ETA2023 45th Annual Meeting of the European Thyroid Association ETA 2023 Oral Session 9: Thyroid Eye Disease (5 abstracts)
1Viridian Therapeutics Inc, Nonclinical, Waltham, Massachusetts, United States; 2Viridian Therapeutics Inc, Waltham, Massachusetts, United States
Objective: Evidence shows that IGF-1 receptor (IGF-1R) antagonism reduces the inflammation and proptosis that occur in thyroid eye disease (TED). VRDN-001 is a full antagonist to IGF-1R, and VRDN-003 is a next-generation, half-life extended version of VRDN-001 designed to enable subcutaneous (SC) administration. We compared the in vivo pharmacokinetic (PK) parameters of VRDN-001 and VRDN-003 and used a PK model to simulate potential VRDN-003 SC dosing regimens.
Methods: PK parameters were assessed in cynomolgus monkeys, with a single 7.5-mg/kg dose administered via intravenous (IV) infusion or SC injection. PK samples were collected at 12 time points (VRDN-001 group) or 15 time points (VRDN-003 group); non-compartmental PK parameter estimates were calculated using Phoenix WinNonlin v8.3 PK software. A 2-compartment PK model based on VRDN-001 clinical data, with adjusted clearance to reflect the half-life extension of VRDN-003, was developed and potential clinical dose regimens were simulated.
Results: In cynomolgus monkeys, bioavailability was similar for VRDN-001 (70%) and VRDN-003 (71%). For both IV and SC administration, half-life was approximately 2 times as long for VRDN-003 vs VRDN-001, AUCinf approximately 65% greater, and clearance approximately 40% slower (Table 1). Average serum concentration of VRDN-001 administered IV Q3W was 106 μg/mL for 10 mg/kg and 32 μg/mL for 3 mg/kg. The PK model predictions for average serum concentration of VRDN-003 administered SC (300 mg in 2 mL with a 600-mg loading dose) were 104 μg/mL if given Q2W and 56 μg/mL if given Q4W.
Drug | ROA | Vza (mL/kg) | CLa(mL/day/kg) | t1/2 (days) | AUCinf (µg*day/mL) | %F |
VRDN-001 | IV | 78 ± 6 | 8.5 ± 2.1 | 6.6 ± 1.3 | 915 ± 191 | 70 |
SC | 112 ± 23 | 13.1 ± 5.6 | 6.3 ± 1.4 | 636 ± 222 | ||
VRDN-003 | IV | 86 ± 17 | 5.2 ± 0.8 | 11.9 ± 3.4 | 1480 ± 223 | 71 |
SC | 132 ± 2 | 7.2 ± 1.2 | 12.8 ± 2.0 | 1050 ± 182 | ||
aVz and CL are Vz/F and CL/F for SC routes of administration. ROA, route of administration; Vz, apparent volume of distribution of the terminal phase; CL, total clearance rate; t1/2, half-life; AUCinf, area under curve extrapolated to infinity; %F, bioavailability. |
Conclusions: VRDN-003 half-life in cynomolgus monkeys is approximately twice as long as it is for first-generation anti-IGF-1R antibodies. Based on human PK modeling, SC dosing of VRDN-003 either once or twice monthly will produce drug concentrations in the range of those achieved with Q3W IV administration of 3 mg/kg VRDN-001 and 10 mg/kg VRDN-001. These results suggest the potential for VRDN-003 efficacy via self-administered SC injection.