Ixabepilone and Carboplatin for Hormone Receptor Positive/HER2-neu Negative and Triple Negative Metastatic Breast Cancer.

BACKGROUND: Hormonal therapies and single-agent sequential chemotherapeutic regimens are the standards of care for HER2- metastatic breast cancer (MBC). However, treating patients with hormone-refractory and triple negative (TN) MBC remains challenging. We report the results of combined ixabepilone and carboplatin in a single-arm phase II trial. PATIENTS AND METHODS: In the present prospective analysis of hormone receptor-positive (HR+)/HER2- and TN MBC cohorts, patients could have received 0 to 2 chemotherapy regimens for MBC before enrollment. All patients received ixabepilone 20 mg/m2 and carboplatin (area under the curve, 2.5) on days 1 and 8 every 21 days. The primary endpoint was the objective response rate (ORR). The secondary objectives included progression-free survival (PFS), clinical benefit rate (CBR), overall survival (OS), and toxicity. RESULTS: We enrolled 54 HR+ and 49 TN patients (median, 1 previous chemotherapy regimen for metastatic disease; most in addition to adjuvant chemotherapy). The ORR was 34% and 30.4% for the HR+ and TN patients, respectively, with a corresponding CBR of 56.6% and 41.3%. The ORRs were similar in taxane-pretreated patients (ORR, 31.4% and 28.6% for HR+ and TN patients, respectively). The median OS was 17.9 months for HR+ patients and 12.5 months for TN patients. The median PFS was similar for both groups at 7.6 months. Grade 3/4 nonhematologic toxicities included neuropathy (9%) and fatigue (8%). Nine patients developed grade 3/4 neuropathy, 7 of whom had received previous taxane treatment. CONCLUSION: Ixabepilone plus carboplatin is active even in later-line HR+ and TN disease. Toxicities were manageable without cumulative myelosuppression. This combination is a reasonable option for those patients with MBC who require combination chemotherapy.

A phase 2 study of rituximab in combination with recombinant interleukin-2 for rituximab-refractory indolent non-Hodgkin's lymphoma.

PURPOSE: The incidence of non-Hodgkin's lymphoma (NHL), the fifth most common malignancy in the United States, has increased over 70% in the last 30 years. Fifty percent to 75% of patients with low-grade or follicular NHL respond to rituximab therapy. However, responses are generally of limited duration, and complete responses are rare. Preclinical work suggests that human recombinant interleukin-2 (rIL-2; aldesleukin, Proleukin) enhances rituximab efficacy. Antibody-dependent cellular cytotoxicity (ADCC) is an important mechanism of action of rituximab. rIL-2 induces expansion and activation of Fc receptor (FcR)-bearing cells, thereby enhancing ADCC. Therefore, a large, multicenter phase 2 trial to assess the effects of rIL-2 on rituximab therapy in patients with rituxumab-refractory low-grade NHL was conducted. EXPERIMENTAL DESIGN: The combination of rituximab and rIL-2 was studied in 57 patients with rituximab-refractory low-grade NHL (i.e., patients must have received a single-agent course of rituximab and showed no tumor response, or had a response lasting <6 months). I.V. rituximab was given at 375 mg/m(2) (weeks 1-4). S.C. rIL-2 was given thrice a week at 14 MIU (weeks 2-5) and at 10 MIU (weeks 6-9). RESULTS: Rituximab plus rIL-2 combination therapy was safe and generally well tolerated, but responses were low. Fifty-seven patients were enrolled with 54 evaluable for response; however, only five responses (one complete and four partial) were observed. Correlative data indicate that rIL-2 expanded FcR-bearing cells and enhanced ADCC. However, other factors, such as FcgammaR polymorphisms in patients refractory to single-agent rituxumab and heterogeneous tumor biology, may have influenced the lack of clinical efficacy seen with this combination therapy. CONCLUSIONS: rIL-2 expands FcR-bearing cellular subsets in vivo and enhances in vitro ADCC of rituxumab. However, these findings do not directly translate into meaningful clinical benefit for patients with rituxumab-refractory NHL.

Phase I study of the sequential combination of interleukin-12 and interferon alfa-2b in advanced cancer: evidence for modulation of interferon signaling pathways by interleukin-12.

