RARE DISEASE
T-cell prolymphocytic leukemia
T-cell prolymphocytic leukemia
T-cell prolymphocytic leukemia
Synonyms: T-PLL, T-cell chronic lymphocytic leukemia
Synonyms: T-PLL, T-cell chronic lymphocytic leukemia
Synonyms: T-PLL, T-cell chronic lymphocytic leukemia
Drug discovery
3
drugs
With orphan designations
Overview
T-cell prolymphocytic leukemia (T-PLL) is an aggressive mature T-cell malignancy characterized by rapid proliferation of post-thymic lymphocytes. It typically presents with hepatosplenomegaly, lymphadenopathy, marked leukocytosis (>100 × 10⁹/L), and cytopenias. Genetic drivers include TCL1 overexpression (80-90% of cases) and ATM mutations [1][4][10]. Median survival is 1–2 years despite alemtuzumab-based therapy, with relapse rates exceeding 80% [2][3][12].
Therapies
Categories: rare hematological diseases, rare neoplastic diseases, rare transplant-related disorders
Research Papers
282 drug discovery papers about T-cell prolymphocytic leukemia, with 2 first-in-class and 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
282 drug discovery papers about T-cell prolymphocytic leukemia, with 2 first-in-class and 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
2026-05-28 | Allogeneic stem cell transplantation in T-cell prolymphocytic leukemia: final disappointment or a chance for cure?
Not available.
2026-04-09 | A case of T-prolymphocytic leukemia harboring RAS mutation.
The text reports the clinical case of a 61-year-old woman with a long history of generalized pruritus who was eventually diagnosed with T-cell prolymphocytic leukemia (T-PLL), a rare and aggressive T-cell lymphoproliferative disorder. At presentation, the patient had fever, skin lesions, lymphocytosis, thrombocytopenia, coagulation abnormalities, and marked splenomegaly without lymphadenopathy. Morphological, immunophenotypic, and histological analyses of peripheral blood and bone marrow revealed diffuse infiltration by mature T lymphocytes with strong TCL1 expression, and T-cell receptor gene rearrangement confirmed clonality, supporting the diagnosis of T-PLL. The patient initially received bendamustine chemotherapy, which failed to induce a response. Second-line treatment with the anti-CD52 monoclonal antibody alemtuzumab was subsequently initiated, but the disease proved refractory, with persistent bone marrow involvement, worsening cytopenias, disease progression, and clinical deterioration. As a result, alemtuzumab was discontinued and the patient was transitioned to palliative care. A particularly notable finding was the detection, by next-generation sequencing, of a pathogenic KRAS G12A mutation, which has not previously been reported in T-PLL. This mutation was identified incidentally using a myeloid-targeted NGS panel. The finding broadens the known mutational spectrum of T-PLL and suggests that activation of the RAS signaling pathway may represent an alternative oncogenic mechanism beyond the canonical TCL1 and JAK–STAT pathways. We suggest that investigating for KRAS mutations in additional T-PLL cases may be beneficial to explore this pathogenetic pathway and could open new avenues for future targeted therapeutic strategies.
2026-03-30 | Allogeneic transplant outcomes in T-cell prolymphocytic leukemia: a single-center retrospective study.
T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive malignancy with a poor prognosis. Allogeneic hematopoietic stem cell transplantation (HCT) is often used for treatment, but its effectiveness remains unclear. In this study of 33 adult patients with T-PLL who underwent HCT, 5-year progression-free survival (PFS) was 29% (95% confidence interval [CI], 14-45) and 5-year overall survival (OS) was 41% (95% CI, 24-57). Five-year cumulative incidence of non-relapse mortality was 18%, while 5-year cumulative incidence of relapse was 53%. Univariable analysis revealed that a longer time from diagnosis to HCT was significantly associated with improved PFS (hazard ratio, 0.36; 95% CI, 0.15-0.87). Analysis of immune reconstitution in 22 patients showed a relatively slow recovery of immune cells post-HCT. A higher recovery of CD3 T cells was also associated with increased risk of relapse, which may have prognostic significance and warrants further investigation as a risk factor for disease recurrence.
2026-03-28 | How We Evaluate and Treat Leukemic Presentations of Mature T-Cell Lymphomas.
