in all IHC positive cases (median 7.05% HCL cells out of all lymphoid cells by FC; range 0.05%-91.7%) and all rare dual-cell IHC positive cases (median 0.98% HCL cells; range 0.02%-19.04%). Overall sensitivity of dual IHC was 81.4%, positive predictive value 100% and negative predictive value 81.7%. In dual IHC negative group, 15/82 cases (18.3%) were low level positive by FC analysis (median 0.13% HCL cells; range 0.01%-9.21%). When dual IHC results were analyzed separately, PAX5/CD103 results were similar to the combined results. PAX5/TRAP staining alone was slightly less sensitive in IHC negative cases; 22/82 (26.8%) of PAX5/TRAP negative or non-evaluable cases were positive by FC analysis (median 0.27% HCL cells, range 0.01%-29.5%). Conclusion: Dual color IHC is a sensitive tool in detecting HCL, even in cases with minimal disease involvement. All IHC positive cases concurred with flow cytometry data, even when HCL burden was extremely low (as low as 0.02% of all lymphoid cells by flow cytometric analysis). Only 18.3% of dual IHC negative cases were positive for low level involvement by FC analysis. Therefore, dual IHC is a sensitive new tool for evaluation of minimal marrow involvement by HCL. Figure. Figure. Disclosures Kreitman: NIH: Patents & Royalties: Co-inventor on the NIH patent for Moxetumomab Pasudotox.

scholarly journals Flow cytometry of blood and bone marrow cells from patients with hairy cell leukemia: phenotype of hairy cells and lymphocyte subsets after treatment with 2-chlorodeoxyadenosine

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3672-3681 ◽  
Author(s):  
G Juliusson ◽  
R Lenkei ◽  
J Liliemark
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Nk Cells ◽  
Hairy Cell Leukemia ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Cd4 Cells ◽  
Normal Range ◽  
Hla Dr ◽  
Hairy Cells

Abstract By flow cytometry and an extensive set of markers, we characterized leukemic cells from the blood and bone marrow of 68 symptomatic patients with hairy cell leukemia (HCL). Hairy cells identified in the large cell gate always expressed CD19, CD20, HLA-DR, CD45RA, and B-ly 7. Other markers were occasionally expressed, such as CD38, CD45RO, CD23, CD15, CD4, CD5, and CD10 (expressed on more than 20% of the hairy cells in 44%, 25%, 21%, 18%, 12%, 10%, and 5% of evaluated cases, respectively). During treatment with 2-chlorodeoxyadenosine (CdA), the median lymphocyte counts decreased from 2,000/microL to 300/microL. Flow cytometry was repeated at the nadir (n = 24) of lymphocyte counts, at 3 months (n = 46), at 6 months (n = 50), at 1 year (n = 39), and at 2 years (n = 12) after treatment. The initial decrease of CD8+ and CD20+ cells was greater than that of CD4+ and natural killer (NK) cells, leading to an increasing CD4/CD8 ratio. Median nadir values of CD4+, CD8+, CD20+, and NK cells were 128/microL, 78/microL, 10/microL, and 13/microL, respectively. The subsequent recovery was quicker for CD8+ and NK cells, leading to a normalization within 3 months, whereas CD20+ and CD4+ cells required 1 or 2 years to enter the normal range. The CD4/CD8 ratio thus decreased after the nadir and remained less than 1. CD45RA+ CD4 cells and CD45RA+/CD45RO+ double-positive cells were less affected by CdA. Activated T cells, ie, HLA-DR+ cells, rarely decreased below the normal range and often recovered with an overshoot. CD10+ cells increased in the bone marrow posttreatment as an indication of normal B-cell regeneration in 16 of 36 (44%) patients. The quick regeneration of certain lymphoid subsets might explain the lack of late infections in CdA-treated HCL patients.