PURPOSE: To evaluate the safety of sequentially administered recombinant (r) human (h) interleukin-12 (IL-12) and interferon alfa-2b (IFN-alpha-2b) in patients with advanced cancer and to determine the effects of endogenously produced IFN-gamma on Janus kinase-signal transducer and activator of transcription (Jak-STAT) signal transduction in patient peripheral-blood mononuclear cells (PBMCs). PATIENTS AND METHODS: Forty-nine patients with metastatic cancer received rhIL-12 on day 1 and IFN-alpha-2b on days 2 to 6 of either a 14-day (n = 43) or a 7-day treatment cycle (n = 6). rhIL-12 was initially administered subcutaneously at a dose of 100 ng/kg, whereas IFN-alpha-2b was escalated from 1 to 10 million units (MU) in cohorts of three patients (1, 3, 5, 7, or 10 MU). rhIL-12 was subsequently administered intravenously (IV) in escalating doses (100 to 500 ng/kg) to achieve greater IFN-gamma production. Peripheral blood was drawn for measurement of plasma IFN-gamma and the induction of Jak-STAT signal transduction in PBMCs. RESULTS: No IL-12-or IFN-alpha-related dose-limiting toxicities were observed. There were no responses in 41 assessable patients. Five patients exhibited stable disease lasting 6 months or longer while on therapy. Optimal induction of IFN-gamma by IL-12 occurred after an IV dose of 250 ng/kg. Patient PBMCs exhibited increased levels of STAT1 after IL-12 administration. The peak level of IFN-gamma achieved with IL-12 therapy correlated with the peak level of intracellular STAT1 in patient PBMCs (r = 0.38, P = .021). CONCLUSION: The combination of rhIL-12 and IFN-alpha-2b can be administered sequentially with minimal toxicity. IV administration of rhIL-12 modulates IFN-alpha-induced Jak-STAT signal transduction in patient PBMCs.

Durable hematologic complete response and suppression of HTLV-1 viral load following alemtuzumab in zidovudine/IFN-{alpha}-refractory adult T-cell leukemia.

Adult T-cell leukemia (ATL) is a highly chemoresistant and usually fatal T-cell malignancy due to the human T-cell lymphotropic virus-1 (HTLV-1). After chemotherapy failure, antiretrovirals and interferon-alpha (IFN-alpha) produce brief responses followed by progression and death. More effective agents and new approaches to detect and treat minimal residual disease are needed. ATL cells express CD52, the target of the antibody alemtuzumab, which is active in a preclinical model of ATL and is cytotoxic for p53-deficient cells. A patient with refractory chronic ATL in transformation achieved longer than a 1-year complete hematologic response following 12 weeks of outpatient subcutaneous alemtuzumab. Persistent suppression of HTLV-1 viral load, even at recovery of T cells, after alemtuzumab and efficient in vitro complement-mediated cytotoxicity of primary ATL cells with mutated TP53 were observed. The unprecedented response and the profound suppression of HTLV-1 viral load observed in this patient suggest that further clinical investigation of alemtuzumab in ATL is warranted.

IFN-gamma gene polymorphisms associate with development of EBV+ lymphoproliferative disease in hu PBL-SCID mice.

Posttransplantation lymphoproliferative disorder (PTLD) is a devastating post-transplantation complication often associated with Epstein-Barr virus (EBV). Although the type and length of immunosuppression are risk factors, a patient's inherent immune capacity also likely contributes to this disorder. This report uses severe-combined immunodeficient mice given injections of human peripheral blood leukocytes (hu PBL-SCID [Severe Combined Immunodeficient] mice) to test the hypothesis that cytokine genotype associates with the development of EBV-associated lymphoproliferative disease (LPD). We observed that the A/A (adenosine/adenosine) genotype for base + 874 of the interferon gamma (IFN-gamma) gene was significantly more prevalent in PBLs producing rapid, high-penetrance LPD in hu PBL-SCID mice, compared to PBLs producing late, low-penetrance LPD or no LPD. In examining the relationship between genotype and cytolytic T-lymphocyte (CTL) function, transforming growth factor beta (TGF-beta) inhibited restimulation of CTLs in PBLs with adenosine at IFNG base + 874, but not in PBLs homozygous for thymidine. Importantly, neutralization of TGF-beta in hu PBL-SCID mice injected with A/A genotype PBLs resulted in reduced LPD development and expanded human CD8(+) cells. Thus, our data show that TGF-beta may promote tumor development by inhibiting CTL restimulation and expansion. Further, our data indicate that IFNG genotype may provide valuable information for both identifying transplant recipients at greater risk for PTLD and developing preventive and curative strategies.

