A phase II trial of riluzole, an antagonist of metabotropic glutamate receptor 1 (GRM1) signaling, in patients with advanced melanoma.

Studies demonstrate that GRM, expressed by >60% of human melanomas, may be a therapeutic target. We performed a phase II trial of 100 mg PO bid of riluzole, an inhibitor of GRM1 signaling, in patients with advanced melanoma with the primary endpoint of response rate. Thirteen patients with GRM1-positive tumors were enrolled. No objective responses were observed, and accrual was stopped. Stable disease was noted in six (46%) patients, with one patient on study for 42 weeks. Riluzole was well tolerated, with fatigue (62%) as the most common adverse event. Downregulation of MAPK and PI3K/AKT was noted in 33% of paired tumor biopsies. Hypothesis-generating correlative studies suggested that downregulation of angiogenic markers and increased leukocytes at the active edge of tumor correlate with clinical benefit. Pharmacokinetic analysis showed interpatient variability consistent with prior riluzole studies. Future investigations should interrogate mechanisms of biologic activity and advance the development of agents with improved bioavailability.

Nuclear factor-kappaB modulation in patients undergoing induction chemotherapy for acute myelogenous leukemia.

PURPOSE: Nuclear factor-kappaB (NF-kappaB) is constitutively expressed in many acute myelogenous leukemia (AML) cells and AML stem cells. Ex vivo treatment of AML cells with inhibitors of NF-kappaB results in diminished AML cell survival and enhances the cytotoxic effects of chemotherapeutic agents. The purpose of this study was to determine if standard anti-inflammatory agents modulate AML cell nuclear NF-kappaB when administered in conjunction with induction chemotherapy. EXPERIMENTAL DESIGN: Patients with newly diagnosed AML were treated with dexamethasone, choline magnesium trisalicylate, or both for 24 hours prior to and 24 hours following initiation of standard induction chemotherapy. AML cell nuclear NF-kappaB was measured at baseline, 24, and 48 hours. RESULTS: Choline magnesium trisalicylate +/- dexamethasone decreased nuclear NF-kappaB, whereas dexamethasone alone was associated with an increase in nuclear NF-kappaB in AML cells. CONCLUSIONS: These results show the feasibility of NF-kappaB modulation in conjunction with induction chemotherapy for patients with AML using inexpensive readily available medications. A follow-up study to determine the effects of NF-kappaB modulation on clinical end points is warranted.

A pilot study of allogeneic cellular therapy for patients with advanced hematologic malignancies.

Allogeneic hematopoietic stem cell transplantation provides curative therapy for some patients with advanced hematologic malignancies. Disease response after allogeneic transplant is, at least in part, mediated by donor immune cells. In this report we describe a cellular therapy using haploidentical peripheral blood stem cells administered after very low dose total body irradiation (TBI) (100cGy). The donor cells were anticipated to be rejected, so no graft-versus-host (GVHD) prophylaxis was used. Patients with persistent disease beyond 8 weeks could be further treated with infusions of irradiated haploidentical donor cells. Of the 10 patients enrolled in the study, durable engraftment of allogeneic cells was seen in one patient. Two patients with resistant relapsed acute myelogenous leukemia (AML) had a disease response. Analysis of T cell reactivity from one patient who achieved a complete response but did not have durable engraftment of donor cells indicated that disease response was associated with the generation of host-derived anti-leukemic cytotoxic CD8+ T cells that reacted with an AML-associated proteinase 3 epitope. Results from this patient suggest that allogeneic therapy induced a host anti-tumor response associated with cytotoxic T cells reactive with a low affinity self-antigen.

A phase I clinical trial of 12- O-tetradecanoylphorbol-13-acetate for patients with relapsed/refractory malignancies.

Phorbol esters activate protein kinase C and modulate a variety of downstream cell signaling pathways. 12-O-tetradecanoylphorbol-13-acetate (TPA) is a phorbol ester that induces differentiation or apoptosis in a variety of cell lines at low concentrations. A phase I dose escalation trial of TPA was undertaken for patients with relapsed or refractory malignancies. The starting dose was 0.063 mg/m2 and most patients were treated with an intravenous infusion of TPA on days 1-5 and 8-12 followed by a 2-week rest period prior to retreatment. Thirty-five patients were treated. A biological assay was used to monitor levels of TPA-like activity in the blood after treatment. Serious adverse events included individual episodes of gross hematuria, a grand mal seizure, syncope, and hypotension. Many patients had transient fatigue, mild dyspnea, fever, rigors, and muscular aches shortly after the infusion. Dose-limiting toxicities included syncope and hypotension at a dose of 0.188 mg/m2. Only a single patient had evidence of tumor response. These studies establish 0.125 mg/m2 as the maximally tolerated dose when TPA is administered on this schedule.