Eric D. Moher

Cryptophycins-309, 249 and other cryptophycin analogs: preclinical efficacy studies with mouse and human tumors.

SummaryCryptophycins-1 and 52 (epoxides) were discovered to have in-vitro and in-vivo antitumor activity in the early 1990s. The chlorohydrins of these, Cryptophycins-8 and 55 (also discovered in the early 1990s) were markedly more active, but could not be formulated as stable solutions. With no method to adequately stabilize the chlorohydrins at the time, Cryptophycin-52 (LY 355073) entered clinical trials, producing only marginal antitumor activity. Since that time, glycinate esters of the hydroxyl group of the chlorohydrins have been synthesized and found to provide stability. Three of the most active were compared herein. Cryptophycin-309 (C-309) is a glycinate ester of the chlorohydrin Cryptophycin-296. The glycinate derivative provided both chemical stability and improved aqueous solubility. After the examination of 81 different Cryptophycin analogs in tumor bearing animals, C-309 has emerged as superior to all others. The following %T/C and Log Kill (LK) values were obtained from a single course of IV treatment (Q2d × 5) against early staged SC transplantable tumors of mouse and human origin: Mam 17/Adr [a pgp (+) MDR tumor]: 0%T/C, 3.2 LK; Mam 16/C/Adr [a pgp (−) MDR tumor]: 0%T/C, 3.3 LK; Mam 16/C: 0%T/C, 3.8 LK; Colon 26: 0%T/C, 2.2 LK; Colon 51: 0%T/C, 2.4 LK; Pancreatic Ductal Adenocarcinoma 02 (Panc 02): 0%T/C, 2.4 LK; Human Colon HCT15 [a pgp (+) MDR tumor]: 0%T/C, 3.3 LK; Human Colon HCT116: 0%T/C, 4.1 LK. One additional analog, Cryptophycin-249 (C-249, the glycinate of Cryptophycin-8), also emerged with efficacy rivaling or superior to C-309. However, there was sufficient material for only a single C-249 trial in which a 4.0 LK was obtained against the multidrug resistant breast adenocarcinoma Mam-16/C/Adr. C-309 and C-249 are being considered as second-generation clinical candidates.

Synthesis and biological evaluation of cryptophycin analogs with substitution at C-6 (fragment C region).

Analogs of the antitumor agents cryptophycins 1 and 8 with dialkyl substitution at C-6 (fragment C) were synthesized and evaluated for in vitro cytotoxicity against human leukemia cells (CCRF-CEM). The activity of these analogs decreased as the size of the substituents at C-6 increased. The C-6 spirocylopropyl compound (2g) was highly potent in vitro and showed excellent antitumor activity in animal models.

Novel asymmetric synthesis of a bicyclo[3.1.0]hexane derivative by an efficient retro-diels-alder strategy

Abstract The first preparation of enantiomerically pure bicyclo[3.1.0]hexane-2-one-6-carboxylic acid ethyl ester ( 1 ), a valuable synthetic intermediate, is described. The synthesis features a retro-Diels-Alder reaction as a key step. Conditions which allow for a high yielding thermal conversion of 3 to 4 are described.

Mechanistic investigation of a Ru-catalyzed direct asymmetric reductive amination reaction for a batch or continuous process scale-up: an industrial perspective

A comprehensive assessment of a Ru-catalyzed direct asymmetric reductive amination (DARA) reaction for producing an intermediate for an active pharmaceutical ingredient (API) was carried out. Experiments were conducted to investigate the impact of process parameters (such as reaction temperature, time, concentration, pressure, Ru-catalyst concentration, acid catalyst, and reagent stoichiometry) on chemo- and stereo-selectivity, and yield. An analysis of experimental data led to the development of a mechanistic mathematical model that was mathematically consistent with data from laboratory development and manufacturing campaigns. A combinatory approach outlined herein could be used to provide the optimum conditions for the DARA process. Furthermore, the feasible operating region was mapped out, which highlighted the complexity of the investigated chemistry and aided in developing the control strategy and regulatory submission package pertinent to this reaction. The efforts allowed the process to be successfully validated and scaled using a plug flow reactor (PFR) to manufacture 3200 kg of (S)-7,9-dimethyl-N-(2-methyl-2H-tetrazol-5-yl)-2,3,4,5-tetrahydro-1H-benzo[b]azepin-5-amine under current Good Manufacturing Practice (cGMP).