ZOMIB SERIES

1. MARIZOMIB

2 BORTEZOMIB
3CARFILZOMIB
4
5
WILL BE UPDATED

1  MARIZOMIB, Salinosporamide A

DECEMBER 30, 2013 8:07 AM / 1 COMMENT / EDIT

MARIZOMIB
http://www.ama-assn.org/resources/doc/usan/marizomib.pdf
THERAPEUTIC CLAIM Antineoplastic
CHEMICAL NAMES
1. 6-Oxa-2-azabicyclo[3.2.0]heptane-3,7-dione, 4-(2-chloroethyl)-1-[(S)-(1S)-2-
cyclohexen-1-ylhydroxymethyl]-5-methyl-, (1R,4R,5S)-
2. (1R,4R,5S)-4-(2-chloroethyl)-1-{(S)-[(1S)-cyclohex-2-en-1-yl]hydroxymethyl}-5-methyl-
6-oxa-2-azabicyclo[3.2.0]heptane-3,7-dione
MOLECULAR FORMULA C15H20ClNO4
MOLECULAR WEIGHT 313.8
MANUFACTURER Nereus Pharmaceuticals, Inc.
NOTE….Nereus Pharmaceuticals was acquired by Triphase Research and Development in 2012.
CODE DESIGNATION NPI-0052
CAS REGISTRY NUMBER 437742-34-2
Scripps Institution of Oceanography (Originator)
mp, 168–170° C. (authentic sample: 168–170° C., 169–171° C. in Angew. Chem. Int. Ed., 2003, 42, 355–357); mixture mp, 168–170C.
[α]23 D −73.2 (c 0.49, MeOH), −72.9 (c 0.55, MeOH, in Angew. Chem. Int. Ed., 2003, 42, 355–357);
FTIR (film) νmax: 3406, 2955, 2920, 2844, 1823, 1701, 1257, 1076, 1012, 785, 691 cm−1;
1H NMR (CDCl3, 500 MHz): δ 10.62 (1H, br), 6.42 (1H, d, J=10.5 Hz), 5.88 (1H, m), 4.25 (1H, d, J=9.0 Hz), 4.14 (1H, m), 4.01 (1H, m), 3.17 (1H, t, J=7.0 Hz), 2.85 (1H, m), 2.48 (1H, m), 2.32 (2H, m), 2.07 (3H, s), 1.91 (2H, m), 1.66 (2H, m), 1.38 (1H, m);
13C NMR (CDCl3, 125 MHz): δ 176.92, 169.43, 129.08, 128.69, 86.32, 80.35, 70.98, 46.18, 43.28, 39.31, 29.01, 26.47, 25.35, 21.73, 20.00;
HRMS (ESI) calcd. for (M−H)− C15H19ClNO4 312.1003, found 312.1003.
Marizomib, a highly potent proteasome inhibitor, is in early clinical development at Triphase Research and Development I Corp for the treatment of relapsed or relapsed/refractory multiple myeloma. Phase I clinical trials have also been carried out for the treatment of solid tumors and lymphoma; however, no recent developments have been reported for these studies.
HDAC inhibitors halt tumor cell differentiation and growth, and when combined with marizomib in preclinical in vitro and in vivo studies, show additive and synergistic antitumor activities.
The compound was discovered from a new marine-obligate gram-positive actinomycete (Salinispora tropica). Preclinical studies suggest that this next-generation compound may be superior to other proteasome inhibitors, with broader target inhibition, faster onset and longer duration of action, higher potency, and oral and intravenous availability. By inhibiting proteasomes, marizomib prevents the breakdown of proteins involved in signal transduction, which blocks growth and induces apoptosis in cancer cells.
In 2013, orphan drug designation was assigned in the U.S. for the treatment of multiple myeloma.
The compound was originally developed by Nereus Pharmaceuticals, which was acquired by Triphase Research and Development in 2012.
marizomib is a naturally-occurring salinosporamide, isolated from the marine actinomycete Salinospora tropica, with potential antineoplastic activity. Marizomib irreversibly binds to and inhibits the 20S catalytic core subunit of the proteasome by covalently modifying its active site threonine residues; inhibition of ubiquitin-proteasome mediated proteolysis results in an accumulation of poly-ubiquitinated proteins, which may result in the disruption of cellular processes, cell cycle arrest, the induction of apoptosis, and the inhibition of tumor growth and angiogenesis. This agent more may more potent and selective than the proteasome inhibitor bortezomib
Marizomib (NPI-0052) is an oral, irreversible ββ-lactone derivative that binds selectively to the active proteasomal sites. In vivo studies with marizomib demonstrate reduced tumor growth without significant toxicity in myeloma xenograft models. A phase I trial in refractory and relapsed MM is under way.
Salinosporamide A is a potent proteasome inhibitor used as an anticancer agent that recently entered phase I human clinical trials for the treatment of multiple myeloma only three years after its discovery.[1][2] This novel marine natural product is produced by the recently described obligate marine bacteria Salinispora tropica and Salinispora arenicola, which are found in ocean sediment. Salinosporamide A belongs to a family of compounds, known collectively as salinosporamides, which possess a densely functionalized γ-lactam-β-lactone bicyclic core.
Salinosporamide A was discovered by William Fenical and Paul Jensen from Scripps Institution of Oceanography in La Jolla, CA. In preliminary screening, a high percentage of the organic extracts of cultured Salinospora strains possessed antibiotic and anticancer activities, which suggests that these bacteria are an excellent resource for drug discovery.Salinospora strain CNB-392 was isolated from a heat-treated marine sediment sample and cytotoxicity-guided fractionation of the crude extract led to the isolation of salinosporamide A. Although salinosporamide A shares an identical bicyclic ring structure with omuralide, it is uniquely functionalized. Salinosporamide A displayed potent in vitro cytotoxicity against HCT-116 human colon carcinoma with an IC50 value of 11 ng mL-1. This compound also displayed potent and highly selective activity in the NCI’s 60-cell-line panel with a mean GI50 value (the concentration required to achieve 50% growth inhibition) of less than 10 nM and a greater than 4 log LC50 differential between resistant and susceptible cell lines. The greatest potency was observed against NCI-H226 non-small cell lung cancer, SF-539 CNS cancer, SK-MEL-28 melanoma, and MDA-MB-435 breast cancer (all with LC50 values less than 10 nM). Salinosporamide A was tested for its effects on proteasome function because of its structural relationship to omuralide. When tested against purified 20S proteasome, salinosporamide A inhibited proteasomal chymotrypsin-like proteolytic activity with an IC50 value of 1.3 nM.[3] This compound is approximately 35 times more potent than omuralide which was tested as a positive control in the same assay. Thus, the unique functionalization of the core bicyclic ring structure of salinosporamide A appears to have resulted in a molecule that is a significantly more potent proteasome inhibitor than omuralide.[1]

Salinosporamide A inhibits proteasome activity by covalently modifying the active site threonine residues of the 20S proteasome.

Biosynthesis


Salinosporamide A and B building blocks

Proposed biosynthesis of the nonproteinogenic amino-acid beta-hydroxycyclohex-2′-enylanine (3) (R = H or S~PCP) via a shunt in the phenylalanine biosynthetic pathway

Biosynthesis
It was originally hypothesized that salinosporamide B was a biosynthetic precursor to salinosporamide A due to their structural similarities.
It was thought that the halogenation of the unactivated methyl group was catalyzed by a non-heme iron halogenase.[4][5]Recent work using 13C-labeled feeding experiments reveal distinct biosynthetic origins of salinosporamide A and B.[4][6]
While they share the biosynthetic precursors acetate and presumed β-hydroxycyclohex-2′-enylalanine (3), they differ in the origin of the four-carbon building block that gives rise to their structural differences involving the halogen atom. A hybrid polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) pathway is most likely the biosynthetic mechanism in which acetyl-CoA and butyrate-derived ethylmalonyl-CoA condense to yield the β-ketothioester (4), which then reacts with (3) to generate the linear precursor (5).

