Subcutaneous Administration of a Monoclonal Antibody to Prevent Malaria.

BACKGROUND: Subcutaneous administration of the monoclonal antibody L9LS protected adults against controlled Plasmodium falciparum infection in a phase 1 trial. Whether a monoclonal antibody administered subcutaneously can protect children from P. falciparum infection in a region where this organism is endemic is unclear. METHODS: We conducted a phase 2 trial in Mali to assess the safety and efficacy of subcutaneous administration of L9LS in children 6 to 10 years of age over a 6-month malaria season. In part A of the trial, safety was assessed at three dose levels in adults, followed by assessment at two dose levels in children. In part B of the trial, children were randomly assigned, in a 1:1:1 ratio, to receive 150 mg of L9LS, 300 mg of L9LS, or placebo. The primary efficacy end point, assessed in a time-to-event analysis, was the first P. falciparum infection, as detected on blood smear performed at least every 2 weeks for 24 weeks. A secondary efficacy end point was the first episode of clinical malaria, as assessed in a time-to-event analysis. RESULTS: No safety concerns were identified in the dose-escalation part of the trial (part A). In part B, 225 children underwent randomization, with 75 children assigned to each group. No safety concerns were identified in part B. P. falciparum infection occurred in 36 participants (48%) in the 150-mg group, in 30 (40%) in the 300-mg group, and in 61 (81%) in the placebo group. The efficacy of L9LS against P. falciparum infection, as compared with placebo, was 66% (adjusted confidence interval [95% CI], 45 to 79) with the 150-mg dose and 70% (adjusted 95% CI, 50 to 82) with the 300-mg dose (P<0.001 for both comparisons). Efficacy against clinical malaria was 67% (adjusted 95% CI, 39 to 82) with the 150-mg dose and 77% (adjusted 95% CI, 55 to 89) with the 300-mg dose (P<0.001 for both comparisons). CONCLUSIONS: Subcutaneous administration of L9LS to children was protective against P. falciparum infection and clinical malaria over a period of 6 months. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT05304611.).

Low-dose intravenous and subcutaneous CIS43LS monoclonal antibody for protection against malaria (VRC 612 Part C): a phase 1, adaptive trial.

BACKGROUND: Human monoclonal antibodies might offer an important new approach to reduce malaria morbidity and mortality. In the first two parts of a three-part clinical trial, the antimalarial monoclonal antibody CIS43LS conferred high protection against parasitaemia at doses of 20 mg/kg or 40 mg/kg administered intravenously followed by controlled human malaria infection. The ability of CIS43LS to confer protection at lower doses or by the subcutaneous route is unknown. We aimed to provide data on the safety and optimisation of dose and route for the human antimalaria monoclonal antibody CIS43LS. METHODS: VRC 612 Part C was the third part of a three-part, first-in-human, phase 1, adaptive trial, conducted at the University of Maryland, Baltimore Center for Vaccine Development and Global Health, Baltimore, MD, USA. We enrolled adults aged 18-50 years with no previous malaria vaccinations or infections, in a sequential, dose-escalating manner. Eligible participants received the monoclonal antibody CIS43LS in a single, open-label dose of 1 mg/kg, 5 mg/kg, or 10 mg/kg intravenously, or 5 mg/kg or 10 mg/kg subcutaneously. Participants underwent controlled human malaria infection by the bites of five mosquitoes infected with Plasmodium falciparum 3D7 strain approximately 8 weeks after their monoclonal antibody inoculation. Six additional control participants who did not receive CIS43LS underwent controlled human malaria infection simultaneously. Participants were followed-up daily on days 7-18 and day 21, with qualitative PCR used for P falciparum detection. Participants who tested positive for P falciparum were treated with atovaquone-proguanil and those who remained negative were treated at day 21. Participants were followed-up until 24 weeks after dosing. The primary outcome was safety and tolerability of CIS43LS at each dose level, assessed in the as-treated population. Secondary outcomes included protective efficacy of CIS43LS after controlled human malaria infection. This trial is now complete and is registered with ClinicalTrials.gov, NCT04206332. FINDINGS: Between Sept 1, 2021, and Oct 29, 2021, 47 people were assessed for eligibility and 31 were enrolled (one subsequently withdrew and was replaced) and assigned to receive doses of 1 mg/kg (n=7), 5 mg/kg (n=4), and 10 mg/kg (n=3) intravenously and 5 mg/kg (n=4) and 10 mg/kg (n=4) subcutaneously, or to the control group (n=8). CIS43LS administration was safe and well tolerated; no serious adverse events occurred. CIS43LS protected 18 (82%) of 22 participants who received a dose. No participants developed parasitaemia following dosing at 5 mg/kg intravenously or subcutaneously, or at 10 mg/kg intravenously or subcutaneously. All six control participants and four of seven participants dosed at 1 mg/kg intravenously developed parasitaemia after controlled human malaria infection. INTERPRETATION: CIS43LS was safe and well tolerated, and conferred protection against P falciparum at low doses and by the subcutaneous route, providing evidence that this approach might be useful to prevent malaria across several clinical use cases. FUNDING: National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Low-Dose Subcutaneous or Intravenous Monoclonal Antibody to Prevent Malaria.

