Development of a hyperimmune equine serum therapy for COVID-19 in Argentina.

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab')2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab')2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Physicochemical and Biological Characterization of RTXM83, a New Rituximab Biosimilar.

BACKGROUND: RTXM83 is a rituximab biosimilar with proven clinical safety and efficacy. It is the first rituximab biosimilar developed and approved in South America and is currently marketed in several Latin American, Middle Eastern and African countries. OBJECTIVE: The aim of this study was to present the physicochemical and biological characterization studies utilized to demonstrate the similarity between RTXM83 and its reference product. METHODS: Primary and higher order protein structures were analysed using peptide mapping with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), fluorescence spectroscopy and circular dichroism, and micro-differential scanning calorimetry, among other techniques. Charge variants were determined by cation-exchange chromatography (CEX) and capillary isoelectric focusing (cIEF). Glycosylation and glycoforms distribution were analysed using MS, normal phase high-performance liquid chromatography (NP-HPLC) and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD). Size variants were evaluated by size-exclusion chromatography (SEC), sedimentation velocity analytical ultracentrifugation (SV-AUC), dynamic light scattering (DLS), and capillary electrophoresis-sodium dodecyl sulfate (CE-SDS). Biological characterization included binding assays for complement C1q, CD20, and several Fc receptors (FcRs), as well as potency determination for in vitro apoptosis induction, complement-dependent cytotoxicity (CDC), and antibody-dependent cell-mediated cytotoxicity (ADCC). RESULTS: RTXM83 and the reference product showed identical primary sequences and disulfide bridge patterns, and similarity at higher order protein structures, post-translational modification profiles (amino acid modifications, charge variants, and glycosylation) and levels of purity and process-related impurities. Functional studies demonstrated that RTXM83 is similar to the reference product regarding the three known mechanisms of action of rituximab: CDC, ADCC, and apoptosis induction. Binding affinities to CD20, complement component C1q, and different FcRs were also equivalent. CONCLUSION: RTXM83 is similar to its reference product in all critical quality attributes.

UV-specific DNA repair recombinant fusion enzyme: a new stable pharmacologically active principle suitable for photoprotection.

BACKGROUND: UV radiation can produce mutations in skin cells and correlates strongly with the onset of actinic keratoses and basal and squamous cell carcinomas. Xeroderma pigmentosum (XP) is a heritable disease characterized by an extreme sensitivity of skin to UV radiation. Recently, studies in cultured cells as well as in XP patients have demonstrated that the recombinant T4 endonuclease V UV-specific endonuclease could enhance repair of UV-induced photoproducts. OBJECTIVE: We aimed to obtain a stable UV-specific DNA recombinant endonuclease, pharmacologically active in mammalian cells so as to be used in treatment and prophylaxis of sun damage. METHODS: The UV-specific DNA endonuclease gene obtained from Micrococcus luteus, was fused to a leader peptide and expressed (alphaUveA), refolded and purified. A construction under the control of an eukaryotic promoter was used to transfect XP fibroblasts deficient in DNA damage repair. Transformed cells were UV irradiated and cell survival was assessed. RESULTS: alphaUveA was obtained as a highly active UV-specific repair enzyme stable for at least 2 years. XP fibroblasts transfected with alphaUveA gene increased the resistance to UV radiation and, in consequence, cell survival. CONCLUSION: alphaUveA is stable and pharmacologically active in human cells. The topical administration of this long-term stable new active principle could help diminish the risks of skin cancer after sun exposure.

Development of a hyperimmune equine serum therapy for COVID-19 in Argentina

The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab’)2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina.