The first stereoselective synthesis was reported by Rajender Reddy Leleti and E. J.Corey.[7] Later several routes to the total synthesis of salinosporamide A have been reported.[7][8][9][10]

In vitro studies using purified 20S proteasomes showed that salinosporamide A has lower EC50 for trypsin-like (T-L) activity than does Bortezomib. In vivo animal model studies show marked inhibition of T-L activity in response to salinosporamide A, whereas bortezomib enhances T-L proteasome activity.
Initial results from early-stage clinical trials of salinosporamide A in relapsed/refractory multiple myeloma patients were presented at the 2011 American Society of Hematology annual meeting.[11] Further early-stage trials of the drug in a number of different cancers are ongoing.[12]

  1.  Feling RH, Buchanan GO, Mincer TJ, Kauffman CA, Jensen PR, Fenical W (2003). “Salinosporamide A: a highly cytotoxic proteasome inhibitor from a novel microbial source, a marine bacterium of the new genus salinospora”. Angew. Chem. Int. Ed. Engl. 42 (3): 355–7.doi:10.1002/anie.200390115. PMID 12548698.
  2.  Chauhan D, Catley L, Li G et al. (2005). “A novel orally active proteasome inhibitor induces apoptosis in multiple myeloma cells with mechanisms distinct from Bortezomib”. Cancer Cell 8 (5): 407–19.doi:10.1016/j.ccr.2005.10.013. PMID 16286248.
  3.  K. Lloyd, S. Glaser, B. Miller, Nereus Pharmaceuticals Inc.
  4.  Beer LL, Moore BS (2007). “Biosynthetic convergence of salinosporamides A and B in the marine actinomycete Salinispora tropica”. Org. Lett. 9 (5): 845–8.doi:10.1021/ol063102o. PMID 17274624.
  5.  Vaillancourt FH, Yeh E, Vosburg DA, Garneau-Tsodikova S, Walsh CT (2006). “Nature’s inventory of halogenation catalysts: oxidative strategies predominate”. Chem. Rev.106 (8): 3364–78. doi:10.1021/cr050313i.PMID 16895332.
  6.  Tsueng G, McArthur KA, Potts BC, Lam KS (2007). “Unique butyric acid incorporation patterns for salinosporamides A and B reveal distinct biosynthetic origins”. Applied Microbiology and Biotechnology 75 (5): 999–1005. doi:10.1007/s00253-007-0899-7.PMID 17340108.
  7.  Reddy LR, Saravanan P, Corey EJ (2004). “A simple stereocontrolled synthesis of salinosporamide A”. J. Am. Chem. Soc. 126 (20): 6230–1. doi:10.1021/ja048613p.PMID 15149210.
  8.  Ling T, Macherla VR, Manam RR, McArthur KA, Potts BC (2007). “Enantioselective Total Synthesis of (-)-Salinosporamide A (NPI-0052)”.Org. Lett. 9 (12): 2289–92. doi:10.1021/ol0706051. PMID 17497868.
  9.  Ma G, Nguyen H, Romo D (2007). “Concise Total Synthesis of (±)-Salinosporamide A, (±)-Cinnabaramide A, and Derivatives via a Bis-Cyclization Process: Implications for a Biosynthetic Pathway?”. Org. Lett. 9 (11): 2143–6. doi:10.1021/ol070616u. PMC 2518687.PMID 17477539.
  10.  Endo A, Danishefsky SJ (2005). “Total synthesis of salinosporamide A”. J. Am. Chem. Soc. 127 (23): 8298–9.doi:10.1021/ja0522783. PMID 15941259.
  11.  “Marizomib May Be Effective In Relapsed/Refractory Multiple Myeloma (ASH 2011)”. The Myeloma Beacon. 2012-01-23. Retrieved 2012-06-10.
  12.  ClinicalTrials.gov: Marizomib
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IMPORTANT PAPERS
Total synthesis of salinosporamide A
Org Lett 2008, 10(19): 4239
Entry to heterocycles based on indium-catalyzed conia-ene reactions: Asymmetric synthesis of (-)-salinosporamide A
Angew Chem Int Ed 2008, 47(33): 6244
A concise and straightforward total synthesis of (+/-)-salinosporamide A, based on a biosynthesis model
Org Biomol Chem 2008, 6(15): 2782
Formal synthesis of salinosporamide A starting from D-glucose
Synthesis (Stuttgart) 2009, 2009(17): 2983
Stereoselective functionalization of pyrrolidinone moiety towards the synthesis of salinosporamide A
Tetrahedron 2012, 68(32): 6504
………………
Salinosporamide A(1) was recently discovered by Fenical et al. as a bioactive product of a marine microorganism that is widely distributed in ocean sediments. Feeling, R. H.; Buchanan, G. O.; Mincer, T. J.; Kauffman, C. A.; Jensen, P. R.; Fenical, W., Angew. Chem. Int. Ed., 2003, 42, 355–357.
Figure US07183417-20070227-C00002
Structurally Salinosporamide A closely resembles the terrestrial microbial product omuralide (2a) that was synthesized by Corey et al. several years ago and demonstrated to be a potent inhibitor of proteasome function. See, (a) Corey, E. J.; Li, W. D., Z. Chem. Pharm. Bull., 1999, 47, 1–10; (b) Corey, E. J., Reichard, G. A.; Kania, R., Tetrahedron Lett., 1993, 34, 6977–6980; (c) Corey, E. J.; Reichard, G. A., J. Am. Chem. Soc., 1992, 114, 10677–10678; (d) Fenteany, G.; Standaert, R. F.; Reichard, G. A.; Corey, E. J.; Schreiber, S. L., Proc. Natl. Acad. Sci. USA, 1994, 91, 3358–3362.
Omuralide is generated by β-lactonization of the N-acetylcysteine thiolester lactacystin (2b) that was first isolated by the Omura group as a result of microbial screening for nerve growth factor-like activity. See, Omura, S., Fujimoto, T., Otoguro, K., Matsuzaki, K., Moriguchi, R., Tanaka, H., Sasaki, Y., Antibiot., 1991, 44, 113–116; Omura, S., Matsuzaki, K., Fujimoto, T., Kosuge, K., Furuya, T., Fujita, S., Nakagawa, A., J. Antibiot., 1991, 44, 117–118.
Salinosporamide A, the first compound Fenical’s group isolated from Salinospora, not only had a never-before-seen chemical structure 1, but is also a highly selective and potent inhibitor of cancer-cell growth. The compound is an even more effective proteasome inhibitor than omuralide and, in addition, it displays surprisingly high in vitro cytotoxic activity against many tumor cell lines (IC50values of 10 nM or less). Fenical et al. first found the microbe, which they’ve dubbed Salinospora, off the coasts of the Bahamas and in the Red Sea. See,Appl. Environ. Microbiol., 68, 5005 (2002).
