Safety, Pharmacokinetics, Serum Neutralizing Titers, and Immunogenicity of Adintrevimab, a Monoclonal Antibody Targeting SARS-CoV-2: A Randomized, Double-Blind, Placebo-Controlled, Phase 1 Dose-escalation Study in Healthy Adults

INTRODUCTION

Adintrevimab is a fully human immunoglobulin G1 extended half-life monoclonal antibody that was developed to have broad neutralization against SARS-CoV, SARS-CoV-2, and other SARS-like CoVs with pandemic potential. Here we report the safety, pharmacokinetics (PK), serum viral neutralizing antibody (sVNA) titers, and immunogenicity results of the first three cohorts evaluated in the first-in-human study of adintrevimab in healthy adults.

METHODS

This is a phase 1, randomized, placebo-controlled, single ascending-dose study of adintrevimab administered intramuscularly (IM) or intravenously (IV) to healthy adults aged ≥ 18-55 years with no current or prior SARS-CoV-2 infection. Participants were randomized 8:2 to adintrevimab or placebo in each of three dose cohorts: adintrevimab 300 mg IM (cohort 1), 500 mg IV (cohort 2), and 600 mg IM (cohort 3). Follow-up was 12 months. Blood samples were taken predose and at multiple time points postdose up to month 12 to assess sVNA, PK, and antidrug antibodies (ADAs).

RESULTS

Thirty participants received a single dose of adintrevimab (n = 24; 8 per cohort) or placebo (n = 6). All except one adintrevimab participant in cohort 1 completed the study. No participants in any treatment arm experienced a study drug-related adverse event. Across adintrevimab-treated participants, 11 (45.8%) experienced at least one TEAE. All but one TEAE were mild in severity, and all were either viral infection or respiratory symptoms. There were no serious adverse events, discontinuations due to adverse events, or deaths. Adintrevimab exhibited a linear and dose-proportional PK profile and extended serum half-life (mean 96, 89, and 100 days in cohorts 1, 2, and 3, respectively). Participants receiving adintrevimab demonstrated dose-dependent increased sVNA titers and breadth across multiple variants.

CONCLUSION

Adintrevimab at doses of 300 mg IM, 500 mg IV, and 600 mg IM was well tolerated in healthy adults. Adintrevimab demonstrated dose-proportional exposure, rapid development of neutralizing antibody titers, and an extended half-life.

226. Higher Doses of Adintrevimab, an Extended Half-Life Monoclonal Antibody, for the Treatment and Prevention of COVID-19: Preliminary Results from a Phase 1 Single Ascending-Dose Study

Background

Adintrevimab is a fully human IgG1 monoclonal antibody engineered to have potent and broad neutralization against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other SARS-like CoVs with pandemic potential. Adintrevimab is being assessed in two separate phase 2/3 clinical trials: the EVADE trial for prevention of COVID-19 in both post-exposure and pre-exposure settings and the STAMP trial for treatment of COVID-19. Here we report higher doses being evaluated in a healthy volunteer study given that emerging variants may have varying susceptibilities to adintrevimab. Previous results 300 mg IM, 600 mg IM, and 500 mg IV cohorts have been reported.

Methods

This is an ongoing Phase 1, randomized, placebo (PBO)-controlled, single ascending-dose study of adintrevimab administered intramuscularly (IM) or intravenously (IV) to healthy adults aged 18–50 years with no current SARS-CoV-2 infection. Participants were randomized 8:2 in 3 high dose cohorts (N=10/cohort: n=8 adintrevimab, n=2 PBO): adintrevimab 1200 mg IM, 1200 mg IV, and 4500 mg IV. Safety, tolerability, and pharmacokinetics (PK) were assessed up to 21 days post dose.

Results

Overall, 30 participants received adintrevimab (n=24) or PBO (n=6). Blinded safety data for all cohorts and PK for 1200 mg IV are reported. Through 21 days post dose all doses were well-tolerated, with no study drug-related adverse events (AEs), serious AEs, injection site reactions, or hypersensitivity reactions reported. The observed PK profile of the 1200 mg IV dose included Cmax of 423±105 µg/ml. Comparison of 500 mg and 1200 mg IV doses indicate dose proportionality of Cmax and exposure (AUC Day 21).

Conclusion

A single dose of adintrevimab, up to 4500 mg, was well tolerated. These preliminary safety data and PK support potential use of higher doses of adintrevimab as needed to address emerging SARS-CoV-2 variants.

