Intrathecal administration of an anti-ganglioside antibody results in specific accumulation within meningeal neoplastic xenografts in nude rats

[Leptomeningeal meningitis related to breast cancer overexpressing HER2: is there a place for a more specific treatment?]

Leptomeningeal metastases are very commonly associated with breast cancer. The prognosis is very poor in the short term with an overall median survival less than 6 months. Based on pragmatic and historical considerations intrathecal chemotherapy (IT) are considered to be the adequate treatment. However overall results are disappointing. Despite specific and symptomatic treatment, improvement in survival and quality of life remains very modest, highlighting the importance for ongoing research for developing new molecules or on improving the use a better use of those available today. The incidence of leptomeningeal metastases is particularly marked in cases of overexpression of HER2. The main hypothesis is there may be a better control of extra-cerebral localisations with trastuzumab therefore intra-cerebral recurrences may be encountered preferentially as they are not reached by this high molecular weight monoclonal antibody (148  kD). Analyses performed in the cerebrospinal fluid following intravenous trastuzumab showed extremely low levels of the antibody and support the hypothesis that leptomeningeal metastasis of HER2-overexpressing breast carcinoma remain potentially sensitive to HER2-type receptor inhibition by a target agent under the condition of by-passing the meningeal blood brain barrier. Intra-ventricular or IT administered with trastuzumab would reach high loco-regional therapeutic concentrations in the cerebro-meningeal without risk for normal non-expressing HER2 leptomeningeal tissue. This strategy has been successfully tested on several animal models. A limited number of administrations in humans have been described in the literature, with weekly doses up to 100  mg. No specific toxicity has been described and some data suggest a potential benefit in survival despite the real difficulties for adequate interpretations. Furthermore, a multicentric phase I-II clinical trial, of which the Curie institute is the sponsor and investigating the intra-thecal administration and the efficacy of the trastuzumab will begin very soon. More studies are needed to measure the exact impact of small molecule inhibitors of tyrosine kinase on the leptomeningeal localizations.

Antibody-based immunotherapy in high-risk neuroblastoma

Although great advances have been made in the treatment of low- and intermediate-risk neuroblastoma in recent years, the prognosis for advanced disease remains poor. Therapies based on monoclonal antibodies that specifically target tumour cells have shown promise for treatment of high-risk neuroblastoma. This article reviews the use of monoclonal antibodies either as monotherapy or as part of a multifaceted treatment approach for advanced neuroblastoma, and explains how toxins, cytokines, radioactive isotopes or chemotherapeutic drugs can be conjugated to antibodies to enhance their effects. Tumour resistance, the development of blocking antibodies, and other problems hindering the effectiveness of monoclonal antibodies are also discussed. Future therapies under investigation in the area of immunotherapy for neuroblastoma are considered.

Phase I study of targeted radioimmunotherapy for leptomeningeal cancers using intra-Ommaya 131-I-3F8

PURPOSE

Tumors metastasizing to the CNS and leptomeninges (LM) are associated with significant mortality. We tested the toxicity, pharmacokinetics, and dosimetry of intraventricular iodine-131-labeled monoclonal antibody 3F8 (131I-3F8) targeting GD2-positive CNS/LM disease in a phase I clinical trial.

PATIENTS AND METHODS

Adequate CSF flow was determined by pretreatment indium-111-DTPA studies. Fifteen patients received a tracer (1 to 2 mCi) and therapeutic injection (10 to 20 mCi) of intra-Ommaya 131I-3F8. 131I-3F8 pharmacokinetics were studied by serial CSF and blood samplings. Dosimetry was based on pharmacokinetics and region of interest (ROI) analyses on whole-body gamma camera scans. Tumor response was determined by clinical, radiographic, and cytologic criteria.

RESULTS

Total absorbed CSF dose was 1.12 to 13.00 Gy by sampling and 1.00 to 13.70 Gy by ROI data. Average dosimetry ratio (Gy/mCi) of the therapy/tracer administration was 0.88 (+/- 0.58) and 1.08 (+/- 0.66) based on CSF pharmacokinetics and ROI analysis, respectively. CSF half-life by sampling was 3 to 12.9 hours. Toxicities included self-limited headache, fever, and vomiting. Dose-limiting toxicity was reached at the 20-mCi dose, when transient elevations in intracranial pressure and chemical meningitis were seen. Three of 13 assessable patients achieved objective radiographic and/or cytologic responses. No late toxicities have been seen in two patients who remain in remission off therapy for more than 3.5 years.

