Clinically relevant dosing and pharmacokinetics of DNA-encoded antibody therapeutics in a sheep model

Abstract

DNA-encoded delivery and in vivo expression of antibody therapeutics presents an innovative alternative to conventional protein production and administration, including for cancer treatment. To support clinical translation, we evaluated this approach in 18 40-45 kg sheep, using a clinical-matched intramuscular electroporation (IM EP) and hyaluronidase-plasmid DNA (pDNA) coformulation setup. Two cohorts of eight sheep received either 1 or 4 mg pDNA encoding an ovine anti-cancer embryonic antigen (CEA) monoclonal antibody (mAb; OVAC). Results showed a dose-response with average maximum serum concentrations of respectively 0.3 and 0.7 µg/ml OVAC, 4-6 weeks after IM EP. OVAC was detected in all 16 sheep throughout the 6-week follow-up, and no anti-OVAC antibodies were observed. Another, more exploratory, cohort of two sheep received a 12 mg pOVAC dose. Both animals displayed a similar dose-dependent mAb increase and expression profile in the first two weeks. However, in one animal, an anti-OVAC antibody response led to loss of mAb detection four weeks after IM EP. In the other animal, no anti-drug antibodies were observed. Serum OVAC concentrations peaked at 4.9 µg/ml 6 weeks after IM EP, after which levels gradually decreased but remained detectable around 0.2 to 0.3 µg/ml throughout a 13-month follow-up. In conclusion, using a delivery protocol that is currently employed in clinical Phase 1 studies of DNA-based antibodies, we achieved robust and prolonged in vivo production of anti-cancer DNA-encoded antibody therapeutics in sheep. The learnings from this large-animal model regarding the impact of pDNA dose and host immune response on the expressed mAb pharmacokinetics can contribute to advancing clinical translation.

Enhancing In Vivo Electroporation Efficiency through Hyaluronidase: Insights into Plasmid Distribution and Optimization Strategies

“…In our investigations encompassing both murine and rabbit models, we explored the timing of muscle pretreatment with hyaluronidase. While pDNA coformulated with hyaluronidase has been previously used in gene electrotransfer applications [ 46 , 47 , 48 ], its efficacy compared to hyaluronidase pretreatment has not been investigated. Notably, we observed no significant differences in protein production levels when pretreating the muscle with hyaluronidase either 30 min or 5 min prior to plasmid injection and electroporation.…”

Exploring the Fate of Antibody-Encoding pDNA after Intramuscular Electroporation in Mice

“…Sample collection was performed at multiple timepoints post treatment (1,4,7,14,21,42, and 84 days). At each timepoint, muscle isolation was performed for 5 mice.…”

“…This is comparable to the levels observed in sheep, where peak plasma levels reached 5 µg/mL after administration of 12 mg pOVAC in the absence of anti-drug antibodies. Sheep are more similar to humans in terms of body weight, musculature, and blood volume, and therefore these data provide valuable insights towards clinical translation [7]. For a broad implementation of DNA-based mAb delivery, a more stable expression profile at high mAb concentrations would be beneficial.…”

“…Our research group previously demonstrated proof of concept for DNA-based intramuscular gene transfer in mice, hamsters and sheep [4][5][6][7][8]. pDNA is a favorable expression platform in terms of immunogenicity, biosafety, and payload capacity compared to viral vectors.…”

Delivery platforms for broadly neutralizing antibodies

“…DMAbs hold promise to accelerate the deployment of new therapeutic interventions and provide preclinical tools for rapid evaluation of biological products. DMAbs have been tested for IgG production targeting prevention and treatment of diverse infectious diseases [15,20,22,23,25,28–36,37 ▪ ,38 ▪▪ ], and cancer [39–45] (Table 1. Current approaches for DNA delivery of antibodies).…”