PurposeIndoximod is an oral inhibitor of the indoleamine 2,3-dioxygenase pathway, which causes tumor-mediated immunosuppression. Primary endpoints were maximum tolerated dose (MTD) and toxicity for indoximod in patients with advanced solid tumors. Secondary endpoints included response rates, pharmacokinetics, and immune correlates.Experimental DesignOur 3+3 phase I trial comprised 10 dose levels (200, 300, 400, 600, and 800 mg once/day; 600, 800, 1200, 1600, and 2000 mg twice/day). Inclusion criteria were measurable metastatic solid malignancy, age ≥18 years, and adequate organ/marrow function. Exclusion criteria were chemotherapy ≤ 3 weeks prior, untreated brain metastases, autoimmune disease, or malabsorption.ResultsIn 48 patients, MTD was not reached at 2000 mg twice/day. At 200 mg once/day, 3 patients previously treated with checkpoint inhibitors developed hypophysitis. Five patients showed stable disease >6 months. Indoximod plasma AUC and Cmax plateaued above 1200mg. Cmax (∼12 μM at 2000 mg twice/day) occurred at 2.9 hours, and half-life was 10.5 hours. C reactive protein (CRP) levels increased across multiple dose levels.ConclusionsIndoximod was safe at doses up to 2000 mg orally twice/day. Best response was stable disease >6 months in 5 patients. Induction of hypophysitis, increased tumor antigen autoantibodies and CRP levels were observed.
The purpose of this study is to determine the extent of nerve involvement and to study the effect of corticosteroids combined with multidrug therapy on nerve damage in leprosy patients using sensory and motor nerve conduction studies. A cohort of 365 untreated multibacillary leprosy patients were prospectively studied using sensory and motor nerve conduction studies on upper and lower limb nerves. They were subgrouped as those to be treated with 12-week regimen of corticosteroids for reaction and/or neuritis or silent neuropathy of <6 months duration along with 12-month multidrug therapy (group A), and those with no reaction were treated with multidrug therapy only (group B). Analysis was performed using SPSS version 10.0. Significance of association was tested using chi(2) test. At registration, abnormality by nerve conduction studies was seen in 92% of patients and majority (65%) showing involvement of more than five sensory and motor nerves. Sensory nerve abnormalities were higher (52%) than motor (37%) (P < 0.001). Affection of sensory and motor nerves was higher in group A (P < 0.001). Notably, 40% nerves in group B also showed impairment at 0 month. This implies that almost all patients showed abnormal nerve conduction studies at onset regardless of reaction, proving nerve damage is more widespread than envisaged. At 18 months, overall percentile deterioration (23%) of nerves was higher than improvement (9%) (P < 0.001) indicating that corticosteroids combined with multidrug therapy failed to significantly improve the nerve status. Sensory nerve (57%) affection was significantly higher than motor (46%) (P < 0.001). Moreover, percentile deterioration of sensory nerves was higher in group A (P < 0.001) implying corticosteroids is not very efficacious in the prevention or reversal of nerve damage. Electrophysiological tests provide valuable information for detecting nerve function impairment and evaluating appropriate therapeutic regimens.
BackgroundIndoleamine 2, 3-dioxygenase is an enzyme that causes immunosuppression in tumors. Indoximod inhibits the indoleamine 2, 3-dioxygenase pathway and enhances immunologic responses to dendritic cell (DC) vaccines preclinically. Adenovirus p53 (Ad.p53) is used to generate DC vaccines against p53. A phase-1/2 trial of indoximod with Ad.p53-DC vaccine was conducted.Materials and MethodsThe phase-1 study combined 7 indoximod dose levels with < 6 Ad.p53-DC vaccinations every 2 weeks. Primary endpoints were maximum-tolerated dose in phase 1 and objective response in phase 2. Flow cytometry measured immune responses.ResultsThirty-nine patients were treated. In combination with Ad.p53-DC vaccine, the maximum-tolerated dose of indoximod was 1600 mg twice daily. Attributable toxicities were grade 1–2. Best response was stable disease in 4 patients. Immunologic responses were detected in 7 out of 23 evaluable patients. Median progression-free survival was 13.3 weeks (95% confidence interval, 12.97–21.85) and median overall survival was 20.71 weeks (95% confidence interval, 25.75–46.15). Nine out of 22 patients (40%) benefitted from chemotherapy after vaccination. Median overall survival in chemotherapy responders was 69.4 weeks (30.1–122.1).ConclusionsIndoximod 1600 mg twice daily with Ad.p53-DC was well tolerated. There may have been a chemosensitization effect. Future trials should explore combining this treatment with chemotherapy.
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