Antigenic Variation of Hairy Cell Leukemia Defines a CD25 Negative Variant with a Uniform Immunophenotype and Distinct Clinicopathologic Features.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1102-1102
Author(s):  
Henry Y. Dong
Keyword(s):  
Flow Cytometry ◽  
Hairy Cell Leukemia ◽  
Standard Therapy ◽  
Overall Response Rate ◽  
Response Rate ◽  
Complete Response ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Overall Response

Abstract Classical hairy cell leukemia (HCL) coexpressing both CD25 and CD103 is highly responsive to the treatment with cladribine and pentostatin (complete response rate, 75–95%; overall response rate, 86–100%). HCL variant in the literature is characterized by HCL-like morphology, lack of CD25 coexpression, and variable immunophenotypes indistinguishable from those of splenic marginal zone B cell lymphoma (Matutes, et al. Leukemia2001; 15:184). Importantly, HCL variant is associated with a poor response to standard therapy. It is unclear if HCL cases lacking CD25 but otherwise phenotypically identical to classical HCL belong to HCL or HCL variant, and if the standard therapy is effective in these patients. To further delineate features of HCL and its variants, we analyzed immunophenotyping data, by flow cytometry or immunohistochemistry, or by both when feasible, in 260 consecutive patients with HCL (Dong, et al. Mod Pathol2003; 16:230A). The diagnosis was established by hairy cell morphology together with coexpression of strong CD20 and CD22, bright CD11c, and CD103. Clinical data were obtained for a subset of cases in which expression of CD25 was distinctly absent. Our results were consistent with the literature in that HCL has a consistent and unique immunophenotypic profile, which allowed detection of residual HCL by flow cytometry at levels as low as 0.1% of total cells. In addition, approximately 20% and 37% of classical HCL coexpressed CD10 and BCL-1 respectively, which may significantly confuse the diagnosis in an incomplete work-up. Interestingly, there were 43 cases (20% of all CD103+ cases) that lacked CD25 but were otherwise identical to classical HCL in their uniform phenotypic profiles. Compared with classical HCL, patients with the CD25- HCL were generally older (medium age: 59yrs vs. 79yrs; p=0.001) and frequently had leukocytosis (medium WBC: 3.0x109/L vs. 24.5x109/L; p=0.014). Among 14 patients with follow up data, 7 were treated with cladribine or pentostatin. The complete response (CR) rate was 14.3% (1/7) and the overall response rate was 57.1% (4/7). Three patients had no response. One patient who had an initial partial response (PR) to pentostatin died of the disease 10 months after the diagnosis. Of others, an additional two patients achieved CR and PR upon initial treatment with fludarabine and Rituxamab respectively. Four patients were untreated and were alive with disease (follow up, 21–41 months). One patient died of the disease in 2 years and treatment for this patient was unknown. These clinical features overlapped with those of HCL variant in the literature. However, unlike the HCL variant that has significant phenotypic heterogeneity, including lack of CD11c and CD103 in a substantial number of cases, the CD25- HCL was remarkably uniform in phenotype and can be easily identified by immunophenotyping. In conclusion, these results suggest that lack of CD25 in HCL defines a clinically distinct chronic lymphoproliferative disorder, which appears to require different clinical management.

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 ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2896-2896 ◽  
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.

scholarly journals 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 ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 150-150 ◽  
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..

scholarly journals Immunomorphologic analysis of bone marrow biopsies after treatment with 2-chlorodeoxyadenosine for hairy cell leukemia

Blood ◽  
1994 ◽  
Vol 84 (12) ◽  
pp. 4310-4315 ◽  
Author(s):  
DJ Ellison ◽  
RW Sharpe ◽  
BA Robbins ◽  
JC Spinosa ◽  
JD Leopard ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Complete Remission ◽  
Hairy Cell Leukemia ◽  
Residual Disease ◽  
Positive Staining ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Bone Marrow Biopsies ◽  
Hairy Cells

Treatment of hairy cell leukemia with 2-chlorodeoxyadenosine (2-CdA) induces complete remissions in 85% of patients. Complete remission has been defined as the absence of hairy cells in the bone marrow after routine morphologic examination. To determine if hairy cells could be detected in complete remission bone marrows using immunohistochemical techniques with antibodies L26 (CD20) and DBA.44, 154 bone marrow biopsies performed between 3 months and 25 months after therapy were studied. Of the biopsies, 50% exhibited staining with L26 and/or DBA.44 in five or more cells with morphologic features of hairy cells. Minimal residual disease was usually less than 1% of the total cellular population. DBA.44-positive cells were demonstrated in 91% of the biopsies, although in 48% of these the morphologic features of the positive cells were not sufficiently distinctive for hairy cells. The proportion of biopsies with residual hairy cells was similar over the 25 months of follow up, indicating a relatively stable amount of residual disease. Immunomorphologic analysis is a more sensitive method for detecting residual hairy cells than morphology alone. Although further follow up is necessary to determine the clinical significance of the L26/DBA.44-positive staining in cells with and without distinctive morphologic features of hairy cells, we conclude that many patients in a stable clinical remission may have residual hairy cells.

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