To overcome the salt-induced aggregation of CDP/pDNA nanoparticles in physiological media, chemistry was developed to conjugate a neutral stabilizing polymer, PEG, to a hydrophobic small molecule, adamantane (AD), which forms strong inclusion complexes with β-cyclodextrin. In this manner, nanoparticles could be noncovalently stabilized, and this approach was extended to allow incorporation of targeting ligands via preparation of AD-PEG-ligand conjugates

[21, 22]. Utilizing a small interfering RNA (siRNA) targeting Inhibitors,research,lifescience,medical the EWS/Fli1 fusion oncogene and the human transferrin protein as a targeting ligand, the first in vivo proof-of-concept experiments were performed shortly thereafter in a disseminated murine model of Ewing’s sarcoma [23]. The significant antitumor effect demonstrated in this work motivated the creation of a company, Inhibitors,research,lifescience,medical Calando Pharmaceuticals, to further advance this delivery platform (RONDEL) towards therapeutic candidates suitable for clinical evaluation in human cancer patients. The first such candidate, termed CALAA-01, contained an siRNA

targeting the M2 subunit of ribonucleotide reductase (RRM2), a protein involved in DNA replication whose function is required to complete cell division. Upon identification Inhibitors,research,lifescience,medical of the optimal anti-RRM2 siRNA sequence [24] and evaluation of the in vivo nanoparticle performance [25], an IND application was submitted Inhibitors,research,lifescience,medical to the Food and Drug Administration (FDA) and Calando received approval to initiate a phase I trial of CALAA-01 in patients with solid tumors in 2008. In 2010, encouraging interim clinical data from this study was published [26, 27] which revealed, in addition to a promising safety profile and multiple dose escalations, the first evidence of the RNA interference (RNAi) mechanism of action in humans and the first Inhibitors,research,lifescience,medical dose-dependent tumor accumulation in

humans of nanoparticles of any kind upon systemic administration. Figure 3 Timeline of the development of cyclodextrin-containing polymers (CDPs) for PARP inhibitor cancer nucleic acid delivery. In this paper, we describe the development of each of the components of this nucleic acid delivery system. We review the assembly of these nanoparticles, including their physicochemical Sodium butyrate properties and in vivo performance. The development of the CALAA-01 drug product is then discussed, including selection of the gene target and siRNA sequence optimization, safety and efficacy evaluations in animals, and manufacturing/scale-up of the components. The clinical findings of CALAA-01 are then discussed, including characterization of safety parameters (pharmacokinetics (PK), complement activation, cytokine levels, serum chemistry, complete blood counts (CBCs), and adverse events), and efficacy and a discussion of exploratory objectives.