Jon T. Holmlund

Targeting Bcl-2 family members with the BH3 mimetic AT-101 markedly enhances the therapeutic effects of chemotherapeutic agents in in vitro and in vivo models of B-cell lymphoma

Overexpression of antiapoptotic members of the Bcl-2 family are observed in approximately 80% of B-cell lymphomas, contributing to intrinsic and acquired drug resistance. Nullifying antiapoptotic function can potentially overcome this in-trinsic and acquired drug resistance. AT-101 is a BH3 mimetic known to be a potent inhibitor of antiapoptotic Bcl-2 family members including Bcl-2, Bcl-X(L), and Mcl-1. In vitro, AT-101 exhibits concentration- and time-dependent cytotoxicity against lymphoma and multiple myeloma cell lines, enhancing the activity of cytotoxic agents. The IC(50) for AT-101 is between 1 and 10 microM for a diverse panel of B-cell lymphomas. AT-101 was synergistic with carfilzomib (C), etoposide (E), doxorubicin (D), and 4-hydroxycyclophosphamide (4-HC) in mantle cell lymphoma (MCL) lines. In a transformed large B-cell lymphoma line (RL), AT-101 was synergistic when sequentially combined with 4-HC, but not when both drugs were added simultaneously. AT-101 also induced potent mitochondrial membrane depolarization (Delta Psi m) and apoptosis when combined with carfilzomib, but not with bortezomib in MCL. In severe combined immunodeficient (SCID) beige mouse models of drug-resistant B-cell lymphoma, 35 mg/kg per day of AT-101 was safe and efficacious. The addition of AT-101 to cyclophosphamide (Cy) and rituximab (R) in a schedule-dependent manner enhanced the efficacy of the conventional therapy.

The effects of treatment with interleukin-1α on platelet recovery after high-dose carboplatin

Background Thrombocytopenia is a frequent side effect of cancer chemotherapy and commonly limits attempts to escalate drug doses. To determine whether interleukin-1α could ameliorate carboplatin-induced thrombocytopenia, we combined it with high-dose carboplatin in 43 patients with advanced neoplasms. Methods High-dose carboplatin (800 mg per square meter of body-surface area) was administered alone to a control group. Subsequent patients were randomly assigned to receive the same dose of carboplatin with interleukin-1α, administered either before or after carboplatin. Interleukin-1α was given intravenously at a dose of 0.03, 0.1, or 0.3 μg per kilogram of body weight per day for five days. Results Carboplatin alone consistently produced thrombocytopenia with a median nadir of 19,000 platelets per cubic millimeter and a median of 10 days with less than 100,000 platelets per cubic millimeter. All 15 patients receiving interleukin-1α before carboplatin had similar findings. In contrast, 5 of the 15 patients...

Treatment of cancer patients with ex vivo anti-CD3-activated killer cells and interleukin-2.

PURPOSE This study describes the physiologic and biologic effects resulting from the adoptive transfer of ex vivo anti-CD3-stimulated T-killer cells (T-AK) to patients with advanced cancer in combination with interleukin-2 (IL-2). METHODS Autologous peripheral-blood mononuclear cells were obtained by leukapheresis and stimulated ex vivo with anti-CD3. The stimulated cells were reinfused at one of three dose levels on the next day (5 x 10(9), 7.5 x 10(9), and 1 x 10(10)). Cell administration was followed by IL-2 given by bolus and continuous infusion (1.5 x 10(6) U/m2 and 3.0 x 10(6) U/m2, respectively) for 7 days, or continuous infusion alone (3.0 x 10(6) U/m2) for 14 days. RESULTS Pronounced leukocytosis and atypical lymphocytosis were observed with individual values as high as 80,000 and 50,000 cells/microL, respectively. The other major clinical sequelae included a marked lactic acidosis with bicarbonate levels as low as 4.0 mmol/L in some patients, and prolongation of the prothrombin time (PT) and partial thromboplastin time (PTT) due to decreases in clotting factors VII, IX, and X. Antithrombin III levels were also reduced. Hypotension associated with increased serum nitrate and neopterin levels was observed. These toxicities were accompanied by increases in hepatocellular enzymes and creatinine previously described with IL-2. These events occurred at a time when the number of circulating T-AK cells reached their peak. The amount of bolus IL-2 correlated with increases in WBC count (P = .0311), atypical lymphocytes (P = .0241), PT (P = .0006), and PTT (P = .0122). CONCLUSION Substantial in vivo expansion of activated T lymphocytes was induced by a protocol combining ex vivo activation of peripheral-blood cells with anti-CD3 antibody followed by adoptive transfer and IL-2 administration. The synchronous expansion of these T cells superimposed on diminished liver and kidney function from IL-2 can cause profound but reversible metabolic changes.

Phase I study of subcutaneously administered interleukin-2 in combination with interferon alfa-2a in patients with advanced cancer.

