Pfkfb3 inhibitor and methods of use as an anti-cancer therapeutic

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A novel compound, (E)-1-(pyridyn-4-yl)-3-(7-(trifluoromethyl)quinolin-2-yl)-prop-2-en-1-one, is provided herein. (E)-1-(pyridyn-4-yl)-3-(7-(trifluoromethyl)quinolin-2-yl)-prop-2-en-1-one is an inhibitor of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) with surprisingly superior efficacy and pharmacodynamic properties in vitro and in vivo. Also provided are pharmaceutical compositions including the compound and methods of use of the compound in treating cancer and tumors in vivo, as well as inhibiting glycolytic flux and PFKFB3 enzymatic activity in cells.

The glycolytic pathway is a ten-step series of reactions that forms the major metabolic pathway in nearly all organisms. Flux through the glycolytic pathway is adjusted in response to conditions both inside and outside the cell. Irreversible glycolytic reactions are those catalyzed by hexokinase, phosphofructokinase, and pyruvate kinase. In metabolic pathways, such enzymes are potential targets for control, and all three enzymes serve this purpose in glycolysis. The PFKFB enzymes (PFKFB 1- 4) synthesize fructose-2,6-bisphosphate (F2,6BP) which activates 6-phosphofructo-l- kinase (PFK-1), an essential control point in the glycolytic pathway.

Neoplastic cells preferentially utilize glycolysis to satisfy their increased needs for energy and biosynthetic precursors. Malignant tumor cells have glycolytic rates that are up to 200 times higher than those of their normal tissues of origin. One cancer attack strategy has been to treat cancer by starving cancerous cells in various ways. Reducing or blocking the enhanced glycolytic flux mechanism present in cancer cells has stimulated recent interest. Despite greater understanding and pharmaceutical advances in the diagnosis and treatment of cancer, it is still estimated that nearly 13% of all human deaths last year were due to cancer. Thus, there remains a need for safe and effective anti-cancer therapeutics, particularly those which target neoplastic cells via mechanisms such as glycolytic flux, which are over-expressed in cancer cells.

Several maximum tolerated dose studies and toxicology studies were performed and the results indicated PFK-158 is safer than PFK-015. Studies were performed in C57/B16 mice and SD rats. Maximum Tolerated Doses (MTDs) were determined by either a body weight loss superior to 10% or death of animals during the study using a 3 days on/3 days off schedule. For PFK-158, the MTD was not reached and was thus defined as >45 mg/kg, while the MTD for PFK-015 was significantly lower, at 30 mg/kg. See Table 4, below.

Toxicology studies were performed in SD rats comparing PFK-158 and PFK-015 using a repeat dosing schedule. The studies were performed at dose levels ranging from 5 to 30 mg/kg and animals were monitored for weight loss, behavior, clinical signs, and clinical chemistries. At the end of the study, gross pathology and histopathology were performed. There were no adverse observations for PFK-158 for any of the tests performed, indicating that PFK-158 was very well tolerated and that the MTD would be higher than 30 mg/kg. The same study was conducted for PFK-015 at 2 dose levels (12 and 25 mg/kg), and adverse observations at both dose levels included body weight loss, decrease food consumption, clinical lethargy, increase in leukocyte, lymphocyte and neutrophil counts, macroscopic and microscopic findings, clinical pathology findings, and death. Based on these results, the MTD for PFK-015 in rats was determined to be 12 mg/kg. The difference in MTD values between the two compounds is unexpected and was not predicted from the pharmacokinetic profiles. Toxicology studies indicate PFK- 158 is significantly safer than the structurally similar PFK-015.

Studies determining efficacy of PFK-158 at inhibiting tumor growth in mouse cancer models were performed. These studies were carried out with PFK-158 alone and in combination with compounds currently used in the treatment of cancer patients.

Studies were performed in a lung cancer model, a pancreatic cancer model, and in a colon cancer model. In each case, the compound of the invention exhibited significant activity with tumor growth inhibition ranging from 50% to 70%, anti-tumor activity comparable to the controls used in those studies (chemotherapeutic agents used clinically to treat these tumor types such as paclitaxel, gemcitabine, and irinotican), without noticeable body weight loss or death (see Example 4 and Figures 6-8). Animals treated with PFK-015 exhibited similar activity but treatment was not as well tolerated, as body weight loss higher than 15% was observed, together with other clinical observations indicating adverse side effects. PFK-158 is better tolerated and safer than the structurally similar PFK-015. This tolerability benefit is significant, as it allows the combination of different anti-cancer compounds to increase tumor growth inhibition without increasing lethal side effects that minimize the benefits of such combinations.

Further, the solubility properties of PFK-158 are such that, if required, the compound can be administered using either a phospho-lipidic aqueous based emulsion, or in an emulsifier-free, solvent-free aqueous based solution. Surprisingly, the compound according to the invention does not, in the formulation mentioned above, undergo a rapid photoisomerization in these solutions. Hence, the unexpected added benefit simplifies administration to patients suffering from cancer or an autoimmune disease and does not necessarily require amber tubings or over-pouches to reduce UV exposure. I. Compound In one embodiment, the compound (E)-l-(pyridyn-4-yl)-3-(7- (trifluoromethyl)quinolin-2-yl)-prop-2-en-l-one is provided, having the following structural formula:and includes any pharmaceutically acceptable salts, isomers, prodrugs, or metabolites thereof.