A randomized, controlled Phase 1b trial of the Sm-TSP-2 Vaccine for intestinal schistosomiasis in healthy Brazilian adults living in an endemic area.

BACKGROUND: Recombinant Schistosoma mansoni Tetraspanin-2 formulated on Alhydrogel (Sm-TSP-2/Alhydrogel) is being developed to prevent intestinal and hepatic disease caused by S. mansoni. The tegumentary Sm-TSP-2 antigen was selected based on its unique recognition by cytophilic antibodies in putatively immune individuals living in areas of ongoing S. mansoni transmission in Brazil, and preclinical studies in which vaccination with Sm-TSP-2 protected mice following infection challenge. METHODS: A randomized, observer-blind, controlled, Phase 1b clinical trial was conducted in 60 healthy adults living in a region of Brazil with ongoing S. mansoni transmission. In each cohort of 20 participants, 16 were randomized to receive one of two formulations of Sm-TSP-2 vaccine (adjuvanted with Alhydrogel only, or with Alhydrogel plus the Toll-like receptor-4 agonist, AP 10-701), and 4 to receive Euvax B hepatitis B vaccine. Successively higher doses of antigen (10 µg, 30 µg, and 100 µg) were administered in a dose-escalation fashion, with progression to the next dose cohort being dependent upon evaluation of 7-day safety data after all participants in the preceding cohort had received their first dose of vaccine. Each participant received 3 intramuscular injections of study product at intervals of 2 months and was followed for 12 months after the third vaccination. IgG and IgG subclass antibody responses to Sm-TSP-2 were measured by qualified indirect ELISAs at pre- and post-vaccination time points through the final study visit. RESULTS: Sm-TSP-2/Alhydrogel administered with or without AP 10-701 was well-tolerated in this population. The most common solicited adverse events were mild injection site tenderness and pain, and mild headache. No vaccine-related serious adverse events or adverse events of special interest were observed. Groups administered Sm-TSP-2/Alhydrogel with AP 10-701 had higher post-vaccination levels of antigen-specific IgG antibody. A significant dose-response relationship was seen in those administered Sm-TSP-2/Alhydrogel with AP 10-701. Peak anti-Sm-TSP-2 IgG levels were observed approximately 2 weeks following the third dose, regardless of Sm-TSP-2 formulation. IgG levels fell to low levels by Day 478 in all groups except the 100 µg with AP 10-701 group, in which 57% of subjects (4 of 7) still had IgG levels that were ≥4-fold higher than baseline. IgG subclass levels mirrored those of total IgG, with IgG1 being the predominant subclass response. CONCLUSIONS: Vaccination of adults with Sm-TSP-2/Alhydrogel in an area of ongoing S. mansoni transmission was safe, minimally reactogenic, and elicited significant IgG and IgG subclass responses against the vaccine antigen. These promising results have led to initiation of a Phase 2 clinical trial of this vaccine in an endemic region of Uganda. TRIAL REGISTRATION: NCT03110757.

The Abbott Pandemic Defense Coalition: a unique multisector approach adds to global pandemic preparedness efforts.

Detection and epidemiologic characterization of infectious disease outbreaks are key for early identification and response to potential pandemic threats. The rapid global spread of severe SARS-CoV-2 in 2020 highlighted the critical role of diagnostics in understanding the epidemiology of the virus early in the pandemic. As a natural extension of Abbott's work in diagnostics, virus discovery, and virus surveillance, the Abbott Pandemic Defense Coalition (APDC) was launched in early 2021. The APDC is a global multisector scientific and public health partnership whose primary objective is the early detection and mitigation of infectious disease threats of pandemic potential. As of January 2022, the APDC network has partners on 5 continents including academic institutions, governmental, and nongovernmental organizations. A novel element of the APDC is the capacity for early development and rapid deployment of scalable, quality diagnostics targeting newly identified pathogens of pandemic potential.