Status: recently approved in U.S.; long marketed in Europe

Organizations involved:

Baxter AG – Manuf.; R&D; Tech.; Intl. mark.

Baxter Hyland Immuno – USA mark.

Polymun Scientific Immunbiologische Forschung GmbH – Manuf. other

Cross ref.: See recombinant activated protein C (Xigris; #243). Note, Ceprotin does not compete with Xigris.

Description: Ceprotin is a lyophilized (freeze-dried) human Protein C product derived from human plasma. Purification includes immunoaffinity chromatography using matrix-immobililzed murine (mouse) Protein C-specific monoclonal antibodies. manufacture includes two viral inactivation steps – vapor heating (wet pasteurization) and detergent inactivation with polysorbate 80 (Tween-80).

Note, the Protein C in Ceprotin is not activated. Rather, it is activated in vivo, unlike the (pre)activated recombinant Protein C in Xigris.

Ceprotin is packaged in single-dose vials that contain nominally 500 (indicated by a blue color bar) or 1,000 (green color bar) International Units (IU) human Protein C, and is reconstituted with 5 mL and 10 mL of Sterile Water for Injection, respectively, to provide a single dose of human Protein C at a concentration of 100 IU/mL. The potency (IU) is determined using a chromogenic substrate method referenced against the World Health Organization (WHO) International Standard (86/622).

Ceprotin, when reconstituted with diluent, contains 8 mg/mL Albumin, human; 4.4 mg/mL trisodium citrate dihydrate; and 8.8 mg/mL sodium chloride. Actual potency is printed on the vial label. Ceprotin is supplied as a sterile, white or cream colored, lyophilized powder for IV injection. It has a pH between 6.7 and 7.3 and an osmolality not lower than 240 mosmol/kg. Ceprotin has as shelf-life of 3 years when stored at 2°C–8°C (36°-46°F; refrigerated). The date of manufacture, as defined by FDA, is the date of final sterile filtration of the formulated drug product. Following the final sterile filtration, no reprocessing/reworking is allowed without prior approval from FDA.

Ceprotin may contain traces of mouse protein and/or heparin as a result of the manufacturing process.

Nomenclature: Protein C, human [BIO]; Ceprotin [TR]; Protein C Concentrate (Human) [FDA]; NDC: 0944-4175-05; NDC: 0944-4175-10 [NDC]

Biological.: See the Protein C, rDNA (Xigris; #243).

Protein C is the precursor of a vitamin K-dependent anticoagulant glycoprotein (serine protease) that is produced in the liver. It is converted by the thrombin/thrombomodulin-complex on the endothelial cell surface to activated Protein C (APC). APC is a serine protease with potent anticoagulant effects, especially in the presence of its cofactor, protein S. APC exerts its effect by the inactivation of the activated forms of Factors V and VIII, which leads to a decrease in thrombin and clot formation. APC also has profibrinolytic effects. When infused, nonactivated protein C is converted or activated ‘on site’ and ‘on demand’ by the patient’s own body’s thrombomodulin to the active enzyme APC (Activated Protein C).

The activity of Protein C is measured in international units (IU). One IU of protein C corresponds to the amidolytically measured activity of Protein C in 1 mL fresh normal human plasma (based on the international WHO plasma standard for human protein C). Values from assays are calibrated against the WHO International Standard (86/622) (Hubbard AR). Protein C activity is either given in IU/mL where 1 IU/mL is normal or as a percentage of normal (1 IU/mL =100%). See “Standardization of protein C in plasma: establishment of an international standard,” Thromb Haemost 59(3):464-467;1988.

Companies.: Ceprotin, particularly for European use, but perhaps also for worldwide distribution, is manufactured by Baxter AG (Vienna, Austria). FDA reports it as manufactured (approval held by) Baxter International (Baxter Hyland Immuno; Glendale, CA), CBER/FDA est. no. 0140. However, the FDA approval letter redacts (censors) manufacturing location-related text. For such an ultra-orphan product, it seems unlikely that Baxter manufacture Ceprotin at multiple facilities.

