9 research outputs found
Computationally Designed Bispecific Antibodies using Negative State Repertoires
A challenge in the structure-based design of specificity is modeling the negative states, i.e., the complexes that you do not want to form. This is a difficult problem because mutations predicted to destabilize the negative state might be accommodated by small conformational rearrangements. To overcome this challenge, we employ an iterative strategy that cycles between sequence design and protein docking in order to build up an ensemble of alternative negative state conformations for use in specificity prediction. We have applied our technique to the design of heterodimeric CH3 interfaces in the Fc region of antibodies. Combining computationally and rationally designed mutations produced unique designs with heterodimer purities greater than 90%. Asymmetric Fc crystallization was able to resolve the interface mutations; the heterodimer structures confirmed that the interfaces formed as designed. With these CH3 mutations, and those made at the heavy-/light-chain interface, we demonstrate one-step synthesis of four fully IgG-bispecific antibodies
Durvalumab Plus Carboplatin/Paclitaxel Followed by Maintenance Durvalumab With or Without Olaparib as First-Line Treatment for Advanced Endometrial Cancer: The Phase III DUO-E Trial
PURPOSE Immunotherapy and chemotherapy combinations have shown activity in endometrial cancer, with greater benefit in mismatch repair (MMR)-deficient (dMMR) than MMR-proficient (pMMR) disease. Adding a poly(ADP-ribose) polymerase inhibitor may improve outcomes, especially in pMMR disease. METHODS This phase III, global, double-blind, placebo-controlled trial randomly assigned eligible patients with newly diagnosed advanced or recurrent endometrial cancer 1:1:1 to: carboplatin/paclitaxel plus durvalumab placebo followed by placebo maintenance (control arm); carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib placebo (durvalumab arm); or carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib (durvalumab + olaparib arm). The primary end points were progression-free survival (PFS) in the durvalumab arm versus control and the durvalumab + olaparib arm versus control. RESULTS Seven hundred eighteen patients were randomly assigned. In the intention-to-treat population, statistically significant PFS benefit was observed in the durvalumab (hazard ratio [HR], 0.71 [95% CI, 0.57 to 0.89]; P = .003) and durvalumab + olaparib arms (HR, 0.55 [95% CI, 0.43 to 0.69]; P < .0001) versus control. Prespecified, exploratory subgroup analyses showed PFS benefit in dMMR (HR [durvalumab v control], 0.42 [95% CI, 0.22 to 0.80]; HR [durvalumab + olaparib v control], 0.41 [95% CI, 0.21 to 0.75]) and pMMR subgroups (HR [durvalumab v control], 0.77 [95% CI, 0.60 to 0.97]; HR [durvalumab + olaparib v control] 0.57; [95% CI, 0.44 to 0.73]); and in PD-L1-positive subgroups (HR [durvalumab v control], 0.63 [95% CI, 0.48 to 0.83]; HR [durvalumab + olaparib v control], 0.42 [95% CI, 0.31 to 0.57]). Interim overall survival results (maturity approximately 28%) were supportive of the primary outcomes (durvalumab v control: HR, 0.77 [95% CI, 0.56 to 1.07]; P = .120; durvalumab + olaparib v control: HR, 0.59 [95% CI, 0.42 to 0.83]; P = .003). The safety profiles of the experimental arms were generally consistent with individual agents. CONCLUSION Carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab with or without olaparib demonstrated a statistically significant and clinically meaningful PFS benefit in patients with advanced or recurrent endometrial cancer
Rapid and robust antibody Fab fragment crystallization utilizing edge-to-edge beta-sheet packing.
Antibody therapeutics are one of the most important classes of drugs. Antibody structures have become an integral part of predicting the behavior of potential therapeutics, either directly or as the basis of modeling. Structures of Fab:antigen complexes have even greater value. While the crystallization and structure determination of Fabs is easy relative to many other protein classes, especially membrane proteins, broad screening and optimization of crystalline hits is still necessary. Through a comprehensive review of rabbit Fab crystal contacts and their incompatibility with human Fabs, we identified a small secondary structural element from the rabbit light chain constant domain potentially responsible for hindering the crystallization of human Fabs. Upon replacing the human kappa constant domain FG loop (HQGLSSP) with the two residue shorter rabbit loop (QGTTS), we dramatically improved the crystallization of human Fabs and Fab:antigen complexes. Our design, which we call "Crystal Kappa", enables rapid crystallization of human fabs and fab complexes in a broad range of conditions, with less material in smaller screens or from dilute solutions
Indole Glucocorticoid Receptor Antagonists Active in a Model of Dyslipidemia Act via a Unique Association with an Agonist Binding Site.
