Kha N. Le

Background: Class E (empty) capsid assembly modulators (CAM-Es) inhibit HBV capsid assembly, pregenomic RNA encapsidation preventing formation the establishment of covalently closed circular HBV DNA (ccDNA). ALG-000184 (pevifoscorvir sodium), is a prodrug of the Class E CAM ALG-001075. Methods: ALG-000184-201 was a Phase 1 randomized, double-blind, placebo-controlled study to evaluate the safety, tolerability and pharmacokinetics of ALG-000184. Healthy participants (n = 8/cohort) received oral single-ascending doses (SAD) of ALG-000184 (40, 100, 250, and 500 mg) or placebo, and multiple-ascending daily doses (MAD) (150 mg and 250 mg) or placebo for 7 days. Results: ALG-000184 was well tolerated by 48 participants who received single doses up to 500 mg and multiple daily doses up to 250 mg for 7 days. ALG-000184 was rapidly converted to the active moiety, ALG-001075. ALG-001075 had dose-proportional increase in plasma exposure, low-to-moderate variability (18%–34% CV for AUC _0-24 ), rapid absorption (median t _max 1–3.5 h), and biphasic distribution/elimination with terminal t½ 7–8 h and minimal accumulation (∼30%). A major oxidative metabolite, ALG-000302, was identified in plasma (∼17%–24% of ALG-001075). A high-fat/high-calorie meal did not significantly impact the plasma pharmacokinetics. No differences in pharmacokinetics between Asian and non-Asian participants were observed. A concentration QT analysis indicated no statistically significant change in ΔΔQTcF with plasma ALG-001075. Urinary excretion of ALG-001075 was low following single or multiple ALG-000184 doses. Conclusions: ALG-000184 demonstrated good tolerability, safety and pharmacokinetic properties in healthy participants. The pharmacokinetic profile suggests that a daily dose of 100 mg or higher will provide efficacious exposures in patients with chronic HBV infection. Clinical trial number: NCT04536337 ( https://clinicaltrials.gov/study/NCT04536337 ).

The SARS-CoV-2 outbreak of 2019 had a devastating impact on global health and economies worldwide. The viral cysteine protease (3CLpro) is responsible for viral polypeptide bond cleavages and is therefore an essential target to inhibit viral replication. Here, we report the discovery of an orally available, reversible covalent inhibitor of the SARS-CoV-2 main protease that is also highly active across other human coronaviruses and demonstrated oral efficacy in a Syrian hamster infection model at low plasma concentrations. Projection of pharmacokinetics (PK) in humans, based on PK studies in preclinical species and enhanced in vitro/in vivo efficacy of ALG-097558 (7) indicated the potential for BID dosing without the need for ritonavir, the PK boosting component of Paxlovid. After preclinical safety and pharmacological studies, ALG-097558 has progressed to phase 1 clinical trials.

Geographic atrophy is an advanced form of age-related macular degeneration (AMD) and a leading cause of vision loss for which there are no approved treatments. Genetic studies in AMD patients have implicated dysregulation of the alternative complement pathway in the pathogenesis of geographic atrophy. Lampalizumab is a potential therapeutic that targets complement factor D, a pivotal activator of the alternative complement pathway. The MAHALO phase 2 clinical trial was a multicenter, randomized, controlled study that evaluated lampalizumab administered by intravitreal injection monthly (n = 42) and every other month (n = 41) versus sham control (n = 40) in patients with geographic atrophy secondary to AMD. The primary endpoint was the mean change in lesion area from baseline to month 18 as measured by fundus autofluorescence. Specific AMD-associated genetic polymorphisms were also analyzed. The MAHALO study met its primary efficacy endpoint with an acceptable safety profile; monthly lampalizumab treatment demonstrated a 20% reduction in lesion area progression versus sham control [80% confidence interval (CI), 4 to 37%]. A more substantial monthly treatment benefit of 44% reduction in geographic atrophy area progression versus sham control (95% CI, 15 to 73%) was observed in a subgroup of complement factor I (CFI) risk-allele carriers (57% of the patients analyzed were CFI risk-allele carriers). The MAHALO study shows a potential treatment effect in patients with geographic atrophy and supports therapeutic targeting of the alternative complement pathway for treating AMD pathogenesis.