Ceprotin is marketed in the U.S. by Baxter International (Baxter Hyland Immuno), and in the European Union and internationally by Baxter AG and Baxter affiliates.

Polymun Scientific Immunbiologische Forschung GmbH manufactures mouse monoclonal antibody HPC4 which is used for the affinity purification of Protein C for Ceprotin.

Manufacture: As described in U.S. patent 5,549,893 (see the Tech. transfer section below), crude Protein C fraction is obtained from prothrombin complex concentrate (see related entry). Purification includes affinity chromatography using a Protein C-specific monoclonal antibody (HPC4).

Originally, as described in this patent, the monoclonal anti-protein C antibodies used for purification were conventionally derived. BALB/C mice were immunized with 100 µg human protein C by intraperitoneal injection at two-week intervals. After six weeks, another 50 µg of human Protein C was injected and fusion with a human myeloma cell line was carried out three days later. The myeloma cell line (P3-X-63-AG8-653, 1.5.times.107 cells) was mixed with 1.7 x 108 mouse spleen cells and fused using PEG-1500 (polyethylene glycol with a median molecular weight if 1.5 kDa). Positive clones, assayed by means of ELISA, were subcloned twice. Ascites production (i.e., culture in vivo within the peritoneal cavity of mice) of the monoclonal antibody was effected by injection of 5 x 106 hybridoma cells per BALB/C mouse two weeks after pristane treatment. The immunoglobulin (monoclonal antibody) was purified from ascites by means of ammonia sulfate precipitation and subsequent chromatography on QAE-Sephadex (Pharmacia) and, further, by chromatography on Sephadex G200 (Pharmacia). To reduce the risk of transmission of murine viruses, the antibody was subjected to a further virus inactivation step (unspecified) prior to immobilization. The monoclonal protein C antibodies are coupled to cyanogen bromide (CNBr)-activated Sepharose 4B (Pharmacia). Presumably, actual manufacture involves much the same process and materials.

As generally described in this patent, but at very small scale, prothrombin complex concentrate is dissolved in buffer, filtered, centrifuged, and sterile filtered through a 0.8 µm filter. The sterile filtered and dissolved prothrombin complex concentrate is applied to the immunoaffinity column. Subsequently, the column is washed free of non-bound protein with the washing buffer, the bound Protein C is eluted by an elution buffer, and the fractions collected. The eluted protein C is dialyzed against a buffer. The protein C eluate is subjected to ultrafiltration and diafiltration steps. The obtained filtrate is then freeze-dried and virus inactivated by a one-hour vapor treatment at 80˚C..+-.5˚C. and at 1375.+-.35 mbar. The lyophilized, virus-inactivated material is then dissolved in a sterile isotonic NaCl solution and potentially present antibodies or serum amyloid P are eliminated by means of ion exchange chromatography on Q-Sepharose.R (Pharmacia). The purified solution is concentrated by means of an additional ultrafiltration and diafiltration stage. After this stage, 10 g albumin, 150 mmol NaCl and 15 mmol trisodium citrate per liter were added to the solution obtained. The pH of the solution was 7.5. Neither murine immunoglobulin nor factors II, VII, IX and X could be detected. Subsequently, the solution was sterile filtered, filled in containers and lyophilized. The specific activity was 14 units protein C per mg of protein. An amidolytic assay was used as the activity test, with protein C activated by means of Protac (from Pentapharm).

