Toxicology Evaluation of Drugs Administered via Uncommon Routes: Intranasal, Intraocular, Intrathecal/Intraspinal, and Intra-Articular.

As the need for nasal, ocular, spinal, and articular therapeutic compounds increases, toxicology assessments of drugs administered via these routes play an important role in human safety. This symposium outlined the local and systemic evaluation to support safety during the development of these drugs in nonclinical models with some case studies. Discussions included selection of appropriate species for the intended route; conducting nonclinical studies that closely mimic the intended use with adequate duration; functional assessment, if deemed necessary; evaluation of local tissues with special histological staining procedure; and evaluations of safety margins based on local and systemic toxicity.

RNAi-based treatment for neovascular age-related macular degeneration by Sirna-027.

PURPOSE: To assess the safety, tolerability, pharmacokinetics, and dose-limiting toxicity of single intravitreal injection of Sirna-027, a small interfering RNA targeting vascular endothelial growth factor receptor-1, in patients with choroidal neovascularization (CNV) resulting from neovascular age-related macular degeneration (AMD). Secondary objectives included assessment of anatomic changes in retinal thickness, size of CNV, and changes in visual acuity. DESIGN: Prospective, open-label, single-dose, dose-escalation phase 1 study. METHODS: Twenty-six eyes of 26 patients with a median age of 82 years and CNV resulting from AMD who had previous treatments with other therapies were treated at 2 academic retinal practices. Patients received a single dose of Sirna-027 (100, 200, 400, 800, 1200, or 1600 microg/eye). Blood was sampled for pharmacokinetic analysis at 1, 4, and 24 hours after injection and on day 7. Patients underwent ophthalmic examinations including visual acuity, fluorescein angiography, and optical coherence tomography at screening and days 7, 14, 28, and 84. The main outcome measures were adverse reactions and dose-limiting toxicities. RESULTS: Intravitreal injection of a single dose of Sirna-027 from 100 to 1600 microg was well tolerated in patients with AMD, with no dose-limiting toxicity found. Adverse events were mild to moderate in severity. Adjusted mean foveal thickness decreased within 2 weeks after study treatment. The decrease was most pronounced in the 100- and 200-microg doses. CONCLUSIONS: A single intravitreal dose of Sirna-027 up to 1600 microg/eye was well tolerated in patients with CNV resulting from neovascular AMD that had been refractory to other therapies. Stabilization or improvement in visual acuity and foveal thickness was observed. No dose-response or dose-limiting effects were noted.

Carcinogenicity assessments of biotechnology-derived pharmaceuticals: a review of approved molecules and best practice recommendations.

An important safety consideration for developing new therapeutics is assessing the potential that the therapy will increase the risk of cancer. For biotherapeutics, traditional two-year rodent bioassays are often not scientifically applicable or feasible. This paper is a collaborative effort of industry toxicologists to review past and current practice regarding carcinogenicity assessments of biotherapeutics and to provide recommendations. Publicly available information on eighty marketed protein biotherapeutics was reviewed. In this review, no assessments related to carcinogenicity or tumor growth promotion were identified for fifty-one of the eighty molecules. For the twenty-nine biotherapeutics in which assessments related to carcinogenicity were identified, various experimental approaches were employed. This review also discusses several key principles to aid in the assessment of carcinogenic potential, including (1) careful consideration of mechanism of action to identify theoretical risks, (2) careful investigation of existing data for indications of proliferative or immunosuppressive potential, and (3) characterization of any proliferative or immunosuppressive signals detected. Traditional two-year carcinogenicity assays should not be considered as the default method for assessing the carcinogenicity potential of biotherapeutics. If experimentation is considered warranted, it should be hypothesis driven and may include a variety of experimental models. Ultimately, it is important that preclinical data provide useful guidance in product labeling.

Alternative mouse models for carcinogenicity assessment: industry use and issues with pathology interpretation.

The Carcinogenicity Alternative Mouse Models (CAMM) Working Group of the Society of Toxicologic Pathology (STP) surveyed the membership to define current practices and opinions in industry regarding the use of alternative mouse models for carcinogenicity testing. The results of the survey indicated that CAMM are used most often to fulfill a regulatory requirement (e.g., to replace the two-year mouse bioassay) and are being accepted by regulatory agencies. Alternative models are also sometimes used for internal decision making or to address a mechanistic question. The CAMM most commonly used are the p53+/- and rasH2. The rasH2 appears to be the currently accepted model for general carcinogenicity testing. Problems with study interpretation included lack of historic background data, unexpected tumor finding, and tumor identification/characterization of early lesions. Problems with implementation or conduct of the study included extent of the pathology evaluation, numbers of animals, survival, and study duration. Recommendations were developed for, frequency and type of positive control testing, extent of histopathologic examination of test article-treated and positive control animals, current use and future development of diagnostic criteria; increased availability and use of historic data, and use of other genetically modified mice in carcinogenicity testing.

Clinical efficacy of the first metatarsophalangeal joint arthroplasty as a curative procedure for hallux interphalangeal joint wounds in patients with diabetes.

OBJECTIVE: To evaluate the safety and efficacy of first metatarsophalangeal joint arthroplasty compared with standard, nonsurgical management of wounds at the plantar hallux interphalangeal joint in patients with diabetes. RESEARCH DESIGN AND METHODS: We evaluated 41 patients with ulcers classified as University of Texas Grade 1A or 2A at the plantar aspect of the hallux interphalangeal joint using a case-control model [correction]. Case subjects were patients treated with resectional arthroplasty and control subjects received standard nonsurgical care. Both groups received standard off-loading and wound care. Outcomes included time to healing, reulceration, infection, and amputation. RESULTS: The surgery group healed significantly faster than patients in the standard therapy group (standard 67.1 +/- 17.1 versus surgery 24.2 +/- 9.9 days, P = 0.0001), and they had fewer recurrent ulcers (standard 35.0 versus surgery 4.8%, P = 0.02, odds ratio 7.6, 95% CI 1.1-261.7) Both groups had similar rates of infection (standard 38.1 versus surgery 40.0%, P = 0.9) and amputation (standard 10.0 versus surgery 4.8%, P = 0.5). CONCLUSIONS: Results suggest that resectional arthroplasty is a safe and effective procedure to treat wounds of the plantar hallux compared with nonsurgical therapy.