To further elucidate the structural
activity correlation of glucocorticoid
receptor (GR) antagonism, the crystal structure of the GR ligand-binding
domain (GR LBD) complex with a nonsteroidal antagonist, compound <b>8</b>, was determined. This novel indole sulfonamide shows in
vitro activity comparable to known GR antagonists such as mifepristone,
and notably, this molecule lowers LDL (−74%) and raises HDL
(+73%) in a hamster model of dyslipidemia. This is the first reported
crystal structure of the GR LBD bound to a nonsteroidal antagonist,
and this article provides additional elements for the design and pharmacology
of clinically relevant nonsteroidal GR antagonists that may have greater
selectivity and fewer side effects than their steroidal counterparts
Indole Glucocorticoid Receptor Antagonists Active in a Model of Dyslipidemia Act via a Unique Association with an Agonist Binding Site.
To further elucidate the structural
activity correlation of glucocorticoid
receptor (GR) antagonism, the crystal structure of the GR ligand-binding
domain (GR LBD) complex with a nonsteroidal antagonist, compound <b>8</b>, was determined. This novel indole sulfonamide shows in
vitro activity comparable to known GR antagonists such as mifepristone,
and notably, this molecule lowers LDL (−74%) and raises HDL
(+73%) in a hamster model of dyslipidemia. This is the first reported
crystal structure of the GR LBD bound to a nonsteroidal antagonist,
and this article provides additional elements for the design and pharmacology
of clinically relevant nonsteroidal GR antagonists that may have greater
selectivity and fewer side effects than their steroidal counterparts
Glucocorticoid Receptor Modulators Informed by Crystallography Lead to a New Rationale for Receptor Selectivity, Function, and Implications for Structure-Based Design
The structural basis
of the pharmacology enabling the use of glucocorticoids
as reliable treatments for inflammation and autoimmune diseases has
been augmented with a new group of glucocorticoid receptor (GR) ligands.
Compound <b>10</b>, the archetype of a new family of dibenzoxepane
and dibenzosuberane sulfonamides, is a potent anti-inflammatory agent
with selectivity for the GR versus other steroid receptors and a differentiated
gene expression profile versus clinical glucocorticoids (lower GR
transactivation with comparable transrepression). A stereospecific
synthesis of this chiral molecule provides the unique topology needed
for biological activity and structural biology. In vivo activity of <b>10</b> in acute and chronic models of inflammation is equivalent
to prednisolone. The crystal structure of compound <b>10</b> within the GR ligand binding domain (LBD) unveils a novel binding
conformation distinct from the classic model adopted by cognate ligands.
The overall conformation of the GR LBD/<b>10</b> complex provides
a new basis for binding, selectivity, and anti-inflammatory activity
and a path for further insights into structure-based ligand design
Computationally Designed Bispecific Antibodies using Negative State Repertoires
A challenge in the structure-based design of specificity is modeling the negative states, i.e. the complexes that you do not want to form. This is a difficult problem because mutations predicted to destabilize the negative state might be accommodated by small conformational rearrangements. To overcome this challenge, we employ an iterative strategy that cycles between sequence design and protein docking in order to build up an ensemble of alternative negative state conformations for use in specificity prediction. We have applied our technique to the design of heterodimeric C(H)3 interfaces in the Fc region of antibodies. Combining computationally- and rationally-designed mutations produced unique designs with heterodimer purities greater than 90%. Asymmetric Fc crystallization was able to resolve the interface mutations; the heterodimer structures confirmed that the interfaces formed as designed. With these C(H)3 mutations, and those made at the heavy-/light-chain interface, we demonstrate one-step synthesis of four fully IgG bispecific antibodies