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The best upfront therapy for patients with non-gastric extranodal marginal zone lymphomas (MZLs) is not defined. We assessed the safety and efficacy of radioimmunotherapy with (90)yttrium ((90)Y) ibritumomab tiuxetan as upfront therapy in MZL (NCT00453102). A total of 16 patients were enrolled, 81% with advanced-stage disease and 44% with bulky disease. The overall response rate (ORR) at 12 weeks post-therapy was 87.5% (90% confidence interval [CI]: 65.6-97.7%), including a complete response in eight (50%), complete response unconfirmed in one (6%) and partial response in five (31%) patients. With a median follow-up of 65.6 months (range 4.0-96.5), the median progression-free survival (PFS) was 47.6 months (range 4.0-93.3) and median overall survival (OS) was not reached. The 5-year PFS was 40% (90% CI: 19.9-59.5%) and 5-year OS was 71.8% (90% CI: 46.8-86.5%). Overall, (90)Y ibritumomab tiuxetan was well tolerated and led to long-term responses and PFS rates.

CD30 is abundantly and selectively expressed on the surface of Hodgkin Reed-Sternberg cells, anaplastic large cell lymphomas (ALCLs), and other lymphoid malignancies as well as on several non-lymphoid malignancies including selected germ cell tumors. Expression of CD30 on normal cells is highly restricted, thereby allowing differential targeting of malignant cells. CD30, a member of the tumor necrosis factor (TNF)-receptor family has pleiotropic biologic functions, and antibodies targeting CD30 and other TNF family receptors can exhibit both agonistic and antagonistic signaling functions. Recently, antibody-drug conjugates targeting CD30, such as brentuximab vedotin, have shown striking activity in phase I and II trials, with manageable toxicity. This has defined an important emerging role for targeting of CD30 in the setting of Hodgkin lymphoma, ALCL, and possibly other CD30+ malignancies.

Novel therapeutic approaches are needed in mantle cell lymphoma (MCL). We conducted a phase II study in MCL testing an intensive regimen, R-MACLO-IVAM-T, a modification of the NCI 89-C-41 protocol. Newly diagnosed patients were treated with rituximab, methotrexate, doxorubicin, cyclophosphamide, and vincristine (cycle 1) followed by rituximab, ifosfamide (and mesna), etoposide, and cytarabine (cycle 2). These two cycles were repeated once, and patients achieving complete response (CR) received maintenance thalidomide. Among the 22 patients enrolled, 21 completed two or more cycles and achieved a CR. Three patients relapsed, while 17 are alive and relapse-free after a median follow-up of 37 months (range 19-65 months). Two patients died: one from sepsis during cycle 1 and another at 38 months while in remission from MCL. The progression-free survival at 3 years was 78% (95% CI: 51-91%). These results compare favorably with previously reported outcomes suggesting that durable remissions can be achieved without myeloablative therapy.

Adult T-cell leukemia (ATL) associated with HTLV-1 infection is characterized by the development of hypercalcemia in over two thirds of patients. Dysregulation of cellular gene transcription by viral proteins is an emerging paradigm for molecular pathogenesis of disease. A recent example is the parathyroid hormone-related protein (PTHrP) gene, which has been implicated in the hypercalcemia of ATL, and is transactivated by the HTLV-1 tax and HTLV-11 tax proteins. PTHrP is expressed at high levels in leukemia cells derived from ATL patients, as well as in asymptomatic HTLV-1 positive carriers. This article reviews the interaction of the HTLV-1 transcriptional regulator tax with the PTHrP promoter. Tax mediates its effects on PTHrP via cellular transcription factors AP-2 and AP-1, and transactivation via an AP-2 motif represents a novel interaction of tax with a cellular transcription factor.