CONCLUSION

Intra-Ommaya 131I-3F8 was generally well tolerated; the maximum-tolerated dose was 10 mCi. A high CSF-to-blood ratio was achieved. Tracer studies reliably predicted the therapeutic dose to the CSF. Radioimmunoconjugates targeting GD2 may have clinical utility in the treatment of CNS/LM malignancies.

New agents for intrathecal administration

Intrathecal administration of chemotherapy, with or without radiation therapy, is the primary treatment modality for the prevention and treatment of central nervous system (CNS) metastases in patients with leukemia or lymphoma. Although this treatment strategy has been very effective for patients with hematological malignancies, currently available intrathecal agents are relatively ineffective for patients with neoplastic meningitis resulting from an underlying solid or CNS tumor effective. This article provides an overview of some of the practical considerations and limitations associated with intrathecal chemotherapy, and is followed by a comprehensive review of some of the preclinical and early phase clinical trials of novel anticancer agents and treatment strategies using the intrathecal route.

Treatment of neuroblastoma meningeal carcinomatosis with intrathecal application of alpha-emitting atomic nanogenerators targeting disialo-ganglioside GD2

Labeling of specific antibodies with bifunctional chelated Actinium-225 ((225)Ac; an alpha generator) allows the formation of new, highly potent and selective alpha-emitting anticancer drugs. We synthesized and evaluated a radioimmunoconjugate based on 3F8, an IgG(3) antibody that specifically binds to ganglioside GD2, which is overexpressed by many neuroectodermal tumors including neuroblastoma. The (225)Ac-1,4,7,10-tetra-azacylododecane (DOTA)-3F8 construct was evaluated for radiochemical purity and sterility, immunoreactivity, cytotoxicity in vitro, induction of apoptosis on GD2-positive cells, as well as for pharmacological biodistribution and metabolism of the (225)Ac generator and its daughters in a nude mouse xenograft model of neuroblastoma. The (225)Ac-3F8 showed an IC(50) of 3 Bq/ml (80 pCi/ml) on the neuroblastoma cell line, NMB7, in vitro. Apoptosis of these cells was not observed. Biodistribution in mice showed specific targeting of a subcutaneous tumor; there was redistribution of the (225)Ac daughter nuclides mainly from blood to kidneys and to small intestine. Toxicity was examined in cynomolgus monkeys. Monkeys injected with 1 to 3 doses of intrathecal (225)Ac-3F8 radioimmunoconjugate (80 to 150 kBq/kg total dose) did not show signs of toxicity based on blood chemistry, complete blood counts, or by clinical evaluations. Therapeutic efficacy of intrathecal (225)Ac-3F8 was studied in a nude rat xenograft model of meningeal carcinomatosis. The (225)Ac-3F8 treatment improved survival 2-fold from 16 to 34 days (P = 0.01). In conclusion, in vivo alpha generators targeted by 3F8 warrant additional study as a possible new approach to the treatment of carcinomatous meningitis.

Antibody directed against GD(2) produces mechanical allodynia, but not thermal hyperalgesia when administered systemically or intrathecally despite its dependence on capsaicin sensitive afferents

Anti-GD(2) antibodies have been shown to be effective for immunotherapy of neuroblastoma and other GD(2) enriched malignancies. Infusion of anti-GD(2) antibodies frequently causes spontaneous pain and allodynia for the duration of the immunotherapy and occasionally longer lasting neuropathic pain. Bolus intravenous injection of anti-GD(2) in rats initiates mechanical allodynia as measured by withdrawal threshold of the hindpaws. In this study, thermal thresholds were measured prior to and for up to 6 h following systemic anti-GD(2) administration in adult rats. In addition, both thermal and mechanical thresholds were tested following intrathecal administration of anti-GD(2) and IgG(2a). Murine anti-GD(2) elicited mechanical allodynia when administered into either the vasculature or the intrathecal space. Effective systemic doses were 1--3 mg/kg as previously shown. Intrathecally, optimal doses ranged from 0.01 to 0.1 ng; a higher dose was ineffective. Thermal hyperalgesia was not observed via either route of administration. Intrathecal pretreatment 48--72 h prior to the experiment with capsaicin at doses sufficient to cause a 50% depletion of dorsal horn CGRP, caused a total blockade of the mechanical allodynia indicating an involvement of peptidergic fine afferent fibers. It is likely that the antibody reacts with an antigen on peripheral nerve and/or myelin to initiate its effect. The lack of observed thermal hyperalgesia is surprising especially in light of the capsaicin-associated blockade, however, it is consistent with several other immune system related models of pain.