Fenical et al. have shown that Salinospora species requires a salt environment to live. Salinospora thrives in hostile ocean-bottom conditions: no light, low temperature, and high pressure. The Fenical group has now identified Salinosporain five oceans, and with 10,000 organisms per cm3 of sediment and several distinct strains in each sample; and according to press reports, they’ve been able to isolate 5,000 strains. See, Chemical & Engineering News, 81, 37 (2003).
A great percentage of the cultures Fenical et al. have tested are said to have shown both anticancer and antibiotic activity. Like omuralide 2a, salinosporamide A inhibits the proteasome, an intracellular enzyme complex that destroys proteins the cell no longer needs. Without the proteasome, proteins would build up and clog cellular machinery. Fast-growing cancer cells make especially heavy use of the proteasome, so thwarting its action is a compelling drug strategy. See, Fenical et al., U.S. Patent Publication No. 2003-0157695A1
PATENTS
WO 2005113558
Part I. Synthesis of the Salinosporamide A(1)
EXAMPLE 1
Figure US07183417-20070227-C00016
(4S, 5R) Methyl 4,5-dihydro-2 (4-methoxyphenyl)-5-methyloxazole-4-carboxylate (4)
A mixture of (2S, 3R)-methyl 2-(4-methoxybenzamido)-3-hydroxybutanoate (3) (35.0 g, 131 mmol) and p-TsOH.H2O (2.5 g, 13.1 mmol) in toluene (400 mL) was heated at reflux for 12 h. The reaction mixture was diluted with water (200 mL) and extracted with EtOAc (3×200 mL). The combined organic layers were washed with water, brine and dried over Na2SO4. The solvent was removed in vacuo to give crude oxazoline as yellow oil. Flash column chromatography on silica gel (eluent 15% EtOAc-Hexanes) afforded the pure oxazoline (26.1 g, 80%) as solid.
Rf=0.51 (50% ethyl acetate in hexanes), mp, 86–87° C.; [α]23 D+69.4 (c 2.0, CHCl3); FTIR (film) νmax: 2955, 1750, 1545, 1355, 1187, 1011, 810 cm−1; 1HNMR(CDCl3, 400 MHz): δ 7.87 (2H, d, J=9.2 Hz), 6.84 (2H, d, J=8.8 Hz), 4.90 (1H, m), 4.40 (1H, d, J=7.6 Hz), 3.79 (3H,s), 3.71 (3H, s), 1.49 (3H, d, J=6.0 Hz); 13C NMR (CDCl3, 100 MHz): δ 171.93, 165.54, 162.64, 130.52, 119.80, 113.85, 78.91, 75.16, 55.51, 52.73, 21.14; HRMS (ESI) calcd for C13H16NO4 (M+H)+.250.1079, found 250.1084.
EXAMPLE 2
Figure US07183417-20070227-C00017
(4R, 5R)-Methyl 4-{(benzyloxy) methyl)}-4,5-dihydro-2-(4-methoxyphenyl)-5-methyloxazole-4-carboxylate (5)
To a solution of LDA (50 mmol, 1.0 M stock solution in THF) was added HMPA (24 mL, 215 mmol) at −78° C. and then oxazoline 4 (12.45 g, 50 mmol, in 20 mL THF) was added dropwise with stirring at −78° C. for 1 h to allow complete enolate formation. Benzyloxy chloromethyl ether (8.35 mL, 60 mmol) was added at this temperature and after stirring the mixture at −78° C. for 4 h, it was quenched with water (50 mL) and warmed to 23° C. for 30 min. Then the mixture was extracted with ethyl acetate (3×50 mL) and the combined organic phases were dried (MgSO4) and concentrated in vacuo. The crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:4 then 1:3) to give the benzyl ether 5 (12.7 g, 69%).
Rf=0.59 (50% ethyl acetate in hexanes). [α]23 D−6.3 (c 1.0, CHCl3); FTIR (film) (νmax; 3050, 2975, 1724, 1642, 1607, 1252, 1027, 745, 697 cm−1; 1H NMR (CDCl3, 400 MHz): δ 7.96 (2H, d, J=9.2 Hz), 7.26 (5H, m), 6.90 (2H, J=8.8 Hz), 4.80 (1H, m), 4.61 (2H, s), 3.87 (3H, m), 3.81 (3H, s), 3.73 (3H, s), 1.34 (3H, d, J=6.8 Hz); 13C NMR (CDCl3, 100 MHZ): 6171.23, 165.47, 162.63, 138.25, 130.64, 128.52, 127.87, 127.77, 120.15, 113.87, 81.40, 79.92, 73.91, 73.43, 55.58, 52.45, 16.92; HRMS (ESI) calcd for C21H24O5 (M+H)+370.1654, found 370.1644.
EXAMPLE 3
Figure US07183417-20070227-C00018
(2R,3R)-Methyl 2-(4-methoxybenzylamino)-2-((benzyloxy)methyl)-3hydroxybutanoate (6)
To a solution of oxazoline 5 (18.45 g, 50 mmol) in AcOH (25 mL) at 23° C. was added in portions NaCNBH3 (9.3 g, 150 mmol). The reaction mixture was then stirred at 40° C. for 12 h to allow complete consumption of the starting material. The reaction mixture was diluted with water (100 mL), neutralized with solid Na2CO3 and the aqueous layer was extracted with ethyl acetate (3×100 mL). The combined organic phases were dried over NaSO4 and concentrated in vacuo. The crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:5) to give the N-PMB amino alcohol 6 (16.78 g, 90%).
Rf=0.50 (50% ethyl acetate in hexanes). [α]23 D−9.1(c 1.0, CHCl3); FTIR (film) νmax; 3354, 2949, 1731, 1511, 1242, 1070, 1030, 820, 736, 697 cm−1; 1H NMR (CDCl3, 400 MHz): δ 7.32 (7H, m), 6.87 (2H, d, J=8.8 Hz), 4.55 (2H, m), 4.10 (1H, q, J=6.4 Hz), 3.85 (2H, dd, J=17.2, 10.0 Hz), 3.81 (3H, s,), 3.77 (3H, s), 3. 69 (2H, dd, J=22.8, 11.6 Hz), 3.22 (2H, bs), 1.16 (3H, d, J=6.0 Hz); 13C NMR (CDCl3, 100 MHz): δ 173.34, 159.03, 137.92, 132.51, 129.78, 128.67, 128.07, 127.98, 114.07, 73.80, 70.55, 69.82, 69.65, 55.51, 55.29, 47.68, 18.15; HRMS (ESI) calcd. for C21H28NO5 (M+H)+ 374.1967, found 374.1974.
EXAMPLE 4
Figure US07183417-20070227-C00019
(2R,3R)-Methyl-2-(N-(4-methoxybenzyl)acrylamido)-2-(benzyloxy)methyl)-3-hydroxybutanoate (7)