Comprehensive virus clearance studies have been performed for the following steps: polysorbate 80 (Tween-80) treatment alone or coupled with an ion exchange chromatography step (IEX I), and immunoaffinity chromatography (IAX) and vapor heating. In each study, the validity of the downscaled process was confirmed by measuring process and biochemical parameters and comparing these with data from the large-scale manufacturing process. For polysorbate 80 treatment and vapor heating, the robustness of virus clearance has been investigated by adjusting critical process parameters to levels least favorable for virus inactivation (e.g. temperature and incubation time for vapor heating). Virus clearance studies have shown log10 virus reduction: polysorbate 80 reduction of >5.1 for HIV-1, >4.7 for bovine viral diarrhea virus (BVDV; a model for hepatitis C virus), N.D. (not determined/applicable) for ick-borne encephalitis virus (TBEV; a model for hepatitis C virus), 2.5 for pseudorabies virus, >3.8 for hepatitis A virus, and 1.4 for mouse (murine) minute virus (MMV); for immunoaffinity chromatography, 5.7 for HIV-1, N.D. for BVDV, 4.8 for TBEV, 5.4 for pseudorabies virus, 3.1 for hepatitis A virus, and 3.6 for MMV; and vapor heating, 4.6 for HIV-1, >5.9 for BVDV, N.D. for TBEV, 5.9 for pseudorabies virus, ≥4.2 pseudorabies virus, and 1.2 for MMV. The minimal total viral inactivation/removal (in log10) for each virus is the total of the incremental inactivation/removal log amounts for each virus.

FDA class: Biologics BLA (125234/0)

Approval: Date = 20070327; original BLA

Indications:. [Full text of the "INDICATIONS AND USAGE” section of product insert/labelingl]

1.1 Severe Congenital Protein C Deficiency

CEPROTIN is indicated for patients with severe congenital Protein C deficiency for the prevention and treatment of venous thrombosis and purpura fulminans. CEPROTIN is indicated as a replacement therapy for pediatric and adult patients.

[Portion of the “What Ceprotin is and what it is used for” section of the “Package Leaflet” (product insert) in the European Union, Norway and Iceland]:

Ceprotin is used for purpura fulminans and coumarin induced skin necrosis in patients with severe congenital protein C deficiency.

Furthermore Ceprotin is used for short term prophylaxis in patients with severe congenital protein C deficiency if one or more of the following conditions are met: surgery of invasive therapy is imminent; while initiating coumarin therapy; when coumarin therapy alone is not sufficient; [and] when coumarin therapy is not feasible.

Since safety and efficacy data are not available in conditions other than severe congenital protein C deficiency, use should be limited to these conditions.

Status: Ceprotin was not yet been launched in the U.S. as of August 2007.

Ceprotin was approved in the European Union in July 2001 for treating purpura fulminans and coumarin-induced skin necrosis in patients with severe congenital Protein C deficiency, and for other uses (e.g., preparation for surgery) in Protein C deficient patients.

Note, Ceprotin is not approved for treatment of sepsis, as is Xigris.

Ceprotin was approved by FDA on March 30, 2007. The approval letter noted that Baxter’s “request for a waiver to the required reporting format for postmarketing periodic safety reports under 21 CFR 600.80 is granted. You may submit these reports using the Periodic Safety Update Report (PSUR) format as described in the ICH E2C guidance.”

Ceprotin has orphan designation in the U.S. and European Union. FDA granted the BLA priority review. Ceprotin is the first FDA approved therapy for patients with severe congenital Protein C deficiency.

In the U.S., Ceprotin has been available since 1998 to patients, most of them children, for compassionate use and through Baxter’s clinical trials.

Tech. transfer: The U.S. product insert cites 5,549,893 and unspecified pending patents. U.S. 5,549,893, “Use of protein C in the treatment of purpura fulminans,” assigned to Immuno AG (now Baxter), has four claims: 1. A method for the prophylaxis of purpura fulminans in a patient exposed to endotoxin, comprising the step of administering to said patient an effective amount of a concentrate of non-activated protein C; 2. A method according to claim 1, wherein said concentrate does not contain IgG; 3. A method of treating purpura fulminans in a patient exposed to endotoxin, comprising the step of administering to said patient an effective amount of a concentrate of non-activated protein C; [and] 4. A method according to claim 3, wherein said concentrate does not contain IgG.

