Human Genome Sciences

Measurement and characterization of subvisible particles (including proteinaceous and non-proteinaceous particulate matter) is an important aspect of the pharmaceutical development process for biotherapeutics. Health authorities have increased expectations for subvisible particle data beyond criteria specified in the pharmacopeia and covering a wider size range. In addition, subvisible particle data is being requested for samples exposed to various stress conditions and to support process/product changes. Consequently, subvisible particle analysis has expanded beyond routine testing of finished dosage forms using traditional compendial methods. Over the past decade, advances have been made in the detection and understanding of subvisible particle formation. This article presents industry case studies to illustrate the implementation of strategies for subvisible particle analysis as a characterization tool to assess the nature of the particulate matter and applications in drug product development, stability studies and post-marketing changes.

Measurement and characterization of subvisible particles (defined here as those ranging in size from 2 to 100μm), including proteinaceous and nonproteinaceous particles, is an important part of every stage of protein therapeutic development. The tools used and the ways in which the information generated is applied depends on the particular product development stage, the amount of material, and the time available for the analysis. In order to compare results across laboratories and products, it is important to harmonize nomenclature, experimental protocols, data analysis, and interpretation. In this manuscript on perspectives on subvisible particles in protein therapeutic drug products, we focus on the tools available for detection, characterization, and quantification of these species and the strategy around their application.

Although antibiotics treat bacteremia in inhalational anthrax, pathogenesis is mainly driven by bacterial exotoxins. Raxibacumab, an IgG1 monoclonal antibody, binds the protective antigen (PA) of Bacillus anthracis, thus blocking toxin effects and leading to improved survival in the rabbit and monkey models of inhalational anthrax. To assess raxibacumab's added benefit over levofloxacin (LVX) alone, rabbits surviving to 84 h after a challenge with 200 times the median (50%) lethal dose of B. anthracis spores were randomized to receive 3 daily intragastric LVX doses of 50 mg/kg of body weight, with the first LVX dose administered just prior to administration of a single intravenous dose of placebo or 40 mg/kg raxibacumab. The percentages of animals alive at 28 days following the last LVX dose were compared between the 2 treatment groups using a two-sided likelihood- ratio chi-square test. The 82% survival rate for the LVX-raxibacumab combination was higher than the 65% survival rate for LVX alone (P = 0.0874). There were nearly 2-fold fewer deaths for the combination (7 deaths; n = 39) than for LVX alone (13 deaths; n = 37), and the survival time was prolonged for the combination (P = 0.1016). Toxin-neutralizing-activity titers were similar for both treatment groups, suggesting that survivors in both groups were able to mount a toxin-neutralizing immune response. Microscopic findings considered consistent with anthrax were present in animals that died or became moribund on study in both treatment groups, and there were no anthrax-related findings in animals that survived. Overall, raxibacumab provided a meaningful benefit over antibiotic alone when administered late in the disease course.

3024 Background: MEDI0639 is an investigational monoclonal antibody that selectively binds to Delta-like ligand 4 (DLL4) and blocks its ability to bind to and activate signaling through the Notch receptors, potentially inhibiting tumor growth by multiple mechanisms. Methods: This study (NCT01577745) included patients (pts) with advanced solid tumors who had ECOG performance status 0–1 and adequate organ function. MEDI0639 10–200 mg was given every 21 days with a 3+3 dose-escalation design. Primary objective was to determine maximum tolerated dose (MTD) and safety. Other objectives included pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity (IG), and antitumor activity. Results: As of Jan 7, 2015, 20 pts were enrolled (median age 61y [range 40–83y]; median number of prior therapies: 5). The most common tumors were colorectal (n = 5), small cell lung cancer (n = 4), and melanoma (n = 4). No dose-limiting toxicities were identified through the 150 mg dose; the 200 mg dose is currently being evaluated. Of 20 safety-evaluable pts, the most common treatment-related adverse events (trAEs) were increased aspartate aminotransferase, increased brain natriuretic peptide (BNP), and fatigue (n = 3 each). Grade 3/4 trAEs were observed in 3 pts (acute myocardial infarction [AMI], atrial fibrillation [AF], ventricular dilatation [VD], and ventricular hypokinesia [VH] in 1 pt; lower abdominal pain in 1 pt, and hypertension in 1 pt), and 3 pts had serious trAEs (AMI, AF, VD, VH in 1 pt; diplopia in 1 pt; hemorrhagic diarrhea (HD), chest discomfort, and back pain in 1 pt). One pt discontinued due to a trAE (AMI). The trAEs of interest consistent with the mechanism of action included AMI (n = 1), hypertension (n = 2), increased BNP (n = 3), and HD (n = 1). No treatment-related deaths occurred. Of 19 efficacy evaluable pts, partial response was observed in 1 pt with melanoma; 7 pts had stable disease lasting ≥ 12 weeks. Preliminary PK was nonlinear at doses < 100 mg, and PD showed target engagement at the doses tested. IG has not been observed. Conclusions: MEDI0639 150 mg did not exceed the MTD. Enrollment at the 200 mg dose level is ongoing. The safety profile is consistent with the mechanism of action and appears to be manageable. Preliminary evidence of antitumor activity was observed. Clinical trial information: NCT01577745.

There is increasing evidence that some cancer therapies can promote tumor immunogenicity to boost the endogenous antitumor immune response. In this study, we used the novel combination of agonistic anti-TRAIL-R1 antibody (mapatumumab, Mapa) with low dose bortezomib (LDB) for this purpose. The combination induced profound myeloma cell apoptosis, greatly enhanced the uptake of myeloma cell apoptotic bodies by dendritic cell (DC) and induced anti-myeloma cytotoxicity by both CD8+ T cells and NK cells. Cytotoxic lymphocyte expansion was detected within 24 h of commencing therapy and was maximized when myeloma-pulsed DC were co-treated with low dose bortezomib and mapatumumab (LDB+Mapa) in the presence of NK cells. This study shows that Mapa has two distinct but connected modes of action against multiple myeloma (MM). First, when combined with LDB, Mapa produced powerful myeloma cell apoptosis; secondly, it promoted DC priming and an NK cell-mediated expansion of anti-myeloma cytotoxic lymphocyte (CTL). Overall, this study indicates that Mapa can be used to drive potent anti-MM immune responses.