A solution of amino alcohol 6 (26.2 g, 68.5 mmol) in Et2O (200 mL) was treated with Et3N (14.2 mL, 102.8 mmol) and trimethylchlorosilane (10.4 mL, 82.2 mmol) at 23° C. and stirred for 12 h. After completion, the reaction mixture was diluted with ether (200 mL) and then resulting suspension was filtered through celite. The solvent was removed to furnish the crude product (31.2 g, 99%) in quantitative yield as viscous oil. A solution of this crude trimethylsilyl ether (31.1 g) in CH2Cl2 (200 mL) was charged with diisopropylethylamine (14.2 mL, 81.6 mmol) and then cooled to 0° C. Acryloyl chloride (6.64 mL, 82.2 mmol) was added dropwise with vigorous stirring and the reaction temperature was maintained at 0° C. until completion (1 h). The reaction mixture was then diluted with CH2Cl2 (100 mL) and the organic layer was washed with water and brine. The organic layer was separated and dried over Na2SO4. The solvent was removed to afford the crude acrylamide 7 as a viscous oil. The crude product was then dissolved in Et2O (200 mL) and stirred with 6N HCl (40 mL) at 23° C. for 1 h. The reaction mixture was diluted with water (100 mL) and concentrated to provide crude product. The residue was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:5 to 1:1) to give pure amide 7 (28.3 g, 96%) as colorless solid, mp 88–89° C.
Rf=0.40 (50% ethyl acetate in hexanes), [α]23 D−31.1 (c 0.45, CHCl3), FTIR (film) νmax; 3435, 2990, 1725, 1649, 1610, 1512, 1415, 1287, 1242, 1175, 1087, 1029, 732, 698 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.25 (5H, m), 7.15 (2H, d, J=6.0 Hz), 6.85 (2H, d, J=7.5 Hz), 6.38 (2H, d, J=6.0 Hz), 5.55 (1H, t, J=6.0 Hz), 4.81 (2H, s), 4.71 (1H, q, J=6.5 Hz), 4.35 (2H, s), 4.00 (1H, d, J=10.0 Hz), 3.80 (1H, d, J=10.0 Hz), 3.76 (3H, s), 3.75 (3H, s), 3.28 (1H, bs), 1.22 (3H, d, J=6.0 Hz); 13C NMR (CDCl3, 125 MHz): δ 171.87, 168.74, 158.81, 137.73, 131.04, 129.68, 128.58, 128.51, 127.94, 127.72, 127.20, 127.14, 114.21, 73.71, 70.42, 69.76, 67.65, 55.45, 52.52, 49.09, 18.88; HRMS (ESI) calcd. for C24H30NO6 (M+H)+428.2073, found 428.2073.
EXAMPLE 5
Figure US07183417-20070227-C00020
(R)-Methyl-2-(N-(4-methoxybenzyl)acrylamido)-2-(benzyloxy)methyl)-3-oxybutanoate (8)
To a solution of amide 7 (10.67 g, 25.0 mmol) in CH2Cl2 (100 mL) was added Dess-Martin periodinane reagent (12.75 g, 30.0 mmol, Aldrich Co.) at 23° C. After stirring for 1 h, the reaction mixture was quenched with aq NaHCO3—Na2S2O3 (1:1, 50 mL) and extracted with ethyl acetate (3×50 mL). The organic phase was dried and concentrated in vacuo to afford the crude ketone. The crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes) to give pure keto amide 8 (10.2 g, 96%).
Rf=0.80 (50% ethyl acetate in hexanes), mp 85 to 86° C.; [α]23 D−12.8 (c 1.45, CHCl3); FTIR (film) νmax: 3030, 2995, 1733, 1717, 1510, 1256, 1178, 1088, 1027, 733, 697 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.30 (2H, d, J=8.0), 7.25 (3H, m), 7.11 (2H, m), 6.88 (2H, d, J=9.0 Hz), 6.38 (2H, m), 5.63 (1H, dd, J=8.5, 3.5 Hz), 4.93 (1H, d, J=18.5 Hz), 4.78 (1H, d, J=18.5, Hz), 4.27 (2H, m), 3.78 (3H, s), 3.76 (3H, s), 2.42 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 198.12, 169.23, 168.62, 158.01, 136.95, 130.64, 130.38, 128.63, 128.13, 127.77, 127.32, 114.33, 77.49, 73.97, 70.66, 55.49, 53.09, 49.03, 28.24; HRMS (ESI) calcd. for C24H28NO6 (M+H)+ 426.1916, found 426.1909.
EXAMPLE 6
Figure US07183417-20070227-C00021
(2R,3S)-Methyl-1-(4-methoxybenzyl)-2-((benzyloxy)methyl)-3-hydroxy-3-methyl-4-methylene-5-oxopyrrolidine-2-carboxylate (9+10)
A mixture of keto amide 8 (8.5 g, 20.0 mmol) and quinuclidine (2.22 g, 20.0 mmol) in DME (10 mL) was stirred for 5 h at 23° C. After completion, the reaction mixture was diluted with ethyl acetate (50 mL) washed with 2N HCl, followed by water and dried over Na2SO4. The solvent was removed in vacuo to give the crude adduct (8.03 g, 94.5%, 3:1 ratio of 9 to 10 dr) as a viscous oil. The diastereomeric mixture was separated at the next step, although small amounts of 9 and 10 were purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:10 to 1:2) for analytical purposes.
Major Diastereomer (9).
[α]23 D−37.8 (c 0.51, CHCl3); FTIR (film) vmax: 3450, 3055, 2990, 1733, 1683, 1507, 1107, 1028, 808,734 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.29 (5H, m), 7.15 (2H, d, J=7.5 Hz), 6.74 (2H, d, J=8.5 Hz), 6.13 (1H, s), 5.57 (1H, s), 4.81 (1H, d, J=14.5 Hz), 4.45(1H, d, J=15.0 Hz), 4.20 (1H, d, J=12.0 Hz), 4.10 (1H, d, J=12.0 Hz) 3.75 (3H, s), 3.70 (1H, d, J=10.5 Hz), 3.64 (3H, s), 3.54 (1H, d, J=10.5 Hz), 2.55 (1H, bs, OH), 1.50 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 169.67, 168.42, 158.97, 145.96, 137.57, 130.19, 130.12, 128.53, 127.83, 127.44, 116.79, 113.71, 76.32, 76.00, 73.16, 68.29, 55.45, 52.63, 45.36, 22.64; HRMS (ESI) calcd. for C24H28NO6 (M+H)+ 426.1916, found 426.1915.
Minor Diastereomer (10).
[α]23 D−.50.1 (c 0.40, CHCl3); FTIR (film) νmax: 3450, 3055, 2990, 1733, 1683, 1507, 1107, 1028, 808, 734 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.29 (5H, m), 7.12 (2H, d, J=7.5 Hz), 6.73 (2H, d, J=8.5 Hz), 6.12 (1H, s), 5.57 (1H, s), 4.88 (1H, d, J=15.5 Hz), 4.31 (1H, d, J=15.0 Hz), 4.08 (3H, m), 3.99 (1H, d, J=12.0 Hz) 3.73 (3H, s), 3.62 (3H, s), 3.47 (1H, bs, OH), 3.43 (1H, d, J=10.0 Hz), 1.31 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 169.65, 167.89, 159.13, 147.19, 136.95, 130.29, 129.76, 128.74, 128.19, 127.55, 116.80, 113.82, 76.21, 75.66, 73.27, 68.02, 55.45, 52.52, 45.24, 25.25; HRMS (ESI) calcd. for (M+H)+ C24H28NO6 426.1916, found 426.1915.
EXAMPLE 7
Silylation of 9 and 10 and Purification of 11.
To a solution of lactams 9 and 10 (7.67 g, 18 mmol) in CH2Cl2 (25 ml) was added Et3N (7.54 ml, 54 mmol), and DMAP (2.2 g, 18 mmol) at 0° C., and then bromomethyl-dimethylchlorosilane (5.05 g, 27 mmol) (added dropwise). After stirring the mixture for 30 min at 0° C., it was quenched with aq NaHCO3 and the resulting mixture was extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with water, brine and dried over Na2SO4. The solvent was removed in vacuo to give a mixture of the silated derivatives of 9 and 10 (9.83 g, 95%). The diastereomers were purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:5 to 1:4) to give pure diastereomer 11 (7.4 g, 72%) and its diastereomer (2.4 g, 22%).