BACKGROUND: New approaches for the prevention and elimination of malaria, a leading cause of illness and death among infants and young children globally, are needed. METHODS: We conducted a phase 1 clinical trial to assess the safety and pharmacokinetics of L9LS, a next-generation antimalarial monoclonal antibody, and its protective efficacy against controlled human malaria infection in healthy adults who had never had malaria or received a vaccine for malaria. The participants received L9LS either intravenously or subcutaneously at a dose of 1 mg, 5 mg, or 20 mg per kilogram of body weight. Within 2 to 6 weeks after the administration of L9LS, both the participants who received L9LS and the control participants underwent controlled human malaria infection in which they were exposed to mosquitoes carrying Plasmodium falciparum (3D7 strain). RESULTS: No safety concerns were identified. L9LS had an estimated half-life of 56 days, and it had dose linearity, with the highest mean (±SD) maximum serum concentration (Cmax) of 914.2±146.5 µg per milliliter observed in participants who had received 20 mg per kilogram intravenously and the lowest mean Cmax of 41.5±4.7 µg per milliliter observed in those who had received 1 mg per kilogram intravenously; the mean Cmax was 164.8±31.1 in the participants who had received 5 mg per kilogram intravenously and 68.9±22.3 in those who had received 5 mg per kilogram subcutaneously. A total of 17 L9LS recipients and 6 control participants underwent controlled human malaria infection. Of the 17 participants who received a single dose of L9LS, 15 (88%) were protected after controlled human malaria infection. Parasitemia did not develop in any of the participants who received 5 or 20 mg per kilogram of intravenous L9LS. Parasitemia developed in 1 of 5 participants who received 1 mg per kilogram intravenously, 1 of 5 participants who received 5 mg per kilogram subcutaneously, and all 6 control participants through 21 days after the controlled human malaria infection. Protection conferred by L9LS was seen at serum concentrations as low as 9.2 µg per milliliter. CONCLUSIONS: In this small trial, L9LS administered intravenously or subcutaneously protected recipients against malaria after controlled infection, without evident safety concerns. (Funded by the National Institute of Allergy and Infectious Diseases; VRC 614 ClinicalTrials.gov number, NCT05019729.).

United States regulatory requirements for skin and eye irritation testing.

PURPOSE: Eye and skin irritation test data are required or considered by chemical regulation authorities in the United States to develop product hazard labelling and/or to assess risks for exposure to skin- and eye-irritating chemicals. The combination of animal welfare concerns and interest in implementing methods with greater human relevance has led to the development of non-animal skin- and eye-irritation test methods. To identify opportunities for regulatory uses of non-animal replacements for skin and eye irritation tests, the needs and uses for these types of test data at U.S. regulatory and research agencies must first be clarified. METHODS: We surveyed regulatory and non-regulatory testing needs of U.S. Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) agencies for skin and eye irritation testing data. Information reviewed includes the type of skin and eye irritation data required by each agency and the associated decision context: hazard classification, potency classification, or risk assessment; the preferred tests; and whether alternative or non-animal tests are acceptable. Information on the specific information needed from non-animal test methods also was collected. RESULTS: A common theme across U.S. agencies is the willingness to consider non-animal or alternative test methods. Sponsors are encouraged to consult with the relevant agency in designing their testing program to discuss the use and acceptance of alternative methods for local skin and eye irritation testing. CONCLUSIONS: To advance the implementation of alternative testing methods, a dialog on the confidence of these methods to protect public health and the environment must be undertaken at all levels.

Micro-CT imaging: Developing criteria for examining fetal skeletons in regulatory developmental toxicology studies - A workshop report.

During the past two decades the use and refinements of imaging modalities have markedly increased making it possible to image embryos and fetuses used in pivotal nonclinical studies submitted to regulatory agencies. Implementing these technologies into the Good Laboratory Practice environment requires rigorous testing, validation, and documentation to ensure the reproducibility of data. A workshop on current practices and regulatory requirements was held with the goal of defining minimal criteria for the proper implementation of these technologies and subsequent submission to regulatory agencies. Micro-computed tomography (micro-CT) is especially well suited for high-throughput evaluations, and is gaining popularity to evaluate fetal skeletons to assess the potential developmental toxicity of test agents. This workshop was convened to help scientists in the developmental toxicology field understand and apply micro-CT technology to nonclinical toxicology studies and facilitate the regulatory acceptance of imaging data. Presentations and workshop discussions covered: (1) principles of micro-CT fetal imaging; (2) concordance of findings with conventional skeletal evaluations; and (3) regulatory requirements for validating the system. Establishing these requirements for micro-CT examination can provide a path forward for laboratories considering implementing this technology and provide regulatory agencies with a basis to consider the acceptability of data generated via this technology.