T-cell non-Hodgkin lymphomas, which arise from post-thymic mature T cells, constitute approximately 10-15% of all non-Hodgkin lymphomas. Their leukemic presentations, referred to here as mature T-cell leukemias, are relatively uncommon and present significant diagnostic and therapeutic challenges requiring an informed approach to diagnosis and management. The initial presentation is often persistent T-cell lymphocytosis that must be distinguished from reactive (non-malignant) causes. Unlike B-cell lymphocytosis, where clonality usually indicates malignancy, T-cell clonality can be detected in benign conditions such as autoimmune disorders and viral infections. Thus, establishing clonality is helpful but not sufficient, and a systematic diagnostic approach integrating clinical features, morphology, immunophenotype, and molecular findings is critical. This review outlines our approach to the diagnosis and treatment of four major subtypes of mature T-cell leukemias: T-cell prolymphocytic leukemia (T-PLL), adult T-cell leukemia/lymphoma (ATLL), T-large granular lymphocytic leukemia (T-LGL), and Sézary syndrome (SS). Each section includes a discussion of clinical features, workup, and treatment options.
2026-03-16 | UMG1 Defines a Targetable Subset of T-Cell Lymphomas and Enables Precision Immunotherapy With a First-in-Class CD3ε Bispecific Engager.
T-cell lymphomas (TCLs) account for a relatively small fraction of lymphoid malignancies and are characterized by highly aggressive course often refractory to current available therapies. We previously reported potent in vitro and in vivo antitumor activity of a Bispecific T-Cell Engager (UMG1/CD3ε-BTCE) directed against UMG1, a unique CD43 epitope that is abundantly expressed on T-cell acute lymphoblastic leukemia (T-ALL) and diffuse large B-cell lymphoma (DLBCL) cells, while absent in most normal tissues, except thymocytes and a small fraction of peripheral blood T lymphocytes (< 5%). Here, we investigated the in vitro efficacy of UMG1/CD3ε-BTCE against TCLs. IHC analysis of Tissue Micro Arrays (TMAs) revealed high UMG1 expression in 62.3% of TCL samples, including peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) and ALK-negative anaplastic large cell lymphoma (ALCL). Notably, all T-PLL primary specimens (27/27) were positive, and 3 of 4 TCL cell lines also expressed UMG1 by flow cytometry. The asymmetric UMG1/CD3ε-BTCE induced robust redirected cytotoxicity against UMG1-expressing TCL cells. Moreover, this activity was strengthened by cell exposure to the HDAC inhibitor SAHA. We observed a dose-dependent engaged T-cell-mediated cytotoxicity and inflammatory cytokine release, resulting in lysis of UMG1-expressing cells, with no significant effect on UMG1-not expressing cells. Our findings suggest that the UMG1/CD3ε-BTCE selectively exerts potent anti-tumor activity against a relevant subset of TCLs. These findings support the development of a precision immunotherapy approach for patients with UMG1-expressing aggressive hematologic malignancies.
2026-05-28 | Allogeneic stem cell transplantation in T-cell prolymphocytic leukemia: final disappointment or a chance for cure?
Not available.
2026-04-09 | A case of T-prolymphocytic leukemia harboring RAS mutation.
The text reports the clinical case of a 61-year-old woman with a long history of generalized pruritus who was eventually diagnosed with T-cell prolymphocytic leukemia (T-PLL), a rare and aggressive T-cell lymphoproliferative disorder. At presentation, the patient had fever, skin lesions, lymphocytosis, thrombocytopenia, coagulation abnormalities, and marked splenomegaly without lymphadenopathy. Morphological, immunophenotypic, and histological analyses of peripheral blood and bone marrow revealed diffuse infiltration by mature T lymphocytes with strong TCL1 expression, and T-cell receptor gene rearrangement confirmed clonality, supporting the diagnosis of T-PLL. The patient initially received bendamustine chemotherapy, which failed to induce a response. Second-line treatment with the anti-CD52 monoclonal antibody alemtuzumab was subsequently initiated, but the disease proved refractory, with persistent bone marrow involvement, worsening cytopenias, disease progression, and clinical deterioration. As a result, alemtuzumab was discontinued and the patient was transitioned to palliative care. A particularly notable finding was the detection, by next-generation sequencing, of a pathogenic KRAS G12A mutation, which has not previously been reported in T-PLL. This mutation was identified incidentally using a myeloid-targeted NGS panel. The finding broadens the known mutational spectrum of T-PLL and suggests that activation of the RAS signaling pathway may represent an alternative oncogenic mechanism beyond the canonical TCL1 and JAK–STAT pathways. We suggest that investigating for KRAS mutations in additional T-PLL cases may be beneficial to explore this pathogenetic pathway and could open new avenues for future targeted therapeutic strategies.
2026-03-30 | Allogeneic transplant outcomes in T-cell prolymphocytic leukemia: a single-center retrospective study.