Silyl Ether (11).
Rf=0.80 (30% ethyl acetate in hexanes). [α]23 D−58.9 (c 0.55, CHCl3); FTIR (film) νmax; 3050, 2995, 1738, 1697, 1512, 1405, 1243, 1108, 1003, 809, 732 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.27 (5H, m), 7.05 (2H, d, J=7.0 Hz), 6.71 (2H, d, J=8.5 Hz), 6.18 (1H, s), 5.53 (1H, s), 4.95 (1H, d, J=15.5 Hz), 4.45 (1H, d, J=15.0 Hz), 4.02 (1H, J=12.0 Hz), 3.86 (1H, d, J=11.5 Hz) 3.72 (3H, s), 3.68 (3H, s), 3.65 (1H, d, J=10.5 Hz), 3.30 (1H, d, J=10.0 Hz), 2.34 (2H, d, J=2.0 Hz), 1.58 (3H, s), 0.19 (3H, s), 0.18 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 168.62, 168.12, 158.93, 145.24, 137.53, 130.32, 130.30, 128.49, 127.76,127.22, 117.26, 113.60, 78.55, 78.03, 72.89, 68.45, 55.43, 52.37, 45.74, 21.87, 17.32, −0.72, −0.80; HRMS (ESI) Calcd. for C27H35BrNO6Si (M+H)+ 576.1417, found 576.1407.
EXAMPLE 8
Figure US07183417-20070227-C00022
Conversion of (11) to (12).
To a solution of compound 11 (5.67 g 10 mmol) in benzene (250 mL) at 80° C. under nitrogen was added a mixture of tributyltin hydride (4.03 ml, 15 mmol) and AIBN (164 mg, 1 mmol) in 50 ml benzene by syringe pump over 4 h. After the addition was complete, the reaction mixture was stirred for an additional 4 h at 80° C. and the solvent was removed in vacuo. The residue was dissolved in hexanes (20 mL) and washed with saturated NaHCO3 (3×25 mL), water and dried over Na2SO4. The solvent was removed in vacuo to give crude product. The crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:5) to afford the pure 12 (4.42 g, 89%).
Rf=0.80 (30% ethyl acetate in hexanes). [α]23 D−38.8 (c 0.25, CHCl3); FTIR (film) νmax; 3025, 2985, 1756, 1692, 1513, 1247, 1177, 1059, 667 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.28 (5H, m), 7.09 (2H, d, J=7.0 Hz), 6.73 (2H, d, J=9.0 Hz), 4.96(1H, d, J=15.0 Hz), 4.35 (1H, d, J=15.5 Hz), 3.97 (1H, d, J=12.5 Hz), 3.86 (1H, d, J=12.0 Hz), 3.80 (1H, d, J=10.0 Hz), 3.72 (3H, s), 3.65 (3H, s), 3.27 (1H, d, J=10.5 Hz), 2.67 (1H, t, J=4.0 Hz), 2.41 (1H, m), 1.79 (1H, m), 1.46 (3H, s), 0.77 (1H, m), 0.46 (1H, m), 0.10 (3H, s), 0.19 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 175.48, 169.46, 158.76, 137.59, 131.04, 129.90, 128.58, 127.88, 127.52, 113.59, 113.60, 81.05, 78.88, 73.12, 69.03, 55.45, 51.94, 48.81, 45.50, 22.79, 17.06, 7.76, 0.54; HRMS (ESI) calcd. for (M+H)+ C27H36NO6Si 498.2312, found 498.2309.
EXAMPLE 9
Figure US07183417-20070227-C00023
Debenzylation of (12).
A solution of 12 (3.98 g, 8 mmol) in EtOH (50 ml) at 23° C. was treated with 10% Pd—C (˜1 g) under an argon atmosphere. The reaction mixture was evacuated and flushed with H2 gas (four times) and then stirred vigorously under an atmosphere of H2 (1 atm, H2 balloon) at 23° C. After 12 h, the reaction mixture was filtered through Celite and concentrated in vacuo to give the crude debenzylation product (3.08 g, 95%) which was used for the next step. A small amount crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:3) for analytical purposes. Rf=0.41 (50% ethyl acetate in hexanes).
mp, 45–47° C.; [α]23 D−30.9 (c 0.55, CHCl3); FTIR (film) νmax: 3432, 3020, 2926, 1735, 1692, 1512, 1244, 1174, 1094, 1024, 870, 795 cm−1; 1H NMR (CDCl3, 400 MHz): δ 7.36 (2H, d, J=8.5 Hz), 6.83 (2H, d, J=8.5 Hz), 5.16 (1H, d, J=15.0 Hz), 4.29 (1H, d, J=15.0 Hz), 3.92 (1H, m), 3.78 (3H, s), 3.68 (3H, s), 3.45 (1H, m), 2.53 (1H, t, J=4.0 Hz), 2.42 (1H, m), 1.82 (1H, m), 1.50 (3H, s), 1.28 (1H, m), 0.75 (1H, m), 0.47 (1H, m), 0.11 (3H, s), 0.02 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 175.82, 169.51, 159.32, 131.00, 129.72, 114.52, 80.79, 80.13, 61.85, 55.48, 51.99, 49.29, 45.06, 23.11, 17.03, 7.44, 0.54; HRMS (ESI) calcd. for C20H30NO6Si (M+H)+ 408.1842, found 408.1846.
EXAMPLE 10
Oxidation to Form Aldehyde (13).
To a solution of the above alcohol from debenzylation of 12 (2.84 g, 7 mmol) in CH2Cl2 (30 mL) was added Dess-Martin reagent (3.57 g, 8.4 mmol) at 23° C. After stirring for 1 h at 23° C., the reaction mixture was quenched with aq NaHCO3—Na2S2O3 (1:1, 50 mL) and extracted with ethyl acetate (3×50 mL). The organic phase was dried and concentrated in vacuo to afford the crude aldehyde. The crude product was purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:5) to give pure aldehyde 13 (2.68 g, 95%). Rf=0.56 (50% ethyl acetate in hexanes).
mp, 54–56° C.; [α]23 D−16.5 (c 0.60, CHCl3); FTIR (film) νmax: 3015, 2925, 1702 1297, 1247, 1170, 1096, 987, 794 cm−1; 1H NMR (CDCl3, 500 MHz): δ 9.62 (1H, s), 7.07 (2H, d, J=8.0 Hz), 6.73 (2H, d, J=8.5 Hz), 4.49 (1H, quart, J=8.5 Hz), 3.70 (3H, s), 3.67 (3H, s), 2.36 (2H, m), 1.75 (1H, m), 1.37 (3H, s), 0.73 (1H, m), 0.48 (1H, m), 0.07 (3H, s), 0.004 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 197.26, 174.70, 167.36, 158.07, 130.49, 128.96, 113.81, 83.97, 82.36, 55.34, 52.43, 47.74, 46.32, 23.83, 16.90, 7.52, 0.56, 0.45; HRMS (ESD calcd. for C20H28NO6Si (M+H)+ 406.1686, found 406.1692.
EXAMPLE 11
Figure US07183417-20070227-C00024
Conversion of (13) to (14).
To a solution of freshly prepared cyclohexenyl zinc chloride (10 mL, 0.5 M solution in THF, 5 mmol) (see Example 15 below) at −78° C. under nitrogen was added a −78° C. solution of aldehyde 13 (1.01 g, in 3 ml of THF, 2.5 mmol). After stirring for 5 h at −78° C. reaction mixture was quenched with water (10 mL) then extracted with ethyl acetate (3×10 mL). The combined organic layers were dried over Na2SO4 and solvent was removed in vacuo to give crude product (20:1 dr). The diastereomers were purified by column chromatography (silica gel, ethyl acetate/hexanes, 1:10 to 1:2 affords the pure major diastereomer 14 (1.0 g, 83%) and a minor diastereomer (50 mg 5%). For 14: Rf=0.56 (50% ethyl acetate in hexanes).
