Discovery of LNP1892: A Precision Calcimimetic for the Treatment of Secondary Hyperparathyroidism.

The calcium sensing receptor (CaSR) plays an important role in maintaining calcium homeostasis. The use of calcimimetic cinacalcet has been established to activate CaSR and normalize hypercalcemia. However, cinacalcet has limitations due to its high cLogP and pKa. A systematic optimization of cinacalcet to reduce its cLogP and pKa yielded compound 23a (LNP1892). Compound 23a showed excellent potency and a favorable pharmacokinetics profile, and lacked the liabilities of cinacalcet, making it a highly differentiated precision calcimimetic. In adenine-diet-induced chronic kidney disease (CKD) models, 23a demonstrated robust and dose-dependent efficacy, as measured by plasma parathyroid hormone (PTH) levels. It also showed an excellent safety profile in animal studies. Phase 1 clinical trials with 23a in healthy volunteers confirmed its excellent safety, tolerability, and effectiveness in lowering PTH levels in a dose-dependent manner, without causing symptomatic hypocalcaemia. Encouraged by these promising results, LNP1892 was taken to a Phase 2 study in CKD patients.

Discovery of a Potent and Selective PI3Kδ Inhibitor (S)-2,4-Diamino-6-((1-(7-fluoro-1-(4-fluorophenyl)-4-oxo-3-phenyl-4H-quinolizin-2-yl)ethyl)amino)pyrimidine-5-carbonitrile with Improved Pharmacokinetic Profile and Superior Efficacy in Hematological Cancer Models.

PI3Kδ inhibitors have been approved for B-cell malignancies like CLL, small lymphocytic lymphoma, and so forth. However, currently available PI3Kδ inhibitors are nonoptimal, showing weakness against at least one of the several important properties: potency, isoform selectivity, and/or pharmacokinetic profile. To come up with a PI3Kδ inhibitor that overcomes all these deficiencies, a pharmacophoric expansion strategy was employed. Herein, we describe a systematic transformation of a "three-blade propeller" shaped lead, 2,3-disubstituted quinolizinone 11, through a 1,2-disubstituted quinolizinone 20 to a novel "four-blade propeller" shaped 1,2,3-trisubstituted quinolizinone 34. Compound 34 has excellent potency, isoform selectivity, metabolic stability across species, and exhibited a favorable pharmacokinetic profile. Compound 34 also demonstrated a differentiated efficacy profile in human germinal center B and activated B cell-DLBCL cell lines and xenograft models. Compound 34 qualifies for further evaluation as a candidate for monotherapy or in combination with other targeted agents in DLBCLs and other forms of iNHL.