Disclosures

Xia Pu, PhD, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Jean Gong, PhD, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Ed Campanaro, BSN, MSHS, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Kristin Narayan, PhD, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Deepali Gupta, B.Sc, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Frank Engler, PhD, Adagio Therapeutics: Advisor/Consultant Amanda Copans, PharmD, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds Pete Schmidt, MD, Adagio Therapeutics: Employee|Adagio Therapeutics: Stocks/Bonds.

Ledipasvir/sofosbuvir for treatment of hepatitis C virus in sofosbuvir-experienced, NS5A treatment-naïve patients: Findings from two randomized trials

BACKGROUND & AIMS

We report data from two similarly designed studies that evaluated the efficacy, safety, and optimal duration of ledipasvir/sofosbuvir (LDV/SOF) ± ribavirin (RBV) for retreatment of chronic hepatitis C virus (HCV) in individuals who failed to achieve sustained virological response (SVR) with prior SOF-based, non-NS5A inhibitor-containing regimens.

METHODS

The RESCUE study enrolled HCV mono-infected adults with genotype (GT) 1 or 4. Non-cirrhotic participants were randomized to 12 weeks of LDV/SOF or LDV/SOF + RBV. Compensated cirrhotic participants were randomized to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). The AIDS Clinical Trials Group A5348 study randomized genotype 1 adults with HCV/HIV co-infection to LDV/SOF + RBV (12 weeks) or LDV/SOF (24 weeks). Both studies used SVR at 12 weeks post-treatment (SVR12) as the primary endpoint.

RESULTS

In the RESCUE study, 82 participants were randomized and treated, and all completed treatment. Overall, SVR12 was 88% (72/82); 81-100% in non-cirrhotic participants treated with LDV/SOF or LDV/SOF + RBV for 12 weeks and 80-92% in cirrhotic participants treated with LDV/SOF + RBV for 12 weeks or LDV/SOF for 24 weeks. Adverse events (AEs), mostly mild-to-moderate in severity, were experienced by 78% of participants, with headache and fatigue most frequently reported. One serious AE, not related to treatment, was observed. No premature discontinuations of study drug, or deaths occurred. In the A5348 study, seven participants were randomized (cirrhotic n = 1; GT1a n = 5) and all attained SVR12, with no serious AEs or premature discontinuations.

CONCLUSIONS

In this SOF-experienced, NS5A inhibitor-naïve population, which included participants with cirrhosis or HCV/HIV co-infection, high SVR12 rates were achieved.

Efficacy of Sofosbuvir Plus Ribavirin in Veterans With Hepatitis C Virus Genotype 2 Infection, Compensated Cirrhosis, and Multiple Comorbidities

BACKGROUND & AIMS

We conducted a phase 4, open-label study with limited exclusion criteria to evaluate the safety and efficacy of sofosbuvir and ribavirin in veterans with hepatitis C virus genotype 2 infection, and compensated cirrhosis. This population is often excluded from clinical studies.

METHODS

We performed a prospective study of treatment-naive (n = 47) and treatment-experienced (n = 19) patients with chronic hepatitis C virus genotype 2 infection and compensated cirrhosis at 15 Department of Veterans Affairs sites. All subjects were given sofosbuvir (400 mg, once daily) plus ribavirin (1000-1200 mg/day) in divided doses for 12 weeks. Patients with major psychiatric diseases or alcohol or substance use disorders were not excluded. The primary endpoint was sustained virologic response 12 weeks after therapy.

RESULTS

Fifty-two patients achieved a sustained virologic response 12 weeks after therapy (79%; 95% confidence interval, 67%-88%); 16 of these patients were treatment experienced (84%; 95% confidence interval, 60%-97%) and 36 were treatment naive (77%; 95% confidence interval, 62%-88%). All patients had at least 1 comorbidity. Thirty-five percent had depression, 24% had posttraumatic stress disorder, and 30% had anxiety disorder. In addition, 29% had current substance use. Of the 7 patients (11%) who discontinued the study treatment prematurely, 3 did so because of adverse events. The most common adverse events were fatigue, anemia, nausea, and headache. Serious adverse events occurred in 8 patients. Only 2 of the serious adverse events (anemia and nausea) were considered to be related to study treatment.

CONCLUSIONS

In a phase 4 study, 12 weeks treatment with sofosbuvir and ribavirin led to a sustained virologic response 12 weeks after therapy in almost 80% of veterans with hepatitis C virus genotype 2 infection, compensated cirrhosis, and multiple comorbidities, regardless of their treatment history. ClinicalTrials.gov, Number: NCT02128542.