mp, 79–81° C.; [a]23 D−28.5 (c 1.45, CHCl3); FTIR (film) νmax: 3267, 2927, 2894, 2829, 1742, 1667, 1509, 1248, 1164, 1024, 795 cm−1; 1H NMR (CDCl3, 500 MHz): δ 7.34 (2H, d, J=8.5 Hz), 6.81 (2H, d, J=9.0 Hz), 5.84 (1H, m), 5.73 (1H, m), 4.88 (1H, d, J=15.5 Hz), 4.39 (1H, d, J=14.5 Hz), 4.11 (1H, t, J=6.5 Hz), 3.77 (3H, s), 3.58 (3H, s), 3.00 (1H, m), 2.95 (1H, d, J=9.0 Hz), 2.83 (1H, t, J=3.5 Hz), 3.36 (1H, m), 2.27 (1H, m), 1.98 (2H, m), 1.74 (3H, m), 1.62 (3H, s), 1.14 (2H, m), 0.59 (1H, m), 0.39 (11H, m), 0.13 (3H, s), 0.03 (3H, s); 13C NMR (CDCl3, 125 MHz): δ 176.80, 170.03, 158.27, 131.86, 131.34, 128.50, 126.15, 113.40, 83.96, 82.45, 77.17, 55.45, 51.46, 48.34, 48.29, 39.08, 28.34, 25.29, 22.45, 21.09, 17.30, 7.75, 0.39, 0.28; HRMS (ESI) calcd. for C26H38NO6Si (M+H)+ 488.2468, found 488.2477.
EXAMPLE 12
Figure US07183417-20070227-C00025
Tamao-Fleming Oxidation of (14) to (15).
To a solution of 14 (0.974 g, 2 mmol) in THF (5 mL) and MeOH (5 mL) at 23° C. was added KHCO3 (0.8 g, 8 mmol) and KF (0.348 g, 6 mmol). Hydrogen peroxide (30% in water, 5 mL) was then introduced to this mixture. The reaction mixture was vigorously stirred at 23° C. and additional hydrogen peroxide (2 ml) was added after 12 h. After 18 h, the reaction mixture was quenched carefully with NaHSO3 solution (15 mL). The mixture was extracted with ethyl acetate (3×25 mL) and the combined organic layers were washed with water and dried over Na2SO4. The solvent was removed in vacuo to give the crude product. The crude product was purified by column chromatography (silica gel, ethyl acetate) to give the pure triol 15 (0.82 g, 92%).
Rf=0.15 (in ethyl acetate). mp, 83–84° C.; [α]23 D: +5.2 (c 0.60, CHCl3); FTIR (film) νmax; 3317, 2920, 2827, 1741, 1654, 1502, 1246, 1170, 1018, 802 cm−1; 1HNMR(CDCl3, 500 MHz): δ 7.77 (2H, d, J=8.0 Hz), 6.28 (2H, d, J=8.0 Hz), 5. 76 (1H, m), 5.63 (1H, d, J=10.0 Hz), 4.74 (1H, d, J=15.5 Hz), 4.54 (1H, d, J=15.0 Hz), 4.12 (1H, d, J=2.5 Hz), 3.80 (1H, m), 3.76 (3H, s), 3.72 (1H, m), 3.68 (3H, s), 3.00 (1H, m), 2.60 (1H, br), 2.20 (1H, m), 1.98 (2H, s), 1.87 (1H, m), 1.80 (1H, m), 1.71 (2H, m), 1.61 (3H, s), 1.14 (2H, m); 13C NMR (CDCl3, 125 MHz): δ 178.99, 170.12, 158.27, 131.30, 130.55, 128.13, 126.39, 113.74, 81.93, 80.75, 76.87, 61.61, 55.45, 51.97, 51.32, 48.07, 39.17, 27.71, 27.13, 25.22, 21.35, 21.22; HRMS (ESI) calcd. for C24H34NO7 (M+H)+ 448.2335, found 448.2334.
EXAMPLE 13
Figure US07183417-20070227-C00026
Deprotection of (15) to (16).
To a solution of 15 (0.670 g, 1.5 mmol) in acetonitrile (8 mL) at 0° C. was added a pre-cooled solution of ceric ammonium nitrate (CAN) (2.46 g 4.5 mmol in 2 mL H2O). After stirring for 1 h at 0° C. the reaction mixture was diluted with ethyl acetate (50 mL), washed with saturated NaCl solution (5 mL) and organic layers was dried over Na2SO4. The solvent was removed in vacuo to give the crude product which was purified by column chromatography (silica gel, ethyl acetate) to give the pure 16 (0.4 g, 83%).
Rf=0.10 (5% MeOH in ethyl acetate). mp, 138 to 140° C.; [α]23 D+14.5 (c 1.05, CHCl3); FTIR (film) νmax 3301, 2949, 2911, 2850, 1723, 1673, 1437, 1371, 1239, 1156, 1008, 689 cm−1; 1H NMR (CDCl3, 600 MHz): δ 8.48 (1H, br), 6.08 (1H, m), 5. 75 (1H, d, J=9.6 Hz), 5.29 (1H, br), 4.13 (1H, d, J=6.6 Hz), 3.83 (3H, m), 3.79 (1H, m), 3.72 (1H, m), 2.84 (1H, d, J=10.2 Hz), 2.20 (1H, m), 2.16 (1H, br), 1.98 (3H, m), 1.77 (3H, m), 1.59 (1H, m), 1.54 (3H, s), 1.25 (1H, m). 13C NMR (CDCl3, 125 MHz): δ 180.84, 172.95, 135.27, 123.75, 82.00, 80.11, 75.56, 62.39, 53.14, 51.78, 38.95, 28.79, 26.48, 25.04, 20.66, 19.99; HRMS (ESI) calcd. (M+H)+ for C16H26NO6 328.1760, found 328.1752.
EXAMPLE 14
Figure US07183417-20070227-C00027
Conversion of (16) to Salinosporamide A(1).
A solution of triol ester 16 (0.164 g, 0.5 mmol) in 3 N aq LiOH (3 mL) and THF (1 mL) was stirred at 5° C. for 4 days until hydrolysis was complete. The acid reaction mixture was acidified with phosphoric acid (to pH 3.5). The solvent was removed in vacuo and the residue was extracted with EtOAc, separated, and concentrated in vacuo to give the crude trihydroxy carboxylic acid 16a (not shown). The crude acid was suspended in dry CH2Cl2 (2 mL), treated with pyridine (0.5 mL) and stirred vigorously at 23° C. for 5 min. To this solution was added BOPCl (152 mg, 0.6 mmol) at 23° C. under argon, and stirring was continued for 1 h. The solvent was removed under high vacuum and the residue was suspended in dry CH3CN (1 mL) and treated with pyridine (1 mL). To this solution was added PPh3Cl2 (333 mg, 1.0 mmol) at 23° C. under argon with stirring. After 1 h the solvent was removed in vacuo. The crude product was purified by column chromatography (silica gel, ethyl acetate-CH2Cl2, 1:5) to give the pure β-lactone 1 (100 mg, 64%) as a colorless solid.
Rf=0.55 (50% ethyl acetate in hexane). mp, 168–170° C. (authentic sample: 168–170° C., 169–171° C. in Angew. Chem. Int. Ed., 2003, 42, 355–357); mixture mp, 168–170C. [α]23 D −73.2 (c 0.49, MeOH), −72.9 (c 0.55, MeOH, in Angew. Chem. Int. Ed., 2003, 42, 355–357); FTIR (film) νmax: 3406, 2955, 2920, 2844, 1823, 1701, 1257, 1076, 1012, 785, 691 cm−1; 1H NMR (CDCl3, 500 MHz): δ 10.62 (1H, br), 6.42 (1H, d, J=10.5 Hz), 5.88 (1H, m), 4.25 (1H, d, J=9.0 Hz), 4.14 (1H, m), 4.01 (1H, m), 3.17 (1H, t, J=7.0 Hz), 2.85 (1H, m), 2.48 (1H, m), 2.32 (2H, m), 2.07 (3H, s), 1.91 (2H, m), 1.66 (2H, m), 1.38 (1H, m);13C NMR (CDCl3, 125 MHz): δ 176.92, 169.43, 129.08, 128.69, 86.32, 80.35, 70.98, 46.18, 43.28, 39.31, 29.01, 26.47, 25.35, 21.73, 20.00; HRMS (ESI) calcd. for (M−H)− C15H19ClNO4 312.1003, found 312.1003.