PURPOSE Although high-dose interleukin-2 (IL-2) can produce durable remissions in a subset of responding patients with renal cell carcinoma (RCC), this occurs in the setting of significant toxicity. The purpose of this study is to define the maximum-tolerated dosage (MTD) of IL-2 and interferon alfa-2a (IFN alpha-2a) that can be administered chronically on an outpatient basis. PATIENTS AND METHODS Fifty-three patients with advanced cancer of variable histology with good prognostic features were treated in six cohorts. Patients in cohorts one through five received IL-2 (1.5 or 3.0 x 10(6) million units (mU)/m2) Monday through Friday and IFN alpha-2a (1.5 or 3 x 10(6) mU/m2) daily for a 4-week cycle. In cohort six, IFN alpha-2a was given three times a week. Immunologic monitoring, including serum levels of soluble IL-2 receptor (sIL-2R) and neopterin, flow cytometry, and natural killer cell (NK) activity, were measured. Patients were evaluated for toxicity, response, and survival. RESULTS Almost all patients developed grade I/II toxicities commonly associated with cytokine therapy. Symptoms were most severe with the first treatment of each week. Dose-limiting toxicities included grade III fatigue, hypotension, and creatinine elevations. The MTD was 1.5 mU/m2 daily x 5 given subcutaneously repeated weekly for IL-2 and 1.5 mU/m2 daily subcutaneously (dose level 3) for IFN. Six of 25 assessable patients with RCC (24%) achieved a partial response (PR), including four of eight patients who were previously untreated. There were no objective responses in patients with other tumors, including 12 melanoma patients. CONCLUSION IL-2 and IFN alpha-2a can be given with tolerable toxicities on an outpatient basis and shows significant activity in patients with metastatic RCC.

A phase I randomized study of subcutaneous adjuvant IL-2 in combination with an autologous tumor vaccine in patients with advanced renal cell carcinoma

We performed a prospective, randomized study to determine whether subcutaneous administration of interleukin-2 (IL-2) in combination with an autologous renal cell vaccine is feasible and can potentiate antitumor immunity. Seventeen patients with metastatic renal cell carcinoma underwent surgical resection with preparation of an autologous tumor cell vaccine. Patients were vaccinated intradermally twice at weakly intervals with 10(7) irradiated tumor cells plus bacillus Calmette-Guérin, and once with 10(7) tumor cells alone. Patients were randomized to one of three groups: no adjuvant IL-2, low-dose IL-2 (1.2 x 10(6) IU/m2), or high-dose IL-2 (1.2 x 10(7) IU/m2). IL-2 was administered subcutaneously on the day of vaccination and the subsequent 4 days. Immune response was monitored by delayed-type hypersensitivity (DTH) response to tumor cells as compared with normal autologous renal cells. Sixteen of 17 patients received vaccine therapy. Four patients developed cellular immunity specific for autologous tumor cells as measured by DTH responses; two had received no IL-2 and two had received high-dose IL-2. There were two partial responses (PR) noted, both in patients who received high-dose IL-2. One responding patient was DTH(+) and one was negative. A third patient who was DTH(+) after vaccination with no IL-2 had a dramatic PR after receiving IL-2 subcutaneously in a subsequent protocol. Prospective testing of response to recall antigens indicated that only 5 of 12 tested patients were positive, including both clinical responders. These data suggest that subcutaneously administered adjuvant IL-2 does not dramatically augment the immunologic response to autologous renal cell vaccines as determined by the development of tumor-specific DTH response.

Influence of interleukin-2 regimens on circulating populations of lymphocytes after adoptive transfer of anti-CD3-stimulated T cells: results from a phase I trial in cancer patients.

The adoptive transfer of anti-CD3-stimulated T killer (T-AK) cells was tested with different bolus and infusional interleukin-2 (IL-2) regimens, and anti-CD3 stimulation procedures to determine immunologic and antitumor effects in patients with a variety of advanced cancers. Indium-111 labeling was used to observe traffic patterns of the infused T-AK. Autologous peripheral blood mononuclear cells were obtained by leukapheresis. Cyclophosphamide (300 mg/m2) was given to most patients immediately after leukapheresis. The harvested cells were activated ex vivo with anti-CD3 overnight or for 4 days, at which time cells were reinfused and an IL-2 regimen was begun. Treatment was repeated 28 days later. This treatment regimen induced significant increases in leukocytes, lymphocytes, and eosinophils in patients in most treatment cohorts. Circulating lymphocytes were predominantly CD3+ T cells with preferential expansion of the CD8+ subset. Patients receiving cells stimulated in vitro for 4 days had significant T-cell lymphocytosis with either infusional or bolus plus infusional IL-2 regimens. T-cell viability was decreased in culture after a second 4-day stimulation with anti-CD3 at day 28; this decrease could be prevented by adding IL-2 to the culture media. Cells stimulated overnight required both bolus and infusional IL-2 to show an atypical lymphocytosis in vivo. Overnight-stimulated T-AK did not show decreases in in vitro viability at the day 28 restimulation. Indium-III-labeled cells trafficked to the liver, spleen, and bone marrow. No increase in uptake was observed in tumor deposits. There were 2 patients with partial responses, 5 with minor responses, 19 with stable disease, and 88 with progressive disease. The length of in vitro anti-CD3 stimulation, and the dose and timing of IL-2 administration in vivo results in different circulating leukocyte populations after adoptive T-AK infusion. Generally, the CD8+ T-cell subset was preferentially expanded by this treatment approach. Repeated ex vivo stimulation with anti-CD3 may cause cell death.