A Review on the Efficacy and Safety of Intrathecal Administration of Novel Medications for Leptomeningeal Metastases in Solid Cancers

Leptomeningeal disease (LMD) is a rare and lethal manifestation that may occur in the advanced stages of solid tumors and hematological malignancies. With advances in diagnostic techniques, the detection and confirmation of the presence of LMD have increased. Although its optimal treatment remains a challenge, the use of the intrathecal route for the delivery of novel therapeutics is now considered a promising drug delivery strategy to complement radiation and systemic-based therapies. Although methotrexate, cytarabine, and thiotepa have a long history in the treatment of LMD, other medications have also been shown to be beneficial. In this article, we have reviewed the effects of novel medications administered via the intrathecal route for the treatment of solid tumors. We have searched PubMed, Scopus, and Google Scholar databases till the end of September 2021 using the following keywords: "leptomeningeal disease", "leptomeningeal carcinomatosis", "leptomeningeal metastases", "solid tumors", "solid cancers", and "intrathecal". Our literature findings have uncovered that most studies on LMD, which occurs secondary to solid cancers, are available as 'case reports', and few clinical trials have been conducted to date. Single-drug (monotherapy) or combination drug therapy, administered via the intrathecal route, especially in metastatic breast and lung cancer, has been shown to improve patients' symptoms and overall lifespan, while exhibiting a low and acceptable prevalence of side effects. However, judgments/conclusions about the effectiveness and safety of these drugs still require further clinical evaluation.

Malignant Meningitis Associated with Hydrocephalus

Malignant meningitis (MM) is the diffuse involvement of the leptomeninges by infiltrating cancer cells, most frequently from lung and breast cancers. This review is aimed to discuss the current advances in the diagnosis and management of MM, along with management of MM-associated hydrocephalus. We reviewed the literature using PubMed and Google Scholar search engines, focusing on various recent randomized controlled trials and clinical trials on MM. Given the hallmark multifocal involvement, the clinical symptoms and signs are also random and asymmetric. There are three important pillars for establishing a diagnosis of MM: clinical examination, neuroimaging, and CSF cytological findings. Several factors should be considered in decision-making, including performance status, neurological findings (clinical, MRI, and CSF flow dynamic), and evaluation of the primary tumor (nature and systemic dissemination). Response Assessment in Neuro-Oncology (RANO) working group recommended the objective assessment of disease for evaluating the progression and response to therapy. Pillars of current management are mainly focal irradiation and intrathecal or systemic chemotherapy. Symptomatic hydrocephalus is managed with a ventriculoperitoneal shunt, lumboperitoneal shunt, or endoscopic third ventriculostomy as palliative procedures, providing significant improvement in performance scores in the limited survival time of patients with MM. Studies using novel therapeutic approaches, such as new biological or cytotoxic compounds, are ongoing. Despite the use of all the combinations, the overall prognosis remains grim; therefore, decision-making for treatment should predominantly be based on attaining an optimal quality of life.

Intracerebral administration of CTLA-4 and PD-1 immune checkpoint blocking monoclonal antibodies in patients with recurrent glioblastoma: a phase I clinical trial

Background

Patients with recurrent glioblastoma (rGB) have a poor prognosis with a median overall survival (OS) of 30–39 weeks in prospective clinical trials. Intravenous administration of programmed cell death protein 1 and cytotoxic T-lymphocyte-associated antigen 4 inhibitors has low activity in patients with rGB. In this phase I clinical trial, intracerebral (IC) administration of ipilimumab (IPI) and nivolumab (NIVO) in combination with intravenous administration of NIVO was investigated.

Methods

Within 24 hours following the intravenous administration of a fixed dose (10 mg) of NIVO, patients underwent a maximal safe resection, followed by injection of IPI (10 mg; cohort-1), or IPI (5 mg) plus NIVO (10 mg; cohort-2) in the brain tissue lining the resection cavity. Intravenous administration of NIVO (10 mg) was repeated every 2 weeks (max. five administrations). Next generation sequencing and RNA gene expression profiling was performed on resected tumor tissue.

Results

Twenty-seven patients were enrolled (cohort-1: n=3; cohort-2: n=24). All patients underwent maximal safe resection and planned IC administrations and preoperative NIVO. Thirteen patients (cohort-1: n=3; cohort-2: n=10) received all five postoperative intravenous doses of NIVO. In cohort-2, 14 patients received a median of 3 (range 1–4) intravenous doses. Subacute postoperative neurological deterioration (n=2) was reversible on steroid treatment; no other central nervous system toxicity was observed. Immune-related adverse events were infrequent and mild. GB recurrence was diagnosed in 26 patients (median progression-free survival (PFS) is 11.7 weeks (range 2–152)); 21 patients have died due to progression. Median OS is 38 weeks (95% CI: 27 to 49) with a 6-month, 1-year, and 2-year OS-rate of, respectively, 74.1% (95% CI: 57 to 90), 40.7% (95% CI: 22 to 59), and 27% (95% CI: 9 to 44). OS compares favorable against a historical cohort (descriptive Log-Rank p>0.003). No significant difference was found with respect to PFS (descriptive Log-Rank test p>0.05). A higher tumor mRNA expression level of B7-H3 was associated with a significantly worse survival (multivariate Cox logistic regression, p>0.029).

Conclusion

IC administration of NIVO and IPI following maximal safe resection of rGB was feasible, safe, and associated with encouraging OS.

Trial registration

NCT03233152.

Clinical Trials in Metastatic Uveal Melanoma: Immunotherapy

BACKGROUND

Uveal melanoma (UM) is a rare subtype of melanoma that generally has a poor prognosis once it has metastasized. Clinical trials evaluating immune checkpoint inhibitors (ICIs) in UM have demonstrated response rates lower than those seen in cutaneous melanoma. Despite lower efficacy demonstrated in initial ICI studies, there are a number of ongoing clinical trials investigating novel immunotherapy approaches in UM.

SUMMARY

This review aims to summarize important ongoing clinical trials investigating immunotherapeutic approaches in UM and previous trials that have evaluated a number of immunologic interventions. A thorough clinical trial investigation was conducted through clinicaltrials.gov using the disease search terms "uveal melanoma" and "ocular melanoma," excluding non-immunotherapy-related trials. Here, we report on ICI, vaccine, adoptive T cells, and combination immunotherapy trials in UM.

KEY MESSAGES

There is an increasing effort in the search for new, effective therapies for this difficult-to-treat disease, with immunotherapeutic approaches being of particular interest. Increasing knowledge of UM biology and development of new biomarkers will direct future drug development and trial design.