La enfermedad denominada COVID-19 es causada por el coronavirus SARS-CoV-2 y es actualmente considerada una pandemia a nivel global. El desarrollo de vacunas es sin duda la mejor estrategia a largo plazo, pero debido a la emergencia sanitaria, existe una necesidad urgente de encontrar soluciones rápidas y efectivas para el tratamiento de la enfermedad. Hasta la fecha, el uso de plasma de convalecientes es la única inmunoterapia disponible para pacientes hospitalizados con COVID-19. El uso de anticuerpos policlonales equinos (EpAbs) es otra alternativa terapéutica interesante. La nueva generación de EpAbs incluyen el procesamiento y purificación de los mismos y la obtención de fragmentos F(ab’)2 con alta pureza y un excelente perfil de seguridad en humanos. Los EpAbs son fáciles de producir, lo cual permite el desarrollo rápido y la elaboración a gran escala de un producto terapéutico. En este trabajo mostramos el desarrollo de un suero terapéutico obtenido luego de la inmunización de caballos utilizando el receptor-binding domain de la glicoproteína Spike del virus. Nuestro producto mostró ser alrededor de 50 veces más potente en ensayos de seroneutralización in vitro que el promedio de los plasmas de convalecientes. Estos resultados nos permitirían testear la seguridad y eficacia de nuestro producto en ensayos clínicos de fase 2/3 a realizarse a partir de julio de 2020 en la zona metropolitana de Buenos Aires, Argentina.

Immunogenicity and reactogenicity of a combined fully liquid DTPw-HepB-Hib pentavalent vaccine in healthy infants: no clinically relevant impact of a birth dose of hepatitis B vaccine.

OBJECTIVES: In this open-label, non-randomized phase II study, the safety and immunogenicity of a fully liquid diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HepB-Hib) combination vaccine (Quinvaxem(®)) were assessed in infants who had or had not received a birth dose of hepatitis B (HepB) vaccine. STUDY DESIGN: Two groups of infants, 'HepB at birth' (n=110) and 'no HepB at birth' (n=108), were enrolled and received a primary vaccination course using a 2-4-6 months schedule. RESULTS: Seroprotection/seroconversion rates of >95% were achieved against all antigens included in the combination vaccine for both study groups. Although significantly higher anti-hepatitis B virus (p<0.001) and anti-tetanus (p=0.031) antibody titers were achieved in group 'HepB at birth' when compared with group 'no HepB at birth', the proportion of 'no HepB at birth' subjects achieving protective titers was non-inferior to the proportion of subjects in group 'HepB at birth'. The birth dose of HepB vaccine did not seem to influence the safety pattern of the DTPw-HepB-Hib combination vaccine. CONCLUSIONS: The present study demonstrated that the fully liquid DTPw-HepB-Hib vaccine was safe and immunogenic when administered using a 2-4-6 months immunization schedule, regardless of whether or not infants had received a dose of HepB vaccine at birth.

A controlled clinical trial comparing the safety and immunogenicity of a new adjuvanted hepatitis B vaccine with a standard hepatitis B vaccine.

A randomised trial was conducted in 285 adults not immune to hepatitis B (HB) to compare the safety and immunogenicity of a commercial aluminium-adjuvanted HB vaccine with and without an additional new adjuvant (AgB/RC-210-04 or AgB study groups, respectively). The additional adjuvant RC-529 is a fully synthetic monosaccharide mimetic of monophosphoryl lipid A. Subjects in the AgB/RC-210-04 (n=136) and AgB (n=149) groups were vaccinated intramuscularly on days 0, 30, and 180, according to the standard vaccination schedule for hepatitis B vaccines. Serum levels of anti-HBs were measured on days 30, 60, 90, 180, and 210. Standard safety assessments were made throughout the study period. The rates of seroprotection (anti-HBs > or =10.0 mIU/ml) were significantly greater for the AgB/RC-210-04 group at all time points: at day 90, the seroprotection rate, the primary endpoint of the trial, was 99% for AgB/RC-210-04 compared with 84% for AgB (p<0.0001). Similarly, geometric mean anti-HBs titres were significantly higher at all time points for the AgB/RC-210-04 group. There were more local reactions in the AgB/RC-210-04 group, however they were transient and this double-adjuvanted formulation was well tolerated. We conclude that the addition of a synthetic adjuvant to the AgB vaccine significantly enhanced the immunogenicity of the commercial vaccine AgB. The results indicate furthermore that a two-dose regime of the double-adjuvanted vaccine (schedule: 0-1 month) may be sufficient to achieve seroprotection in nearly 100% of individuals.