Selective efficacy of depsipeptide in a xenograft model of Epstein-Barr virus-positive lymphoproliferative disorder.

BACKGROUND: Immune-compromised individuals are at increased risk for developing aggressive Epstein-Barr virus (EBV)-associated lymphoproliferative disorders after primary EBV infection or for reactivation of a preexisting latent EBV infection. We evaluated the effect of depsipeptide, a histone deacetylase inhibitor, on EBV-positive lymphoblastoid cell lines (LCLs) and Burkitt lymphoma cell lines in a mouse model and explored its mechanism of action in vitro. METHODS: We studied EBV-transformed LCLs, which express a latent III (Lat-III) viral gene profile, as do some EBV-positive lymphoproliferative malignancies, and Burkitt lymphoma cell lines, which express a Lat-I viral gene profile. Cell lines were used to characterize depsipeptide-induced apoptosis, which was evaluated by flow cytometry. Flow cytometry, western blot analyses, and histone deacetylase inhibitors were used to investigate components of prodeath and survival pathways in vitro. We studied depsipeptide's effects on survival with a mouse xenograft model of EBV-positive human B-cell tumors (groups of 10 mice). All statistical tests were two-sided. RESULTS: Depsipeptide (5 mg/m2 of body surface area) treatment was associated with statistically significantly improved survival of mice carrying Lat-III EBV-positive LCL tumors, compared with that of control-treated mice (day 30: for depsipeptide-treated mice, 90% survival, 95% confidence interval [CI] = 73.2% to 100%; for control-treated mice, 20% survival, 95% CI = 5.79% to 69.1%; P<.001), but it was not associated with survival of mice carrying Lat-I EBV-positive Burkitt lymphoma tumors. Depsipeptide induced apoptosis in 64% of LCLs and in 14% of EBV-positive Burkitt lymphoma cells in vitro. Depsipeptide-treated LCL cultures had two distinct cell populations--one sensitive and one resistant to depsipeptide. Depsipeptide-mediated apoptosis was associated with a 12-fold increased level of active caspase 3, but some apoptosis persisted despite z-VAD-fmk treatment to inhibit caspase activity. Depsipeptide-resistant LCLs expressed higher levels of latent membrane protein 1 (LMP1; P = .017), BCL2 (P = .032), and nuclear factor kappaB (NF-kappaB) (P<.001) than depsipeptide-sensitive LCLs; this resistance was circumvented by treatment with PS-1145, an inhibitor of NF-kappaB activation (P<.001). CONCLUSIONS: Apoptosis is induced by depsipeptide via caspase-dependent and -independent pathways in Lat-III EBV-positive LCLs and is enhanced by inhibiting NF-kappaB activity. Depsipeptide as a treatment for Lat-III EBV-associated lymphoproliferative disorders should be explored further in clinical trials.

Combination immunotherapy of B-cell non-Hodgkin's lymphoma with rituximab and interleukin-2: a preclinical and phase I study.

PURPOSE: Cytokine-induced modulation of innate immunity is being explored to enhance the activity of monoclonal antibodies. Severe combined immunodeficient (SCID) mice engrafted with peripheral blood leukocytes (PBLs) from Epstein Barr virus-seropositive donors develop human B-cell non-Hodgkin's lymphomas [B-NHLs (hu-PBL-SCID mouse model)]. We used this hu-PBL-SCID mouse model to study the synergism between interleukin (IL)-2 and rituximab. We also conducted a phase I trial of IL-2 and rituximab in relapsed B-NHL to study whether expansion of natural killer (NK) cells and enhanced cellular cytotoxicity could be safely accomplished in vivo. EXPERIMENTAL DESIGN: Hu-PBL-SCID mice were treated with various schedules of rituximab and IL-2, with survival as the end point. Patients with relapsed B-NHL received rituximab (375 mg/m2 weekly x 4) followed by daily low-dose IL-2 (1 MIU/m2/day x 4 weeks) with pulses of intermediate-dose IL-2 (3-15 MIU/m2). Toxicity, NK cell numbers, and cellular cytotoxicity were measured. RESULTS: In the hu-PBL-SCID mouse, the combination of rituximab and IL-2 showed greater activity against B-NHL than either agent alone. Treatment was most effective when IL-2 was given before rituximab. Twelve patients with heavily pretreated B-NHL entered the phase I trial. Toxicity was manageable, and responses were observed. NK cell expansion and enhanced cellular cytotoxicity against a B-cell lymphoma target were observed but did not correlate with response. CONCLUSIONS: The combination of IL-2 and rituximab is synergistic against B-NHL in the hu-PBL-SCID model. In the phase I trial, a sequential combination of rituximab and IL-2 was well tolerated and achieved biological end points. Responses were observed.