Anti–factor D (AFD; FCFD4514S, lampalizumab) is a humanized IgG Fab fragment directed against factor D (fD), a rate-limiting serine protease in the alternative complement pathway (AP). Evaluation of AFD as a potential intravitreal (IVT) therapeutic for dry age-related macular degeneration patients with geographic atrophy (GA) is ongoing. However, it is unclear whether IVT administration of AFD can affect systemic AP activation and potentially compromise host-immune responses. We characterized the pharmacologic properties of AFD and assessed the effects of AFD administered IVT (2 or 20 mg) or intravenous (0.2, 2, or 20 mg) on systemic complement activity in cynomolgus monkeys. For the IVT groups, serum AP activity was reduced for the 20 mg dose group between 2 and 6 hours postinjection. For the intravenous groups, AFD inhibited systemic AP activity for periods of time ranging from 5 minutes (0.2 mg group) to 3 hours (20 mg group). Interestingly, the concentrations of total serum fD increased up to 10-fold relative to predose levels following administration of AFD. Furthermore, AFD was found to inhibit systemic AP activity only when the molar concentration of AFD exceeded that of fD. This occurred in cynomolgus monkeys at serum AFD levels ≥2 µg/ml, a concentration 8-fold greater than the maximum serum concentration observed following a single 10 mg IVT dose in a clinical investigation in patients with GA. Based on these findings, the low levels of serum AFD resulting from IVT administration of a clinically relevant dose are not expected to appreciably affect systemic AP activity.

Background Data comparing systemic exposure and systemic vascular endothelial growth factor (VEGF) suppression of ranibizumab, bevacizumab and aflibercept following intravitreal injection are lacking. Methods Fifty-six patients with wet age-related macular degeneration received intravitreal ranibizumab (0.5 mg), bevacizumab (1.25 mg), or aflibercept (2.0 mg). Serum pharmacokinetics and plasma free VEGF were evaluated after the first and third injections. Results Following the first dose, systemic exposure to aflibercept was 5-, 37-, and 9-fold higher than ranibizumab, whereas, bevacizumab was 9-, 310-, and 35-fold higher than ranibizumab, based on geometric mean ratio of peak and trough concentrations and area under the curve, respectively. The third dose showed accumulation of bevacizumab and aflibercept but not ranibizumab. Aflibercept substantially suppressed plasma free VEGF, with mean levels below lower limit of quantitation (10 pg/mL) as early as 3 h postdose until ≥7 days postdose. Mean free (unbound) VEGF levels with ranibizumab were largely unchanged, with mean trough level of 14.4 pg/mL compared with baseline of 17 pg/mL. Conclusions There are notable differences in systemic pharmacokinetics and pharmacodynamics among anti-VEGF treatments after intravitreal administration. All three agents rapidly moved into the bloodstream, but ranibizumab very quickly cleared, whereas bevacizumab and aflibercept demonstrated greater systemic exposure and produced a marked reduction in plasma free VEGF. Trial registration number NCT02118831.

Background— The challenge of angiogenesis science is that stable sustained vascular regeneration in humans has not been realized despite promising preclinical findings. We hypothesized that angiogenic therapies powerfully self-regulate by dynamically altering tissue characteristics. Induced neocapillaries increase drug clearance and limit tissue retention and subsequent angiogenesis even in the face of sustained delivery. Methods and Results— We quantified how capillary flow clears fibroblast growth factor after local epicardial delivery. Fibroblast growth factor spatial loading was significantly reduced with intact coronary perfusion. Penetration and retention decreased with transendothelial permeability, a trend diametrically opposite to intravascular delivery, in which factor delivery depends on vascular leak, but consistent with a continuum model of drug transport in perfused tissues. Model predictions of fibroblast growth factor sensitivity to manipulations of its diffusivity and transendothelial permeability were validated by conjugation to sucrose octasulfate. Induction of neocapillaries adds pharmacokinetic complexity. Sustained local fibroblast growth factor delivery in vivo produced a burst of neovascularization in ischemic myocardium but was followed by drug washout and a 5-fold decrease in fibroblast growth factor penetration depth. Conclusions— The very efficacy of proangiogenic compounds enhances their clearance and abrogates their pharmacological benefit. This self-limiting property of angiogenesis may explain the failures of promising proangiogenic therapies.