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Ecallantide (Kalbitor) is a potent and highly specific plasma kallikrein inhibitor used for treating hereditary angioedema (HAE), or to treat acute attack of a certain immune disease passed down through families (hereditary angioedema-HAE). It poses no risk of viral contamination, is highly selective, has a quick onset of action and can be administered subcutaneously. In clinical trials, ecallantide appears to be a safe and effective drug useful for the treatment of HAE patients suffering from an acute attack. Ecallantide was found to be superior compared with placebo in relieving symptoms, decreasing the severity of attacks and shortening the duration of attacks. The primary safety concern appears to be related to hypersensitivity reactions. Phase IV postmarketing surveillance studies to monitor the incidence of these reactions will be implemented by the company now that the drug has been US FDA approved.
Physicochemical Properties
| Molecular Formula | C305H442N88O91S8 |
| Molecular Weight | 7053.82803583145 |
| Exact Mass | 7052.053 |
| CAS # | 460738-38-9 |
| Related CAS # | Ecallantide TFA |
| PubChem CID | 156024995 |
| Sequence | EAMHSFCAFKADDGPCRAAHPRWFFNIFXRQCEEFIYGGCEGNQNRFESLEECKKMCXRD |
| Appearance | Typically exists as solid at room temperature |
| LogP | -27.9 |
| Hydrogen Bond Donor Count | 100 |
| Hydrogen Bond Acceptor Count | 110 |
| Rotatable Bond Count | 133 |
| Heavy Atom Count | 492 |
| Complexity | 18500 |
| Defined Atom Stereocenter Count | 60 |
| SMILES | CC[C@@H](C)[C@H]1C(=O)N[C@@H](C(=O)NCC(=O)NCC(=O)N[C@H]2CSSC[C@H]3C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N4CCC[C@@H]4C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@H](C(=O)N[C@@H](C(=O)N[C@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](CSSC[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)N[C@@H](CSSC[C@@H](C(=O)N[C@@H](C(=O)N[C@H](C(=O)N[C@@H](C(=O)N[C@H](C(=O)N[C@@H](C(=O)N[C@@H](C(=O)NCC(=O)N5CCC[C@@H]5C(=O)N3)CC(=O)O)CC(=O)O)C)CCCCN)CC6=CC=CC=C6)C)NC(=O)[C@H](CC7=CC=CC=C7)NC(=O)[C@@H](CO)NC(=O)[C@@H](CC8=CN=CN8)NC(=O)[C@H](CCSC)NC(=O)[C@H](C)NC(=O)[C@H](CCC(=O)O)N)C(=O)N[C@@H]([C@H](C)O)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@H](CC(=O)O)C(=O)O)CCSC)CCCCN)CCCCN)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](NC(=O)CNC(=O)[C@H](NC2=O)CCC(=O)O)CC(=O)N)CCC(=O)N)CC(=O)N)CCCNC(=N)N)CC9=CC=CC=C9)CCC(=O)O)CO)CC(C)C)CCC(=O)O)CCC(=O)O)C(=O)N[C@H](C(=O)N[C@H](C(=O)N[C@H](C(=O)N1)CC1=CC=CC=C1)CCC(=O)O)CCC(=O)O)CCC(=O)N)CCCNC(=N)N)[C@@H](C)O)CC1=CC=CC=C1)[C@H](C)CC)CC(=O)N)CC1=CC=CC=C1)CC1=CC=CC=C1)CC1=CNC2=CC=CC=C21)CCCNC(=N)N)CC1=CN=CN1)C)C)CCCNC(=N)N)CC1=CC=C(C=C1)O |
| InChi Key | VBGWSQKGUZHFPS-BRUBJIIKSA-N |
| InChi Code | InChI=1S/C305H442N88O91S8/c1-16-152(5)241-295(478)377-195(124-168-80-82-172(398)83-81-168)252(435)334-137-227(404)333-138-228(405)345-214-143-487-491-147-218-291(474)351-179(73-47-107-327-301(315)316)255(438)341-154(7)245(428)339-155(8)249(432)379-210(127-171-136-326-150-338-171)299(482)393-113-53-79-221(393)294(477)361-181(75-49-109-329-303(319)320)260(443)372-203(125-169-134-332-175-69-40-39-68-173(169)175)277(460)370-198(119-163-58-29-20-30-59-163)274(457)369-199(120-164-60-31-21-32-61-164)275(458)375-207(130-226(314)403)284(467)389-242(153(6)17-2)296(479)378-202(123-167-66-37-24-38-67-167)283(466)390-243(159(12)396)297(480)362-182(76-50-110-330-304(321)322)258(441)353-186(86-94-223(311)400)267(450)383-217(290(473)359-188(89-98-234(414)415)263(446)354-189(90-99-235(416)417)265(448)368-201(282(465)388-241)122-166-64-35-23-36-65-166)146-490-489-145-216(384-268(451)191(92-101-237(420)421)355-262(445)187(88-97-233(412)413)357-271(454