Monoclonal antibody-based therapy of neuroblastoma

The curative potential of mAbs in the treatment of patients with metastatic neuroblastoma is increasingly evident. The idiotype network appears to represent one component of a complex mechanism for success with mAb-based immunotherapy. Ongoing strategies to modify or reconstruct mAbs, to engage them with cytokines, or to unite them with T cells open new avenues for harnessing the unique forces of the immune system against some of the most deadly pediatric cancers.

Feasibility of intraventricular administration of etoposide in patients with metastatic brain tumours

As the systemic administration of etoposide is effective in the treatment of relapsed and metastatic brain tumours, a pilot trial was designed to study the feasibility of intraventricular administration of etoposide in such patients. 14 patients aged 2.1 to 33.2 years were treated with intraventricular etoposide simultaneously with either oral or intravenous chemotherapy with trofosfamide or carboplatin and etoposide. In 59 courses (1-12/patient) 0.5 mg etoposide was administered daily via an indwelling subcutaneous reservoir for 5 consecutive days every 2-5 weeks over a period of 0-11 months. During 15 courses in 5 patients serial CSF samples were obtained and etoposide levels were determined by reversed-phase HPLC. Side effects included transient headache and bacterial meningitis, each during 2 courses. Pharmacokinetic data analysis in the CSF (11 courses, 4 patients) revealed a terminal half-life of 7.4+/-1.2 hours and an AUC of 25.0 +/- 9.5 microg h ml(-1)(mean +/- standard deviation). The volume of distribution at steady state and total clearance exhibited a large interindividual variability with mean values of 0.16 l and 0.46 ml min(-1)respectively. Intraventricularly administered etoposide is well tolerated. CSF peak levels exceed more than 100-fold those achieved with intravenous infusions. Further studies should be focused on optimizing the dose and schedule and on determining the effectiveness of intraventricularly administered etoposide.

Treatment of neoplastic meningeal xenografts by intraventricular administration of an antiganglioside monoclonal antibody, 3F8

Leptomeningeal (LM) neoplastic metastases are painful, debilitating and inevitably lethal. Intrathecal (IT) anti-tumor antibodies may have therapeutic potential. We evaluated 3F8, an anti-G(D2) murine IgG(3) monoclonal antibody (MAb) in the treatment of human melanoma (SKMEL-1) and neuroblastoma (NMB7) xenografts in athymic rats. Both tumors were lysed efficiently in vitro by 3F8 in the presence of rat neutrophils or rat complement. Antibody-dependent cellular cytotoxicity (ADCC) was not augmented by recombinant human GM-CSF (rhGM-CSF), rhG-CSF, recombinant rat MIP-2 (rrMIP-2) or lipopolysaccharide (LPS). In vivo, continuous intraventricular administration of 3F8 and LPS prevented tumor engraftment, retarded tumor growth and eradicated 3-day-old established xenografts whereas 3F8 alone, LPS alone or F(ab)'(2) plus LPS had no or only marginal effects. Tumor establishment in brain was completely prevented in 36% of animals implanted with SKMEL-1 and 65% of animals implanted with NMB7. Twenty percent of established xenografts around the brain were eradicated but all animals had persistent tumor in the lumbosacral meninges despite treatment. Continuous intraventricular infusion of LPS produced a variable polymorphonuclear (PMN) pleocytosis that was dose-dependent. Continuous intraventricular infusion of 3F8 produced immunohistochemically detectable attachment to 86% of persistent brain deposits of tumor but <1% of spinal lumbosacral deposits. We conclude that regional therapy with anti-G(D2) MAb could target neutrophils to inhibit LM tumor growth. However, optimal activation and mobilization of neutrophils into the cerebrospinal fluid (CSF) and improved penetration of MAb to tumor sites remain critical variables.