Antibody-dependent cell-mediated cytotoxicity induced by active immunotherapy based on racotumomab in non-small cell lung cancer patients.

Antitumor strategies based on positive modulation of the immune system currently represent therapeutic options with prominent acceptance for cancer patients' treatment due to its selectivity and higher tolerance compared to chemotherapy. Racotumomab is an anti-idiotype (anti-Id) monoclonal antibody (mAb) directed to NeuGc-containing gangliosides such as NeuGcGM3, a widely reported tumor-specific neoantigen in many human cancers. Racotumomab has been approved in Latin American countries as an active immunotherapy for advanced non-small cell lung cancer (NSCLC) treatment. In this work, we evaluated the induction of Ab-dependent cell-mediated cytotoxicity (ADCC) in NSCLC patients included in a phase III clinical trial, in response to vaccination with racotumomab. The development of anti-NeuGcGM3 antibodies (Abs) in serum samples of immunized patients was first evaluated using the NeuGcGM3-expressing X63 cells, showing that racotumomab vaccination developed antigen-specific Abs that are able to recognize NeuGcGM3 expressed in tumor cell membranes. ADCC response against NeuGcGM3-expressing X63 (target) was observed in racotumomab-treated- but not in control group patients. When target cells were depleted of gangliosides by treatment with a glucosylceramide synthase inhibitor, we observed a significant reduction of the ADCC activity developed by sera from racotumomab-vaccinated patients, suggesting a target-specific response. Our data demonstrate that anti-NeuGcGM3 Abs induced by racotumomab vaccination are able to mediate an antigen-specific ADCC response against tumor cells in NSCLC patients.

A phase II dose-escalation trial of perioperative desmopressin (1-desamino-8-d-arginine vasopressin) in breast cancer patients.

Desmopressin (dDAVP) is a well-known peptide analog of the antidiuretic hormone vasopressin, used to prevent excessive bleeding during surgical procedures. dDAVP increases hemostatic mediators, such as the von Willebrand factor (vWF), recently considered a key element in resistance to metastasis. Studies in mouse models and veterinary trials in dogs with locally-advanced mammary tumors demonstrated that high doses of perioperative dDAVP inhibited lymph node and early blood-borne metastasis and significantly prolonged survival. We conducted a phase II dose-escalation trial in patients with breast cancer, administering a lyophilized formulation of dDAVP by intravenous infusion in saline, 30-60 min before and 24 h after surgical resection. Primary endpoints were safety and tolerability, as well as selection of the best dose for cancer surgery. Secondary endpoints included surgical bleeding, plasma levels of vWF, and circulating tumor cells (CTCs) as measured by quantitative PCR of cytokeratin-19 transcripts. Only 2 of a total of 20 patients experienced reversible adverse events, including hyponatremia (grade 4) and hypersensitivity reaction (grade 2). Reactions were adequately managed by slowing the infusion rate. A reduced intraoperative bleeding was noted with increasing doses of dDAVP. Treatment was associated with higher vWF plasma levels and a postoperative drop in CTC counts. At the highest dose level evaluated (2 µg/kg) dDAVP appeared safe when administered in two slow infusions of 1 µg/kg, before and after surgery. Clinical trials to establish the effectiveness of adjunctive perioperative dDAVP therapy are warranted. This trial is registered on www.clinicaltrials.gov (NCT01606072).

A Phase I Study of the Anti-Idiotype Vaccine Racotumomab in Neuroblastoma and Other Pediatric Refractory Malignancies.

BACKGROUND: Pediatric neuroectodermal malignancies express N-glycolylated gangliosides including N-glycolyl GM3 (NeuGcGM3) as targets for immunotherapy. PROCEDURE: We evaluated the toxicity and maximum tolerated dose and immunological response of racotumomab, an anti-idiotype vaccine targeting NeuGcGM3 through a Phase I study enrolling children with relapsed or resistant tumors expressing NeuGcGM3. MATERIALS AND METHODS: Drug dose was escalated to three levels (0.15-0.25-0.4 mg) of racotumomab administered intradermally. Each drug level included three patients receiving a total of three doses, every 14 days. A confirmation cohort was added to the highest dose level. Antibody response was assessed upon study entry and at 4-week intervals for at least three immunological determinations for each patient. RESULTS: Fourteen patients were enrolled (10 with neuroblastoma, one with retinoblastoma, one with Wilms' tumor, and two with brainstem glioma). Three patients completed the three drug levels and three were enrolled in the confirmation cohort. One patient died of tumor progression before completing the three applications. Racotumomab was well tolerated. The only side effect observed was grade 1-2 toxicity at the injection site. Racotumomab elicited an IgM and/or IgG antibody response directed against NGcGM3 in nine patients and IgM against racotumomab in 11 of 13 evaluable patients. The maximum tolerated dose was not reached and no dose-limiting toxicity was seen. CONCLUSIONS: Racotumomab vaccination has a favorable toxicity profile up to a dose of 0.4 mg, and most patients elicited an immune response. Its activity as immunotherapy for neuroectodermal malignancies will be tested in further clinical trials.