)194(116-151(3)4)366-285(468)212(141-394)381-266(449)190(91-100-236(418)419)358-273(456)197(118-162-56-27-19-28-57-162)367-259(442)180(74-48-108-328-302(317)318)349-280(463)206(129-225(313)402)374-264(447)185(85-93-222(310)399)356-279(462)205(128-224(312)401)344-229(406)139-335-251(434)184(352-288(214)471)87-96-232(410)411)289(472)350-178(72-43-46-106-308)256(439)347-177(71-42-45-105-307)257(440)360-193(103-115-486-15)270(453)385-219(292(475)391-244(160(13)397)298(481)363-183(77-51-111-331-305(323)324)261(444)380-211(300(483)484)133-240(426)427)148-492-488-144-215(386-276(459)200(121-165-62-33-22-34-63-165)371-286(469)213(142-395)382-278(461)204(126-170-135-325-149-337-170)373-269(452)192(102-114-485-14)346-246(429)156(9)340-250(433)174(309)84-95-231(408)409)287(470)343-158(11)247(430)364-196(117-161-54-25-18-26-55-161)272(455)348-176(70-41-44-104-306)254(437)342-157(10)248(431)365-209(132-239(424)425)281(464)376-208(131-238(422)423)253(436)336-140-230(407)392-112-52-78-220(392)293(476)387-218/h18-40,54-69,80-83,134-136,149-160,174,176-221,241-244,332,394-398H,16-17,41-53,70-79,84-133,137-148,306-309H2,1-15H3,(H2,310,399)(H2,311,400)(H2,312,401)(H2,313,402)(H2,314,403)(H,325,337)(H,326,338)(H,333,404)(H,334,435)(H,335,434)(H,336,436)(H,339,428)(H,340,433)(H,341,438)(H,342,437)(H,343,470)(H,344,406)(H,345,405)(H,346,429)(H,347,439)(H,348,455)(H,349,463)(H,350,472)(H,351,474)(H,352,471)(H,353,441)(H,354,446)(H,355,445)(H,356,462)(H,357,454)(H,358,456)(H,359,473)(H,360,440)(H,361,477)(H,362,480)(H,363,481)(H,364,430)(H,365,431)(H,366,468)(H,367,442)(H,368,448)(H,369,457)(H,370,460)(H,371,469)(H,372,443)(H,373,452)(H,374,447)(H,375,458)(H,376,464)(H,377,478)(H,378,479)(H,379,432)(H,380,444)(H,381,449)(H,382,461)(H,383,450)(H,384,451)(H,385,453)(H,386,459)(H,387,476)(H,388,465)(H,389,467)(H,390,466)(H,391,475)(H,408,409)(H,410,411)(H,412,413)(H,414,415)(H,416,417)(H,418,419)(H,420,421)(H,422,423)(H,424,425)(H,426,427)(H,483,484)(H4,315,316,327)(H4,317,318,328)(H4,319,320,329)(H4,321,322,330)(H4,323,324,331)/t152-,153-,154-,155-,156+,157+,158-,159-,160+,174+,176-,177-,178-,179-,180+,181-,182-,183+,184-,185+,186-,187+,188+,189+,190+,191+,192+,193-,194+,195-,196+,197+,198-,199-,200+,201+,202+,203-,204-,205-,206+,207+,208-,209-,210-,211-,212+,213-,214+,215+,216+,217+,218+,219+,220-,221-,241+,242-,243-,244+/m1/s1 |
| Chemical Name | (2R)-2-[[(2S)-2-[[(2S,3S)-2-[[(1R,2aS,4R,5aS,8aS,11aR,13R,14aR,16R,17aR,19S,20aR,22R,23aS,25S,26aR,28R,29aS,31R,32aR,35aR,36R,38aR,39R,41aR,42R,44aR,45R,48R,50aR,51S,53aR,54S,56aR,57S,59aR,60S,63S,66S,69S,72S,75S,78R,84R,87R,96R,99S)-22,42,45-tris(4-aminobutyl)-31-[[(2S)-2-[[(2R)-2-[[(2R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-amino-4-carboxybutanoyl]amino]propanoyl]amino]-4-methylsulfanylbutanoyl]amino]-3-(1H-imidazol-5-yl)propanoyl]amino]-3-hydroxypropanoyl]amino]-3-phenylpropanoyl]amino]-29a,72,78-tris(2-amino-2-oxoethyl)-14a,75-bis(3-amino-3-oxopropyl)-2a,23a,25,32a,35a,66-hexabenzyl-26a,99-bis[(2R)-butan-2-yl]-17a,41a,59a,69-tetrakis(3-carbamimidamidopropyl)-5a,8a,51,54,63,84-hexakis(2-carboxyethyl)-13,16-bis(carboxymethyl)-20a-[(1R)-1-hydroxyethyl]-60-(hydroxymethyl)-96-[(4-hydroxyphenyl)methyl]-50a-(1H-imidazol-5-ylmethyl)-38a-(1H-indol-3-ylmethyl)-19,28,53a,56a-tetramethyl-57-(2-methylpropyl)-39-(2-methylsulfanylethyl)-1a,3,4a,7a,9,10a,12,13a,15,16a,18,19a,21,22a,24,25a,27,28a,30,31a,34a,37a,38,40a,41,43a,44,47,49a,50,52a,53,55a,56,58a,59,61a,62,65,68,71,74,77,80,83,86,89,92,95,98-pentacontaoxo-33,34,63a,64a,67a,68a-hexathia-a,2,3a,6a,8,9a,11,12a,14,15a,17,18a,20,21a,23,24a,26,27a,29,30a,33a,36a,37,39a,40,42a,43,46,48a,49,51a,52,54a,55,57a,58,60a,61,64,67,70,73,76,79,82,85,88,91,94,97-pentacontazapentacyclo[85.74.4.448,111.04,8.0144,148]nonahexacontahectane-36-carbonyl]amino]-3-hydroxybutanoyl]amino]-5-carbamimidamidopentanoyl]amino]butanedioic acid |