T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive malignancy with a poor prognosis. Allogeneic hematopoietic stem cell transplantation (HCT) is often used for treatment, but its effectiveness remains unclear. In this study of 33 adult patients with T-PLL who underwent HCT, 5-year progression-free survival (PFS) was 29% (95% confidence interval [CI], 14-45) and 5-year overall survival (OS) was 41% (95% CI, 24-57). Five-year cumulative incidence of non-relapse mortality was 18%, while 5-year cumulative incidence of relapse was 53%. Univariable analysis revealed that a longer time from diagnosis to HCT was significantly associated with improved PFS (hazard ratio, 0.36; 95% CI, 0.15-0.87). Analysis of immune reconstitution in 22 patients showed a relatively slow recovery of immune cells post-HCT. A higher recovery of CD3 T cells was also associated with increased risk of relapse, which may have prognostic significance and warrants further investigation as a risk factor for disease recurrence.
2026-03-28 | How We Evaluate and Treat Leukemic Presentations of Mature T-Cell Lymphomas.
T-cell non-Hodgkin lymphomas, which arise from post-thymic mature T cells, constitute approximately 10-15% of all non-Hodgkin lymphomas. Their leukemic presentations, referred to here as mature T-cell leukemias, are relatively uncommon and present significant diagnostic and therapeutic challenges requiring an informed approach to diagnosis and management. The initial presentation is often persistent T-cell lymphocytosis that must be distinguished from reactive (non-malignant) causes. Unlike B-cell lymphocytosis, where clonality usually indicates malignancy, T-cell clonality can be detected in benign conditions such as autoimmune disorders and viral infections. Thus, establishing clonality is helpful but not sufficient, and a systematic diagnostic approach integrating clinical features, morphology, immunophenotype, and molecular findings is critical. This review outlines our approach to the diagnosis and treatment of four major subtypes of mature T-cell leukemias: T-cell prolymphocytic leukemia (T-PLL), adult T-cell leukemia/lymphoma (ATLL), T-large granular lymphocytic leukemia (T-LGL), and Sézary syndrome (SS). Each section includes a discussion of clinical features, workup, and treatment options.
2026-03-16 | UMG1 Defines a Targetable Subset of T-Cell Lymphomas and Enables Precision Immunotherapy With a First-in-Class CD3ε Bispecific Engager.
T-cell lymphomas (TCLs) account for a relatively small fraction of lymphoid malignancies and are characterized by highly aggressive course often refractory to current available therapies. We previously reported potent in vitro and in vivo antitumor activity of a Bispecific T-Cell Engager (UMG1/CD3ε-BTCE) directed against UMG1, a unique CD43 epitope that is abundantly expressed on T-cell acute lymphoblastic leukemia (T-ALL) and diffuse large B-cell lymphoma (DLBCL) cells, while absent in most normal tissues, except thymocytes and a small fraction of peripheral blood T lymphocytes (< 5%). Here, we investigated the in vitro efficacy of UMG1/CD3ε-BTCE against TCLs. IHC analysis of Tissue Micro Arrays (TMAs) revealed high UMG1 expression in 62.3% of TCL samples, including peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) and ALK-negative anaplastic large cell lymphoma (ALCL). Notably, all T-PLL primary specimens (27/27) were positive, and 3 of 4 TCL cell lines also expressed UMG1 by flow cytometry. The asymmetric UMG1/CD3ε-BTCE induced robust redirected cytotoxicity against UMG1-expressing TCL cells. Moreover, this activity was strengthened by cell exposure to the HDAC inhibitor SAHA. We observed a dose-dependent engaged T-cell-mediated cytotoxicity and inflammatory cytokine release, resulting in lysis of UMG1-expressing cells, with no significant effect on UMG1-not expressing cells. Our findings suggest that the UMG1/CD3ε-BTCE selectively exerts potent anti-tumor activity against a relevant subset of TCLs. These findings support the development of a precision immunotherapy approach for patients with UMG1-expressing aggressive hematologic malignancies.
Access all drug discovery papers and probability of success in trials forecasts:
Access all drug discovery papers and probability of success in trials forecasts:
Drug Discovery Landscape
3 orphan drug designations for T-cell prolymphocytic leukemia.
3 orphan drug designations for T-cell prolymphocytic leukemia.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
Tinostamustine | small molecules | EMA | 2020-07-27 | — | Mundipharma Corporation (Ireland) Limited |
tinostamustine hydrochloride | small molecules | FDA | 2019-03-15 | — | Knoa Pharma LLC |
(1S)-1-(9-deazahypoxanthin-9-yl)-1,4-dideoxy-1,4-imino-D-ribitol-hydrochloride | small molecules | FDA | 2004-08-10 | — | Mundipharma Research Ltd. |
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