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Name:Marizomib
Synonyms:6-Oxa-2-azabicyclo[3.2.0]heptane-3,7-dione, 4-(2-chloroethyl)-1-[(S)-(1S)-2-cyclohexen-1-ylhydroxymethyl]-5-methyl-, (1R,4R,5S)-;  Other Names: (-)-Salinosporamide A; ML 858; Marizomib; NPI 0052; Salinosporamide A
CAS Registry Number:437742-34-2 
Molecular Formula:C15H20ClNO4
Molecular Weight:313.1
Molecular Structure: 
...................


3  CARFILZOMIB

Carfilzomib

Amgen’s Multiple Myeloma Drug Shows Promise in Phase 3 Trial

The drug maker is seeing great signs in the development of treatment for multiple myeloma, a bone marrow cancer. The results from its Phase 3 of Kyprolis’ clinical trial shows that patients can live almost nine months longer without worsening symptoms. According to Amgen, about 70,000 people in the U.S. are living with the disease and 24,000 new cases are diagnosed every year. With the good clinical trial result, Amgen plans to begin regulatory submissions around the world next year. Dr. Pablo Cagnoni, president of Amgen’s subsidiary Onyx Pharmaceuticals said, “The results demonstrate that Kyprolis can significantly extend the time patients live without their disease progressing. The ability of novel therapies to produce deep and durable responses may, one day, transform this uniformly fatal disease to one that is chronic and manageable.” Male patients over the age of 65 have the highest risk of developing it.
Carfilzomib (marketed under the trade name Kyprolis, Onyx Pharmaceuticals, Inc.) is an anti-cancer drug acting as a selectiveproteasome inhibitor. Chemically, it is a tetrapeptide epoxyketone and an analog of epoxomicin.[1]
The U.S. Food and Drug Administration (FDA) approved it on 20 July 2012 for use in patients with multiple myeloma who have received at least two prior therapies, including treatment with bortezomib and an immunomodulatory therapy and have demonstrated disease progression on or within 60 days of completion of the last therapy. Approval is based on response rate. Clinical benefit, such as improvement in survival or symptoms, has not been verified.[2]
The abbreviation CFZ is common for referring to carfilzomib, but abbreviating drug names is not best practice in medicine.

Discovery, early development and regulatory approval

Carfilzomib is derived from epoxomicin, a natural product that was shown by the laboratory of Craig Crews at Yale University to inhibit the proteasome.[3] The Crews laboratory subsequently invented a more specific derivative of epoxomicin named YU101,[4] which was licensed to Proteolix, Inc. Craig Crews, Raymond Deshaies from Caltech, Phil Whitcome, the former CEO of Neurogen and Larry Lasky, a venture capitalist, founded Proteolix, and along with other researchers and scientists, advanced YU101. The scientists at Proteolix invented a new, distinct compound that had potential use as a drug in humans, known as carfilzomib. Proteolix advanced carfilzomib to multiple Phase 1 and 2 clinical trials, including a pivotal Phase 2 clinical trial designed to seek accelerated approval.[5]Clinical trials for carfilzomib continue under Onyx Pharmaceuticals, which acquired Proteolix in 2009.[5]
In January 2011, the FDA granted carfilzomib fast-track status, allowing Onyx to initiate a rolling submission of its new drug application for carfilzomib.[6] In December 2011, the FDA granted Onyx standard review designation,[7][8] for its new drug application submission based on the 003-A1 study, an open-label, single-arm Phase 2b trial. The trial evaluated 266 heavily-pretreated patients with relapsed and refractory multiple myeloma who had received at least two prior therapies, including bortezomib and either thalidomide orlenalidomide.[9] It costs approximately $10,000 per 28-day cycle, making it the most expensive FDA-approved drug for multiple myeloma.[10]

Mechanism

Carfilzomib irreversibly binds to and inhibits the chymotrypsin-like activity of the 20S proteasome, an enzyme that degrades unwanted cellular proteins. Inhibition of proteasome-mediated proteolysis results in a build-up of polyubiquinated proteins, which may cause cell cycle arrest, apoptosis, and inhibition of tumor growth.[1]

Clinical trials

Completed

A single-arm, Phase II trial (003-A1) of carfilzomib in patients with relapsed and refractory multiple myeloma showed that single-agent carfilzomib demonstrated a clinical benefit rate of 36 percent in the 266 patients evaluated and had an overall response rate of 22.9 percent and median duration of response of 7.8 months. The FDA approval of carfilzomib was based on results of the 003-A1 trial.[11]
In a Phase II trial (004), carfilzomib had a 53 percent overall response rate among patients with relapsed and/or refractory multiple myeloma who had not previously received bortezomib. This study also included a bortezomib-treated cohort. Results were reported separately.[12] This study also found prolonged carfilzomib treatment was tolerable, with approximately 22 percent of patients continuing treatment beyond one year. The 004 trial was a smaller study originally designed to investigate the impact of carfilzomib treatment in relationship to bortezomib treatment in less heavily pretreated (1-3 prior regimens) patients.[13]
A Phase II trial (005), which assessed the safety, pharmacokinetics, pharmacodynamics and efficacy of carfilzomib, in patients with multiple myeloma and varyi ng degrees of renal impairment, where nearly 50 percent of patients were refractory to both bortezomib and lenalidomide, demonstrated that pharmacokinetics and safety were not influenced by the degree of baseline renal impairment. Carfilzomib was tolerable and demonstrated efficacy.[14]
In another Phase II trial (006) of patients with relapsed and/or refractory multiple myeloma, carfilzomib in combination with lenalidomide and dexamethasone demonstrated an overall response rate of 69 percent.[15]
A Phase II trial (007) for multiple myeloma and solid tumors showed promising results.[16][17]
In Phase II trials of carfilzomib, the most common grade 3 or higher treatment-emergent adverse events were thrombocytopenia, anemia, lymphoenia, neutropenia, pneumonia, fatigue and hyponatremia.[18]
In a frontline Phase I/II study, the combination of carfilzomib, lenalidomide, and low-dose dexamethasone was highly active and well tolerated, permitting the use of full doses for an extended time in newly-diagnosed multiple myeloma patients, with limited need for dose modification. Responses were rapid and improved over time, reaching 100 percent very good partial response.[19]

Ongoing

A phase III confirmatory clinical trial, known as the ASPIRE trial, comparing carfilzomib, lenalidomide and dexamethasone versus lenalidomide and dexamethasone in patients with relapsed multiple myeloma is ongoing.[20] It is no longer recruiting and should report in 2014.