Experimental treatment of Epstein-Barr virus-associated primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) that arises in immune-deficient patients is an aggressive B-cell neoplasm that is universally associated with the EBV. Patients with EBV(+) PCNSL face a particularly poor prognosis with median survival times of 2-12 months despite aggressive management with radiation therapy. We have developed a preclinical model of EBV(+) PCNSL to explore strategies that specifically target EBV-infected B lymphoblasts in vivo. Stereotactic implantation of EBV-transformed human lymphoblastoid B-cell lines into the caudate nucleus of the nude rat resulted in lethal CNS tumor burden manifested by the onset of focal neurological symptoms within 21 days. Histological evaluation at autopsy revealed a multifocal, perivascular human EBV(+) lymphoblastic B-cell infiltrate that displayed a latency type III EBV gene expression profile similar to PCNSL that develops in some immune-deficient patients. Radiation (1600 cGy) of lymphoblastoid B-cell lines resulted in up-regulation of the EBV thymidine kinase (EBV-TK) transcript and sensitization of these cells to drug-induced apoptosis using nucleoside analogs. Enhanced expression of EBV-TK mRNA in EBV(+) PCNSL tumors by radiation therapy occurred in a dose-dependent fashion. In vivo trials using the nude rat PCNSL model demonstrated significantly improved mean survival time (MST) with single fraction whole-brain radiotherapy (WBRT) and antiviral therapy consisting of zidovudine (AZT) and ganciclovir (GCV; MST 41.3 +/- 3.3 days; P = 0.05), compared with either antiviral therapy (MST 32.1 +/- 1.1 days) or WBRT alone (MST 22 +/- 0.8 days). We found constitutive and abundant EBV-TK mRNA expression in a stereotactic core biopsy specimen from a solid organ transplant patient with EBV(+) PCNSL. Withdrawal of immunosuppression did not result in disease regression. This patient achieved a complete response after therapy with high-dose AZT and GCV in the absence of WBRT, and remains in remission on oral maintenance AZT/GCV therapy 3 years after diagnosis. These results suggest that antiviral therapies can be effectively explored in vivo using a preclinical animal model of human EBV(+) PCNSL with subsequent translation to patients with EBV(+) PCNSL.

Successful treatment of posttransplantation lymphoproliferative disorder (PTLD) following renal allografting is associated with sustained CD8(+) T-cell restoration.

Posttransplantation lymphoproliferative disorder (PTLD) is a life-threatening Epstein-Barr virus (EBV)-associated B-cell malignancy occurring in 1% to 2% of renal transplantation patients. Host- and PTLD-related factors determining the likelihood of tumor response following reduction of immune suppression (IS) and antiviral therapy remain largely unknown. Standard therapy for PTLD is not well established. Eleven consecutive renal transplantation patients who developed EBV-positive PTLD 8 to 94 months after allografting were uniformly treated with acyclovir and IS reduction. All PTLDs were EBV-positive diffuse large B-cell lymphomas. Ten patients (91%) obtained a durable complete response (CR), and 9 (82%) have remained in continuous CR with a median follow-up of 29 months. Five patients (45%) lost their allograft. Of these, 4 patients had PTLD affecting the transplanted kidney. Peripheral blood CD8(+) T cells increased significantly (P =.0078) from baseline in 8 responders available for analysis. One of 2 patients whose absolute CD8(+) T-cell count subsequently dropped to baseline after IS reduction relapsed. The expanded CD8(+) T cells from 2 responders specifically recognized an immunodominant peptide from the EBV lytic gene BZLF-1. Another lytic EBV gene, thymidine kinase, was expressed in all 8 PTLDs tested. IS reduction and antiviral therapy for PTLD after renal transplantation is a highly successful therapeutic combination, but the risk of graft rejection is significant, particularly in patients with PTLD involving the renal allograft. A sustained expansion of CD8(+) T cells and a cellular immune response to EBV lytic antigens may be important for PTLD clearance in renal transplantation patients.