| HS Tariff Code | 2934.99.9001 |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| ADME/Pharmacokinetics |
Absorption, Distribution and Excretion In a pharmacokinetic study in healthy individuals, peak plasma concentrations of ecallantide were achieved at approximately 2-3 hours following a 30 mg dose of ecallantide administered by subcutaneous injection; an approximate bioavailability of 90% was reported with subcutaneous administration. Ecallantide is eliminated in urine; however, since the drug is a small protein, metabolic catabolism (or degradation) is also a likely elimination process. It is not known whether ecallantide is excreted in human milk. Biological Half-Life The mean half life of ecallantide is 2 hours. |
| Toxicity/Toxicokinetics |
Toxicity Summary IDENTIFICATION AND USE: Ecallantide, a biosynthetic protein based on the first Kunitz domain of human tissue factor pathway inhibitor, is a reversible and selective inhibitor of plasma kallikrein. Ecallantide is a clear, colorless solution. Ecallantide is indicated for treatment of acute attacks of hereditary angioedema (HAE) in patients 12 years of age and older. HUMAN EXPOSURE AND TOXICITY: There have been no reports of overdose with ecallantide. HAE patients have received single doses up to 90 mg intravenously without evidence of dose-related toxicity. Potentially serious hypersensitivity reactions, including anaphylaxis, have occurred in patients treated with ecallantide. In 255 hereditary angioedema (HAE) patients treated with intravenous or subcutaneous ecallantide in clinical studies, 10 patients (4%) experienced anaphylaxis. For the subgroup of 187 patients treated with subcutaneous ecallantide, 5 patients (3%) experienced anaphylaxis. Symptoms associated with these reactions have included chest discomfort, flushing, pharyngeal edema, pruritus, rhinorrhea, sneezing, nasal congestion, throat irritation, urticaria, wheezing, and hypotension. These reactions occurred within the first hour after dosing. Other adverse reactions indicative of hypersensitivity reactions included the following: pruritus (5%), rash (3%), and urticaria (2%). ANIMAL STUDIES: A two-year study was conducted in rats to assess the carcinogenic potential of ecallantide. No evidence of tumorigenicity was observed in rats at doses up to 10 mg/kg administered subcutaneously every three days (approximately 2-fold greater than the maximum recommended human dose (MRHD) on an AUC basis). In rats, intravenous ecallantide at a dose approximately 13 times the maximum recommended human dose (MRHD) (on a mg/kg basis at a maternal dose of 15 mg/kg/day in rats) caused increased numbers of early resorptions and percentages of resorbed conceptuses per litter in the presence of mild maternal toxicity. No development toxicity was observed in rats that received an intravenous dose approximately 8 times the MRHD (at a maternal dose of 10 mg/kg/day in rats). There were no adverse effects of ecallantide on embryofetal development in rats that received subcutaneous doses up to approximately 2.4 times the MRHD (at a maternal dose of 20 mg/kg/day in rats), and in rabbits that received intravenous doses up to approximately 6 times the MRHD (at a maternal dose of 5 mg/kg/day in rabbits). Ecallantide had no effects on fertility and reproductive performance in rats at subcutaneous doses up to 25 mg/kg/day (approximately 21 times MRDH). Effects During Pregnancy and Lactation ◉ Summary of Use during Lactation No information is available on the use of ecallantide during breastfeeding. Because ecallantide is a large protein molecule with a molecular weight of about 7,000 Da, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant's gastrointestinal tract. Until more data become available, ecallantide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. ◉ Effects in Breastfed Infants Relevant published information was not found as of the revision date. ◉ Effects on Lactation and Breastmilk Relevant published information was not found as of the revision date. |