Disease: Severe congenital Protein C deficiency is an ultra-orphan disease. Baxter reports, “Currently, there are fewer than 20 known cases of severe congenital Protein C deficiency in the United States.”

Severe congenital Protein C deficiency is a rare genetic/hereditary defect found in one to two newborns for every million births. This deficiency results in a hypercoagulable state, meaning there is an abnormal tendency for blood clotting. Patients with insufficient levels of functional Protein C experience abnormally high numbers of blood clots, including severe, often life-threatening blood clots in small blood vessels. Complete absence of functional Protein C is fatal. The disease manifests in children very early in life, often in utero or in the first few days of life. Clotting may occur in the blood vessels of the skin, eyes, brain, kidneys and throughout the body. If left untreated, clotting may result in blindness, severe brain damage, multi-organ failure, and death.

Patients with severe inherited Protein C deficiency must take oral or injected anticoagulant drugs on a regular basis to avoid blood clots. Ceprotin is intended to treat these patients when faced with a life-threatening situation from blood clots in the veins, or a severe skin and systemic blood clotting disorder known as purpura fulminans.

Trials: FDA reports, “The company [Baxter] enrolled all available patients for the pivotal trial. FDA approval was based on data from a pivotal multi-center, open- label, non-randomized, Phase II/III study, which evaluated the safety and efficacy of Ceprotin in subjects with severe congenital Protein C deficiency for the (on-demand) treatment of acute thrombotic episodes, such as purpura fulminans (PF), warfarin-induced skin necrosis (WISN), and other thromboembolic events, and for short-term or long-term prophylaxis. The study included 18 patients (nine male and nine female) ranging in age from newborn to 25.7 years. Ceprotin was effective in 94% of the episodes of PF. In the remaining 6% of patients, the treatment was found “effective with complications” because they required a dosage adjustment. Inadequate data were available for the treatment of WISN. When compared with the efficacy ratings for 21 episodes of PF (historical control group), subjects with severe congenital Protein C deficiency were more effectively treated with Ceprotin than those treated with other modalities, such as fresh frozen plasma or conventional anticoagulants. Ceprotin also demonstrated effectiveness in reducing the size and number of skin lesions in patients. Treatment with Ceprotin healed non-necrotic skin lesions after a median of four days, and necrotic skin lesions were healed after a median of 11 days. Seven patients took Ceprotin as a preventive measure before surgery or anticoagulation therapy and had no associated blood clotting complications. Eight patients who were given Ceprotin as a long term preventive measure did not experience the severe skin and blood clotting events associated with PF. Eighty percent of the treatments for blood clots in the veins were determined as ‘excellent’ while the other 20% were determined as ‘good.’ The most common adverse reactions in trials were rash, itching and lightheadedness.” In its clinical development, no serious adverse reactions with Ceprotin were reported.

Medical: Ceprotin is administered by intravenous injection. It should be administered at a maximum injection rate of 2 mL/minute, except for children with a body weight of < 10 kg, where the injection rate should not exceed a rate of 0.2 mL/kg/minute. The dose, administration frequency and duration of treatment depends on the severity of the Protein C deficiency, the patient’s age, the clinical condition of the patient and the patient’s plasma level of protein C, i.e., the dose regimen should be adjusted according to the pharmacokinetic profile for each individual patient.

An initial dose of 100-120 IU/kg for determination of recovery and half-life is recommended for acute episodes and short-term prophylaxis. Subsequently, the dose should be adjusted to maintain a target peak protein C activity of 100%. After resolution of the acute episode, patients should continue on the same dose to maintain trough Protein C activity. In patients receiving prophylaxis, higher peak protein C activity levels may be warranted in situations of an increased risk of thrombosis (e.g., infection, trauma, or surgery). Maintenance of trough Protein C activity levels above 25% is recommended. These dosing guidelines are also recommended for neonatal and pediatric patients.

Market: The Average Wholesale Price (AWP) is not available (not in the 2007 Red Book).