Anrukinzumab

Asthma is a complex, heterogeneous, airway inflammatory disorder broadly classified into atopic (IgE mediated) and non-atopic asthma. Monoclonal Antibodies (MAbs) and small chemical Protein- Protein Interaction Modulators (PPIMs) are targeted against interleukins (ILs), which play a critical role in asthma. Many MAbs are targeted against ILs and IgE. Anti IgE MAb (Omalizumab) and Anti IL- 5 MAbs (Mepolizumab, Reslizumab) have only been approved by FDA. Most of the MAbs including Tracolizumab, Lebrikizumab, Anrukinzumab (Anti IL-13 MAb), and Brodalumab (Anti IL-17 MAb) are in different phases of clinical trials. Pascolizumab (Anti IL-4 MAb), however, has failed. These MAbs are expensive and may render adverse immune response. Thus, small chemical modulators targeting ILs and their receptors (IL-Rs) are being exploited computationally and further validated experimentally. The complex ILs and IL-Rs available in PDB are best suited for these types of studies. A large number of small chemical modulators against Protein-Protein Interactions (PPIs) have been compiled in a few databases like TIMBAL, 2P2I DB and IPPIDB. Small chemical libraries are used for virtual screening to find novel modulators targeting IL-R binding interface on IL. Molecular dynamic simulations have been further used for disruption mechanism and kinetic studies. IL-2/IL-2R was targeted with clinically tested small molecule modulators like SP4206, and IL-2 levels were known to increase in non-atopic asthma. In the absence of experimentally known modulators against atopic asthma, computational tools are being explored. For example, IL-33 is a target for atopic asthma where IL-33 and its receptor complex structure is available in PDB. In summary, small chemical modulators against ILs are a complementary approach to MAbs and computational tools have been used for identifying these modulators for asthma.

IMA-638 and IMA-026 are humanized IgG1 monoclonal antibodies (mAbs) that target non-overlapping epitopes of IL-13. Separate first-in-human single ascending dose studies were conducted for each mAb. These studies had similar study designs, but mild to moderate asthmatics were recruited for the IMA-638 study and healthy subjects were recruited for the IMA-026 study. IMA-638 and IMA-026 showed similar pharmacokinetic (PK) profiles, but very different total IL-13 (free and drug bound IL-13) profiles; free IL13 was not measured. IMA-026 treatment induced a dose-dependent accumulation of total IL-13, while IMA-638 treatment led to a much smaller accumulation without any clear dose-response. To understand the differences between the two total IL-13 profiles and to predict the free IL-13 profiles for each mAb treatment, a mechanistic PK/pharmacodynamic model was developed. PK-related parameters were first fit to the mean PK profiles of each mAb separately; thereafter, the target-related parameters were fit to both total IL-13 profiles simultaneously. The IL-13 degradation rate was assumed to be the same for asthma patients and healthy subjects. The model suggests that an approximately 100× faster elimination of IL-13-IMA-638 complex than IL-13-IMA-026 complex could be responsible for the differences observed in total IL-13 profiles for the two mAbs. Furthermore, the model predicts that IMA-638 administration results in greater and more prolonged free IL-13 inhibition than equivalent dosing of IMA-026 despite similar binding KD and PK profile. In conclusion, joint modeling of two similar molecules provided mechanistic insight that the elimination rate of mAb-target complex can regulate the degree of free target inhibition.