| References | Expert Rev Clin Immunol . 2010 Jan;6(1):29-39. doi: 10.1586/eci.09.60. |
| Additional Infomation |
Mechanism of Action Ecallantide, a biosynthetic protein based on the first Kunitz domain of human tissue factor pathway inhibitor, is a reversible and selective inhibitor of plasma kallikrein. Therapeutic Uses Kalbitor (Ecallantide) is indicated for treatment of acute attacks of hereditary angioedema (HAE) in patients 12 years of age and older. /Included in US product label/ Drug Warnings /BOXED WARNING/ WARNING: ANAPHYLAXIS. Anaphylaxis has been reported after administration of Kalbitor. Because of the risk of anaphylaxis, Kalbitor should only be administered by a healthcare professional with appropriate medical support to manage anaphylaxis and hereditary angioedema. Healthcare professionals should be aware of the similarity of symptoms between hypersensitivity reactions and hereditary angioedema and patients should be monitored closely. Do not administer Kalbitor to patients with known clinical hypersensitivity to Kalbitor. Potentially serious hypersensitivity reactions, including anaphylaxis, have occurred in patients treated with Kalbitor. In 255 hereditary angioedema (HAE) patients treated with intravenous or subcutaneous Kalbitor in clinical studies, 10 patients (4%) experienced anaphylaxis. For the subgroup of 187 patients treated with subcutaneous Kalbitor, 5 patients (3%) experienced anaphylaxis. Symptoms associated with these reactions have included chest discomfort, flushing, pharyngeal edema, pruritus, rhinorrhea, sneezing, nasal congestion, throat irritation, urticaria, wheezing, and hypotension. These reactions occurred within the first hour after dosing. Other adverse reactions indicative of hypersensitivity reactions included the following: pruritus (5%), rash (3%), and urticaria (2%). Patients should be observed for an appropriate period of time after administration of Kalbitor, taking into account the time to onset of anaphylaxis seen in clinical trials. Given the similarity in hypersensitivity symptoms and acute HAE symptoms, patients should be monitored closely in the event of a hypersensitivity reaction. There are no adequate and well-controlled trials of Kalbitor in pregnant women. Kalbitor has been shown to cause developmental toxicity in rats, but not rabbits. Because animal reproductive studies are not always predictive of human response, Kalbitor should be used during pregnancy only if clearly needed. FDA Pregnancy Risk Category: C /RISK CANNOT BE RULED OUT. Adequate, well controlled human studies are lacking, and animal studies have shown risk to the fetus or are lacking as well. There is a chance of fetal harm if the drug is given during pregnancy; but the potential benefits may outweigh the potential risk./ For more Drug Warnings (Complete) data for Ecallantide (11 total), please visit the HSDB record page. |
Solubility Data
| Solubility (In Vitro) | May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples |
| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.1418 mL | 0.7088 mL | 1.4177 mL | |
| 5 mM | 0.0284 mL | 0.1418 mL | 0.2835 mL | |
| 10 mM | 0.0142 mL | 0.0709 mL | 0.1418 mL |