INTERLEUKIN-1 RECEPTOR ANTAGONIST DECREASE8 SEVERITY OP ACUTE PANCREATITIS
TECHNICAL FIELD
The present invention relates to a method for treating acute pancreatitis.
BACKGROUND O? THE INVENTION Acute pancreatitis is a common clinical problem which remains evasive of specific therapy. Each year more than 15,000 admissions to U.S. hospitals are caused by acute pancreatitis. It is most often caused by alcoholism or biliary tract disease. Less commonly, it is associated with hyperlipemia, hyperparathyroidism, abdominal trauma, vasculitis or uremia. The average length of hospitalization for the disease is 12.4 days, with a significant number of patients staying much longer because of associated complications.
There are no medical therapies or pharmacologic agents currently available which have been shown to decrease the severity, duration, complication rate, or mortality for this common disease. Over the past decade, a somatostatin analog has undergone several clinical, as well as laboratory trials, in an attempt to show beneficial
effects of suppressing pancreatic exocrine function pharmacologically during acute pancreatitis. The majority of investigators have shown beneficial effects only with treatment prior to the onset of pancreatitis, and disappointing results when somatostatin was given after the acute inflammatory process had started.2'3'4
With more recent understanding of the complex mechanisms of tissue and cellular injury associated with inflammatory processes, such as sepsis,
5 it is reasonable to assume that many of these inflammatory processes are not specific to sepsis syndromes alone. Several authors have suggested that much of the intrinsic pancreatic damage seen in acute pancreatitis is due to the release of toxic substances from acrophages and other white blood cells which migrate into the damaged
7 , 8'
9 , 10'
11 '
12 These substances are known as cytokines and are now well known as mediators of inflammation and tissue injury.
A curious aspect of acute pancreatitis is the systemic response which is seen following inflammation initiated within the pancreas. Acute pulmonary, renal, and hepatic failure, generalized water retention, hypocalcemia, hypoxia, and acid/base disturbances are all possible complications of pancreatitis. The mechanism for
complications of pancreatitis. The mechanism for the involvement of these other organ systems is unclear, but probably involves activation of the cytokine cascade, including interleukin-1 (IL-1) , interleukin-6 (IL-6) , and tumor necrosis factor (TNF) in a manner not significantly different from sepsis syndromes.I2'iJ'i4 i5 Serum levels of these peptides have been shown to correlate to a high degree with the severity of acute pancreatitis in humans, and can also be demonstrated within pancreatic ascites.I,2'i5
The administration of IL-1 to rabbits17,18,19,20 and primates2 has been s) own to result in hypotension, tachycardia, lung edema, renal failure, and, eventually, death, depending on the dose. These signs and symptoms are similar to those demonstrated by patients with severe acute pancreatitis. When the serum from the IL-1 treated animals is examined, the elevation of other cytokines is evident, mimicking the levels seen in acute pancreatitis in humans.11 >12 There is a large body of evidence currently available which supports the role of IL-1 as a major mediator of the systemic response to diseases such as sepsis and pancreatitis and as an activator of the remaining members of the cytokine cascade.5 Fischer et a.1.21 demonstrated that the
administration of a naturally occurring antagonist to IL-1 will significantly blunt the cytokine cascade and improve survival in baboons given a lethal dose of live bacteria. In this study, IL-1 receptor antagonist (IL-lra) significantly attenuated the decrease in mean arterial pressure and cardiac output and improved survival over control. The systemic IL-1 and IL-6 responses observed as a result of the bacteremia were diminished significantly, correlating with a decrease in the systemic response to the sepsis.
Studies by Aiura et al .20 have shown that IL-lra is protective in a rabbit model of hypotensive gram-positive septic shock. The administration of IL-lra in this animal model has been shown to maintain mean arterial pressure compared to control, as well as decreasing lung water and maintaining urine output. This work demonstrated the role of IL-1 and the protective role of IL-lra in gram-positive shock which was thought to be due to a separate mechanism from gram-negative shock. The common pathway for the systemic manifestations of these two different models of shock has been shown to involve IL-1 as a central mediator. Evidence is mounting for the role of IL-1 as the principal mediator in a patient's clinical response to multiple different
stresses regardless of the etiology (including acute pancreatitis) .
U.S. patents 4,522,827 and 4,902,708 disclose methods of treating acute pancreatitis. However, none of these patents take into effect the specific pathology of the disease, thereby proposing treatments which are not specific and are directed to the symptoms only, not the underlying mechanism. U.S. patent 5,196,402 discloses the use of S-adenosyl methionine for the use of treatment of pancreatitis in the context of a complication in the graft rejection in pancreas transplant, a very uncommon procedure. The patent does not address acute pancreatitis as a disease in the nontransplant patient. The vast majority of cases of pancreatitis are not associated with pancreatic transplants.
Treatments are needed which take into account that the local, as well as systemic, effects seen during acute pancreatitis are due to activation of the cytokine cascade whereby proximal inhibition of this cascade will decrease the severity of the inflammatory process.
SUNMARY OF THE INVENTION AND ADVANTAGES
According to the present invention, a method for treating acute pancreatitis is provided. The method comprises administering to a person afflicted with that condition an effective amount of Interleukin-1 receptor antagonist (IL-lra) or a pharmaceutically acceptable salt thereof.