SYSTEMATIC (IUPAC) NAME
(S)-4-Methyl-N-((S)-1-(((S)-4-methyl-1-((R)-2-methyloxiran-2-yl)-1-oxopentan-2-yl)amino)-1-oxo-3-phenylpropan-2-yl)-2-((S)-2-(2-morpholinoacetamido)-4-phenylbutanamido)pentanamide
CLINICAL DATA
TRADE NAMESKyprolis
LICENCE DATAUS FDA:link
PREGNANCY CAT.D (US)
LEGAL STATUS℞-only (US)
ROUTESIntravenous
IDENTIFIERS
CAS NUMBER868540-17-4
ATC CODEL01XX45
PUBCHEMCID 11556711
CHEMSPIDER9731489
KEGGD08880
CHEMBLCHEMBL451887
SYNONYMSPX-171-007
CHEMICAL DATA
FORMULAC40H57N5O7 
MOL. MASS719.91 g mol

 


 

 

The initial enthusiasm following the discovery of a pharmacologically active natural product is often fleeting due to the poor prospects for its ultimate clinical application. Despite this, the ever-changing landscape of modern biology has a constant need for molecular probes that can aid in our understanding of biological processes. After its initial discovery by Bristol-Myers Squibb as a microbial anti-tumor natural product, epoxomicin was deemed unfit for development due to its peptide structure and potentially labile epoxyketone pharmacophore. Despite its drawbacks, epoxomicin’s pharmacophore was found to provide unprecedented selectivity for the proteasome. Epoxomicin also served as a scaffold for the generation of a synthetic tetrapeptide epoxyketone with improved activity, YU-101, which became the parent lead compound of carfilzomib (Kyprolis™), the recently approved therapeutic agent for multiple myeloma. In this era of rational drug design and high-throughput screening, the prospects for turning an active natural product into an approved therapy are often slim. However, by understanding the journey that began with the discovery of epoxomicin and ended with the successful use of carfilzomib in the clinic, we may find new insights into the keys for success in natural product-based drug discovery.

Graphical abstract: From epoxomicin to carfilzomib: chemistry, biology, and medical outcomes

References

  1.  Carfilzomib, NCI Drug Dictionary
  2. “FDA Approves Kyprolis for Some Patients with Multiple Myeloma”. FDA. 2012-07-20. Retrieved 2013-07-23.
  3. Meng, L; Mohan, R.; Kwok, B.H.; Elofsson, M.; Sin, N.; Crews, C.M. (1999).“Epoxomicin, a potent and selective proteasome inhibitor, exhibits in vivo antiinflammatory activity”. Proc Natl Acad Sci USA 96 (18): 10403–8.doi:10.1073/pnas.96.18.10403.PMC 17900. PMID 10468620.
  4.  Myung, J; Kim, K.B.; Lindsten, K.; Dantuma, N.P.; Crews, C.M. (2001). “Lack of proteasome active site allostery as revealed by subunit-specific inhibitors”. Mol Cell 7 (2): 411–20. doi:10.1016/S1097-2765(01)00188-5. PMID 11239469.
  5. ^ Jump up to:a b “Carfilzomib: From Discovery To Drug”. Chemical & Engineering News. 2012-08-27. Retrieved 2013-07-30.
  6. “Onyx multiple myeloma drug wins FDA fast-track status”. San Francisco Business Times. 2011-01-31. Retrieved 2011-09-01.
  7.  “Beacon Breaking News – Carfilzomib to Get Standard, Not Priority, FDA Review”. The Myeloma Beacon. Retrieved 2012-02-27.
  8.  “Fast Track, Accelerated Approval and Priority Review; Accelerating Availability of New Drugs for Patients with Serious Diseases”. FDA. Retrieved 2012-02-27.
  9.  “PX-171-003-A1, an open-label, single-arm, phase (Ph) II study of carfilzomib (CFZ) in patients (pts) with relapsed and refractory multiple myeloma (R/R MM): Long-term follow-up and subgroup analysis”. ASCO 2011; Abstract 8027. 2011. Retrieved 2011-09-01.
  10.  “FDA Approves Kyprolis (Carfilzomib) For Relapsed And Refractory Multiple Myeloma”. The Myeloma Beacon. Retrieved 2012-07-20.
  11.  “Carfilzomib Prescribing Information”. NCI Drug Dictionary. Retrieved 2013-07-23.
  12.  Vij, R (2012). “An open-label, single-arm, phase 2 study of single-agent carfilzomib in patients with relapsed and/or refractory multiple myeloma who have been previously treated with bortezomib”. Br J Haematol 158 (6): 739–748. doi:10.1111/j.1365-2141.2012.09232.x. PMID 22845873.
  13.  Vij, R (2012). “An open-label, single-arm, phase ii (PX-171-004) study of single-agent carfilzomib in bortezomib-naive patients with relapsed and/or refractory multiple myeloma.”. Blood 119 (24): 5661–70. doi:10.1182/blood-2012-03-414359.PMID 22555973.
  14.  Badros, AZ (2013). “Carfilzomib in multiple myeloma patients with renal impairment: pharmacokinetics and safety.”. Leukemia27 (8): 1707–14. doi:10.1038/leu.2013.29.PMID 23364621.
  15. “European Hematology Association (EHA) 18th Congress. June 13-16, 2013.”. The Myeloma Beacon. 2013. Retrieved 2013-07-13.
  16.  “Nikoletta Lendval, MD PhD et al. Phase II Study of Infusional Carfilzomib in Patients with Relapsed or Refractory Multiple Myeloma.”. Presented at: 54th ASH Annual Meeting and Exposition: December 2012. Retrieved 2013-07-23.
  17.  “Phase II results of Study PX-171-007: A phase Ib/II study of carfilzomib (CFZ), a selective proteasome inhibitor, in patients with selected advanced metastatic solid tumors” – ASCO 2009; Abstract 3515.
  18.  “Siegel DS, Martin T, Wang, M, et al. Results of PX-171- 003-A1, an open-label, single-arm, phase 2 study of carfilzomib in patients with relapsed and refractory multiple myeloma. Presented at: 52nd ASH Annual Meeting and Exposition; December 4-7, 2010; Orlando, Florida.”. OncLive.com. 2011-03-09. Retrieved 2011-09-01.
  19.  “Final Results of a Frontline Phase 1/2 Study of Carfilzomib Lenalidomide, and Low-Dose Dexamethasone (CRd) in Multiple Myeloma (MM)”. ASH 20111; Abstract 631. Retrieved 2012-02-27.
  20.  “Phase 3 Study Comparing Carfilzomib, Lenalidomide, and Dexamethasone (CRd) Versus Lenalidomide and Dexamethasone (Rd) in Subjects With Relapsed Multiple Myeloma”. ClinicalTrials.gov. 2011-08-04. Retrieved 2011-09-01.

External links

 

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