Neuroblastoma (NBL) and medulloblastoma (MB) are aggressive pediatric cancers which can benefit from therapies targeting gangliosides. Therefore, we compared the ganglioside profile of 9 MB and 14 NBL samples by thin layer chromatography and mass spectrometry. NBL had the highest expression of GD2 (median 0.54 nmol GD2/mg protein), and also expressed complex gangliosides. GD2-low samples expressed GD1a and were more differentiated. MB mainly expressed GD2 (median 0.032 nmol GD2/mg protein) or GM3. Four sonic hedgehog-activated (SHH) as well as one group 4 and one group 3 MBs were GD2-positive. Two group 3 MB samples were GD2-negative but GM3-positive. N-glycolyl neuraminic acid-containing GM3 was neither detected in NBL nor MB by mass spectrometry. Furthermore, a GD2-phenotype predicting two-gene signature (ST8SIA1 and B4GALNT1) was applied to RNA-Seq datasets, including 86 MBs and validated by qRT-PCR. The signature values were decreased in group 3 and wingless-activated (WNT) compared to SHH and group 4 MBs. These results suggest that while NBL is GD2-positive, only some MB patients can benefit from a GD2-directed therapy. The expression of genes involved in the ganglioside synthesis may allow the identification of GD2-positive MBs. Finally, the ganglioside profile may reflect the differentiation status in NBL and could help to define MB subtypes.

BACKGROUND: Racotumomab is a therapeutic vaccine based on a monoclonal anti-idiotypic antibody developed by the Molecular Immunology Center in Havana, Cuba, that is registered in Cuba and Argentina for treatment of non-small cell lung cancer. It induces a specific humoral and cellular immune response against the N-glycolyl GM3 (NeuGcGM3) ganglioside present in tumor cells, thereby provoking the death of these cells.
OBJECTIVE: Evaluate racotumomab vaccine use as switch maintenance and second-line therapy for patients with inoperable non-small cell lung cancer in routine clinical practice, outside the framework of clinical studies, and assess the overall survival, stage-specific survival and safety in these patients.
METHODS: A descriptive, retrospective study was carried out in patients diagnosed with non-small cell lung cancer not suitable for surgical treatment, who received racotumomab as a part of switch maintenance or second-line treatments. Overall survival was defined from diagnosis and from the first immunization, until death.
RESULTS: We included 71 patients treated with racotumomab, 57.7% (41/71) of whom were in stages IIIB and IV of non-small cell lung cancer. Of the patients, 84.5% (60/71) had no adverse events, and 15.5% (11/71) had mild adverse reactions. The median overall survival was 24.5 months, calculated from the first immunization, 17.2 months for those who received racotumomab as switch maintenance and 6.8 months for patients who had progressed after the first line of treatment.
CONCLUSIONS: Racotumomab in routine clinical practice prolonged overall survival in patients with non-small cell lung cancer treated in switch maintenance, and in stage IV patients who received the treatment as second-line therapy. The vaccine was well tolerated.

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.

BACKGROUND: Pediatric neuroectodermal malignancies express N-glycolylated gangliosides including N-glycolyl GM3 (NeuGcGM3) as targets for immunotherapy.
METHODS: 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.
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.

Immunotherapy has been studied for many years in lung cancer without significant results, making the majority of oncologists quite skeptical about its possible application for non-small cell lung cancer treatment. However, the recent knowledge about immune escape and subsequent \'cancer immunoediting\' has yielded the development of new strategies of cancer immunotherapy, heralding a new era of lung cancer treatment. Cancer vaccines, including both whole-cell and peptide vaccines have been tested both in early and advanced stages of non-small cell lung cancer. New immunomodulatory agents, including anti-CTLA4, anti-PD1/PDL1 monoclonal antibodies, have been investigated as monotherapy in metastatic lung cancer. To date, these treatments have shown impressive results of efficacy and tolerability in early clinical trials, leading to testing in several large, randomized Phase III trials. As these results will be confirmed, these drugs will be available in the near future, offering new exciting therapeutic options for lung cancer treatment.

Racotumomab is a murine gamma-type anti-idiotype monoclonal antibody that specifically induces an antibody response against Neu-glycolyl GM3 ganglioside (NeuGcGM3), which is overexpressed in several solid tumors. It is adjuvanted with aluminum hydroxide for intradermal administration as a cancer vaccine (racotumomab-Alum, known commercially as Vaxira®). Racotumomab is currently being evaluated for a number of cancer indications, including melanoma, breast and lung cancer. In early clinical trials, racotumomab demonstrated high immunogenicity and low toxicity and it advanced to further clinical testing as a treatment for patients with non-small cell lung cancer (NSCLC). On the basis of promising results in a phase II/III study, racotumomab was launched in 2013 in Cuba and Argentina as an intradermal injection for the treatment of patients with advanced stage NSCLC.

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.

Immunotherapy targeting ganglioside antigens is a powerful tool for the treatment of high risk neuroblastoma. However, only treatment with anti-GD2 antibodies has been used in clinical practice and other options may be pursued. We report the use of racotumomab, an anti-idiotype vaccine against N-glycolyl neuraminic acid (NeuGc)- containing gangliosides, eliciting an immune response in a child with relapsed neuroblastoma expressing the NeuGcGM3 ganglioside.

Active immunotherapy is an interesting field from the industry\'s perspective and in the last years, regulatory agencies and the medical community have showed renewed expectations and interest in cancer vaccines. The development of new immune therapies offers many challenges, and this is reflected in the small number of phase III trials showing clear benefits. Traditional concepts applied in clinical trials for the development of chemotherapeutic agents may be inadequate for immunotherapies and a new paradigm is emerging. It is possible that organized efforts and funding will accelerate the development of therapeutically effective cancer vaccines. This article reviews the attributes of cancer vaccines which make them attractive from the industry\'s perspective, and focuses especially in the characteristics of Racotumomab, an anti-idiotype antibody vaccine.