BRIEF DESCRIPTION OF THE DRAWINGS Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: FIGURE 1 is a graph showing the pancreatic wet weight in controls (shaded) , IL-lra lOmg/kg pretreatment (solid) , IL-lra 10 mg/kg post- treatment (diagonal) , and untreated disease control (cross-hatching) with * indicating p<0.01 compared to no treatment;
FIGURE 2 is a graph showing the serum amylase levels in groups as in Figure 1 with * indicating p<0.05 compared to no treatment;
FIGURE 3 is a graph showing the serum lipase levels in groups as in Figure 1 with * indicating p<0.0001 compared to no treatment;
FIGURE 4 is a graph showing the serum interleukin-6 levels in groups as in Figure 1 with * indicating p<0.0001 compared to no treatment; and
FIGURE 5 is a graph showing the serum TFN levels in groups as in Figure 1 with * indicating P<0.0001 compared to no treatment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT IL-lra is a naturally occurring peptide secreted by macrophages in response to many of the same stimuli which cause the secretion of IL-1 itself. IL-lra is the only known naturally occurring antagonist to the cytokines and recognizes receptors on various cell types and blocks IL-1 mediated responses by occupying the receptor.17,18,19,20,21 In humans, IL-lra is a naturally occurring group of molecules; three forms have been characterized (two glycosylated and one non-glyσosylated) . According to the present invention, a person afflicted with that condition is administered an effective amount of Interleukin-1 receptor antagonist (IL-lra) or a pharmaceutically acceptable salt thereof. The safety of IL-lra after intravenous administration has been demonstrated during the past three years in mice, rats, rabbits, dogs.
primates, and humans.17,19,20,21 ,22,23,24 In normaι volunteers, IL-lra has been demonstrated to have a half-life of approximately two hours after intravenous administration and the plasma clearance of IL-lra appeared to correlate with creatine clearance."25 Hence, there already exists a regimen for IL-lra administration for humans.
The IL-lra to be used can be administered in combination with other drugs or singly consistent with good medical practice. The other drugs can be somatostatin or an analog (i.e., Sandostatin®) and prostaglandin inhibitors (i.e., non-steroidal, anti-inflammatory drugs such as aspirin, indo ethacin, ibuprofen, etc.). Additionally, steroids or other drugs designed to suppress the immune system and other synthetic or recombinant antagonists or blockers to cytokines (e.g., soluble TNF receptors, soluble IL-1 receptors, soluble IL-6 receptors or others; monoclonal antibodies to IL-1, IL-6, TNF or others, etc.) can be administered. Further, nitric oxide inhibitors or antagonists, free radical scavengers or anti-oxidants, antagonists or blockers of complement, ecosinoids or their antagonists and antibiotics, as appropriate, can also be administered.
The IL-lra is administered and dosed in accordance with good medical practice, taking into account the clinical condition of the individual patient, the s_te and method of administration, scheduling of administration, and other factors known to medical practitioners. The "effective amount" for purposes herein is thus determined by such considerations as are known in the art.
In the method of the present invention, the IL-lra can be administered in various ways. It should be noted that the IL-.ira can be administered as the compound or as pharmaceutically acceptable salt and can be administered alone or in combination with pharmaceutically acceptable carriers. The compounds can be administered orally or parenterally including intravenous, intraperitoneally, intranasal and subcutaneous administration. Implants of the compounds are also useful. The patient being treated is a warm- blooded animal and, in particular, mammals including man.
When administering the IL-lra parenterally, the pharmaceutical formulations suitable for injection include sterile aqueous solutions or dispersions and sterile powders for reconstitution into sterile injectable solutions or dispersions. The carrier can be a solvent or
dispersing medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, liquid polyethylene glycol, and the like) , suitable mixtures thereof, and vegetable oils. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Nonaqueous vehicles such a cottonseed oil, sesame oil, olive oil, soybean oil, corn oil, sunflower oil, or peanut oil and esters, such as isopropyl myristate, may also be used as solvent systems for compound compositions. Additionally, various additives which enhance the stability, sterility, and isotonicity of the compositions, including antimicrobial preservatives, antioxidants, chelating agents, and buffers, can be added. Prevention of the action of microorganisms can be ensured by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, and the like. In many cases, it will be desirable to include isotonic agents, for example, sugars, sodium chloride, and the like. Prolonged absorption of the injectable pharmaceutical form can be brought about by the use of agents delaying absorption, for example, aluminum monostearate and gelatin.
According to the present invention, however, any vehicle, diluent, or additive used would have to be compatible with the compounds.
Sterile injectable solutions can be prepared by incorporating the compounds utilized in practicing the present invention in the required amount of the appropriate solvent with various of the other ingredients, as desired.
A pharmacological formulation of the IL-lra can be administered to the patient in an injectable formulation containing any compatible carrier, such as various vehicle, adjuvants, additives, and diluents; or the compounds utilized in the present invention can be administered parenterally to the patient in the form of slow- release subcutaneous implants or targeted delivery systems such as polymer matrices, liposomes, and microspheres. An implant suitable for use in the present invention can take the form of a pellet which slowly dissolves after being implanted or a biocompatible delivery module well known to those skilled in the art. Such well known dosage forms and modules are designed such that the active ingredients are slowly released over a period of several days to several weeks.
Examples of well-known implants and modules useful in the present invention include: U.S. Patent No. 4,487,603, which discloses an implantable micro-infusion pump for dispensing medication at a controlled rate; U.S. Patent No. 4,486,194, which discloses a therapeutic device for administering medicants through the skin; U.S. