Transport of Designed Ankyrin Repeat Proteins through reconstituted human bronchial epithelia and protection against SARS-CoV-2.

Clinical studies have proven antiviral effectiveness of treatment with a Designed Ankyrin Repeat Protein (DARPin) specific against the spike protein of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). More information on transport mechanisms and efficiency to the site of action is desirable. Transepithelial migration through air-liquid interface (ALI) cultures of reconstituted human bronchial epithelia (HBE) was assessed by Enzyme-Linked Immunosorbent Assays and Confocal Laser Scanning Microscopy for different DARPin designs in comparison to a monoclonal antibody. Antiviral efficacy against authentic SARS-CoV-2, applied apically on HBE, was investigated based on viral titers and genome equivalents, after administration of therapeutic candidates on the basal side. Transepithelial translocation of all DARPin candidates and the monoclonal antibody was efficient and dose dependent. Small DARPins and the antibody migrated more efficiently than larger molecules, indicating different transport mechanisms involved. Microscopic analyses support this, demonstrating passive paracellular transport of smaller DARPins and transcellular migration of the larger molecules. All therapeutic candidates applied to the basal side of HBE conferred effective protection against SARS-CoV-2 infection. In summary, we have shown that DARPins specific against SARS-CoV-2 translocate across intact airway epithelia and confer effective protection against infection and viral replication.

The trispecific DARPin ensovibep inhibits diverse SARS-CoV-2 variants.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with potential resistance to existing drugs emphasizes the need for new therapeutic modalities with broad variant activity. Here we show that ensovibep, a trispecific DARPin (designed ankyrin repeat protein) clinical candidate, can engage the three units of the spike protein trimer of SARS-CoV-2 and inhibit ACE2 binding with high potency, as revealed by cryo-electron microscopy analysis. The cooperative binding together with the complementarity of the three DARPin modules enable ensovibep to inhibit frequent SARS-CoV-2 variants, including Omicron sublineages BA.1 and BA.2. In Roborovski dwarf hamsters infected with SARS-CoV-2, ensovibep reduced fatality similarly to a standard-of-care monoclonal antibody (mAb) cocktail. When used as a single agent in viral passaging experiments in vitro, ensovibep reduced the emergence of escape mutations in a similar fashion to the same mAb cocktail. These results support further clinical evaluation of ensovibep as a broad variant alternative to existing targeted therapies for Coronavirus Disease 2019 (COVID-19).

MP0250, a VEGF and HGF neutralizing DARPin® molecule shows high anti-tumor efficacy in mouse xenograft and patient-derived tumor models.

BACKGROUND: The VEGF/VEGFR and the HGF/cMET pathways are key mediators of the interplay of tumor cells and their microenvironment. However, inhibition of VEGF has been shown to produce only limited clinical benefit and inhibition of the activation of cMET by HGF has not translated into clinical benefit in pivotal trials. MP0250, a DARPin® molecule that specifically inhibits both VEGF and HGF has been developed to explore the clinical potential of dual inhibition of these pathways. RESULTS: MP0250 binding to VEGF and HGF inhibited downstream signalling through VEGFR2 and cMET resulting in inhibition of proliferation of VEGF- and HGF-dependent cells. Antitumor activity was demonstrated in VEGF- and HGF-dependent xenograft and syngeneic models with activity superior to that of individual VEGF- and HGF-blocking DARPin® molecules. Combination therapy studies showed potentiation of the antitumor activity of chemotherapy and immunotherapy agents, including an anti-PD1 antibody. MATERIALS AND METHODS: Potency of MP0250 was assessed in cellular models and in a variety of xenograft models as monotherapy or in combination with standard-of-care drugs. CONCLUSIONS: Dual inhibition of VEGF and HGF by MP0250 produced powerful single agent and combination antitumor activity. This, together with increasing understanding of the role of the HGF/cMET pathway in resistance to VEGF (and other agents), supports testing of MP0250 in the clinic.

Design and characterization of MP0250, a tri-specific anti-HGF/anti-VEGF DARPin® drug candidate.

MP0250 is a multi-domain drug candidate currently being tested in clinical trials for the treatment of cancer. It comprises one anti-vascular endothelial growth factor-A (VEGF-A), one anti-hepatocyte growth factor (HGF), and two anti-human serum albumin (HSA) DARPin® domains within a single polypeptide chain. While there is first clinical validation of a single-domain DARPin® drug candidate, little is known about DARPin® drug candidates comprising multiple domains. Here, we show that MP0250 can be expressed at 15 g/L in soluble form in E. coli high cell-density fermentation, it is stable in soluble/frozen formulation for 2 years as assessed by reverse phase HPLC, it has picomolar potency in inhibiting VEGF-A and HGF in ELISA and cellular assays, and its domains are simultaneously active as shown by surface plasmon resonance. The inclusion of HSA-binding DARPin® domains leads to a favorable pharmacokinetic profile in mouse and cynomolgus monkey, with terminal half-lives of ∼ 30 hours in mouse and ∼ 5 days in cynomolgus monkey. MP0250 is thus a highly potent drug candidate that could be particularly useful in oncology. Beyond MP0250, the properties of MP0250 indicate that multi-domain DARPin® proteins can be valuable next-generation drug candidates.