Anti-ganglioside antibodies induced in chickens by an alum-adsorbed anti-idiotype antibody targeting NeuGcGM3.

Racotumomab is a murine anti-idiotype cancer vaccine targeting NeuGcGM3 on melanoma, breast, and lung cancer. In order to characterize the immunogenicity of alum-adsorbed racotumomab in a non-clinical setting, Leghorn chickens were immunized in dose levels ranging from 25 µg to 1600 µg. Racotumomab was administered subcutaneously in the birds' neck with three identical boosters and serum samples were collected before, during and after the immunization schedule. A strong antibody response was obtained across the evaluated dose range, confirming the immunogenicity of racotumomab even at dose levels as low as 25 µg. As previously observed when using Freund's adjuvant, alum-adsorbed racotumomab induced an idiotype-specific response in all the immunized birds and ganglioside-specific antibodies in 60-100% of the animals. In contrast to the rapid induction anti-idiotype response, detection of ganglioside-specific antibodies in responsive animals may require repeated boosting. Kinetics of anti-NeuGcGM3 antibody titers showed a slight decline 2 weeks after each booster, arguing in favor of repeated immunizations in order to maintain antibody titer. Interestingly, the intensity of the anti-NeuGcGM3 response paralleled that of anti-mucin antibodies and anti-tumor antibodies, suggesting that the in vitro detection of anti-ganglioside antibodies might be a surrogate for an in vivo activity of racotumomab. Taken together, these results suggest that Leghorn chicken immunization might become the means to test the biological activity of racotumomab intended for clinical use.

NGcGM3 ganglioside: a privileged target for cancer vaccines.

Active specific immunotherapy is a promising field in cancer research. N-glycolyl (NGc) gangliosides, and particularly NGcGM3, have received attention as a privileged target for cancer therapy. Many clinical trials have been performed with the anti-NGc-containing gangliosides anti-idiotype monoclonal antibody racotumomab (formerly known as 1E10) and the conjugated NGcGM3/VSSP vaccine for immunotherapy of melanoma, breast, and lung cancer. The present paper examines the role of NGc-gangliosides in tumor biology as well as the available preclinical and clinical data on these vaccine products. A brief discussion on the relevance of prioritization of cancer antigens in vaccine development is also included.

Cellular and humoral immune response to N-Glycolyl-GM3 elicited by prolonged immunotherapy with an anti-idiotypic vaccine in high-risk and metastatic breast cancer patients.

In this study, the immunogenicity and toxicity profile of 1E10, an anti-idiotypic vaccine mimicking the N-glycolyl-GM3 ganglioside, was investigated with an extended vaccination protocol. The year-long vaccination scheme consisted of 6 biweekly intradermal injections (induction phase), followed by 10 monthly boosters (maintenance). Nineteen patients with high-risk (stage III) or metastatic breast cancer were vaccinated with different dose levels of 1E10 (0.5, 1, and 2 mg). The humoral and cellular responses to 1E10 and the targeted ganglioside were assessed at baseline and throughout the treatment. Local skin reactions represented the most common adverse event (National Cancer Institute Toxicity Criteria (NCIC) grades I and II), followed by mild flu-like symptoms lasting for 1 to 2 days. Two patients were removed from the study because of vaccine-related hypersensitivity reactions. A third patient was removed from the study after a transient loss of consciousness with uncertain relation to the vaccine. All patients showed a strong antibody response to the targeted ganglioside. In addition, ganglioside-specific T-cell responses were recorded in 5 of 13 evaluable patients. Vaccination with 1E10 was immunogenic and relatively well tolerated. Because similar results were observed with the 3 tested dose levels, the 0.5-mg dose level was selected for future trials.

Active specific immunotherapy of melanoma with a GM3 ganglioside-based vaccine: a report on safety and immunogenicity.

A novel cancer vaccine was obtained by combining GM3 ganglioside with Neisseria meningitidis outer membrane protein complex to obtain very-small-size proteoliposomes (GM3/VSSP). The authors report the results of a phase 1 study of intramuscular administration of GM3/VSSP/Montanide ISA 51 to patients with metastatic melanoma. Twenty-six patients were included in three dose-level cohorts of 120, 240, and 360 mug. The first five doses (induction phase) were given at 2-week intervals, and the remaining four doses were given monthly. Patients were evaluated for dose-related toxicities and antitumor effects. In addition, serum and peripheral blood mononuclear cells were obtained at baseline and throughout treatment to evaluate humoral and cellular immune responses. One episode of severe hypotension and fever was observed in a patient included at the highest dose level. Other toxicities consisted of local reactions at the site of injection and mild fever and chills. Five doses of GM3/VSSP induced an anti-GM3 IgM response in 44% of patients. Serum reactivity was also observed against melanoma cell lines and tumor biopsies. GM3/VSSP was shown to induce very strong in vitro IFNgamma secretion in all evaluated melanoma patients. Furthermore, in one patient IFNgamma secretion was shown to be GM3-specific. A 62% reduction of a mediastinal mass was documented in one patient (partial response), while a second patient benefited from initial disease stabilization followed by tumor reduction in nonmeasurable soft tissue lesions accompanied by vitiligo.