U.S. Food and Drug Administration approval: ofatumumab for the treatment of patients with chronic lymphocytic leukemia refractory to fludarabine and alemtuzumab.

PURPOSE: To describe the data and analyses that led to the U.S. Food and Drug Administration (FDA) approval of ofatumumab (Arzerra, GlaxoSmithKline) for the treatment of patients with chronic lymphocytic leukemia (CLL) refractory to fludarabine and alemtuzumab. EXPERIMENTAL DESIGN: The FDA reviewed the results of a planned interim analysis of a single-arm trial, enrolling 154 patients with CLL refractory to fludarabine, and a supportive dose-finding, activity-estimating trial in 33 patients with CLL. Patients in the primary efficacy study received ofatumumab weekly for eight doses, then every 4 weeks for an additional four doses; patients in the supportive trial received four weekly doses. In the primary efficacy study, endpoints were objective response rate and response duration. RESULTS: For regulatory purposes, the primary efficacy population consisted of 59 patients with CLL refractory to fludarabine and alemtuzumab. In this subgroup, the investigator-determined objective response rate was 42% [99% confidence interval (CI), 26-60], with a median duration of response of 6.5 months (95% CI, 5.8-8.3); all were partial responses. The most common adverse reactions in the primary efficacy study were neutropenia, pneumonia, pyrexia, cough, diarrhea, anemia, fatigue, dyspnea, rash, nausea, bronchitis, and upper respiratory tract infections. Infusion reactions occurred in 44% of patients with the first infusion (300 mg) and 29% with the second infusion (2,000 mg). The most common serious adverse reactions were infections, neutropenia, and pyrexia. CONCLUSIONS: On October 26, 2009, the FDA granted accelerated approval to ofatumumab for the treatment of patients with CLL refractory to fludarabine and alemtuzumab, on the basis of demonstration of durable tumor shrinkage.

Estrogen regulation of c-fos gene expression through phosphatidylinositol-3-kinase-dependent activation of serum response factor in MCF-7 breast cancer cells.

17Beta-estradiol (E2) induces proliferation and c-fos gene expression in MCF-7 cells and both responses are partially blocked by wortmannin and LY294002 which are inhibitors of phosphatidylinositol-3-kinase (PI3-K). Analysis of the c-fos gene promoter shows that the effects of wortmannin and LY294002 are associated with inhibition of E2-induced activation through the serum response factor (SRF) motif within the proximal serum response element at -325 and -296. E2 activates constructs containing multiple copies of the SRF (pSRF) and a GAL4-SRF fusion protein; these responses are accompanied by PI3-K-dependent phosphorylation of Akt and inhibited by wortmannin/LY294002, the antiestrogen ICI 182780, but not by the mitogen-activated protein kinase kinase (MAPKK) inhibitor PD98059. Using a series of kinase inhibitors and dominant negative kinase expression plasmids, it was shown that the non-genomic activation of SRF by E2 was associated with src-ras-PI3-K pathway, thus, demonstrating hormonal activation of the SRE through src-ras activation of both PI3-K- and MAPK-dependent signaling pathways.

Mechanism of action and development of selective aryl hydrocarbon receptor modulators for treatment of hormone-dependent cancers (Review).

Ligand-activated receptors are extensively used as targets for developing tissue-selective drugs for treatment of multiple diseases including cancers. The aryl hydrocarbon receptor (AhR) is a basic helix-loop-helix transcription factor that binds both synthetic chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and naturally-occurring phytochemicals, sterols and heme breakdown products. The high affinity ligand TCDD induces several AhR-mediated changes in gene expression, tissue/species-specific toxicities, and both tumorigenic and anticarcinogenic responses including inhibition of estrogen-dependent mammary and uterine tumor formation and growth. Research in this laboratory has demonstrated that TCDD inhibits E2-induced responses in the rodent uterus and mammary tumors (growth inhibition) and in breast and endometrial cancer cell lines through complex inhibitory AhR-estrogen receptor (ER) crosstalk. 6-Alkyl-1,3,8-trichlorodibenzofurans and substituted diindolylmethanes represent two structural classes of selective AhR modulators (SAhRMs). These compounds are relatively non-toxic and inhibit ER-positive and ER-negative mammary tumor growth, and synergize with tamoxifen to inhibit breast cancer growth and block tamoxifen-induced estrogenic activity in the uterus. Preliminary studies also indicate that SAhRMs inhibit prostate cancer cell growth, and there is evidence for inhibitory AhR-androgen receptor crosstalk. SAhRMs represent a novel class of drugs for treatment of hormone-dependent cancers, and combined therapies of SAhRMs with tamoxifen and other selective ER modulators (SERMs) provides a new approach for treating women with breast cancer.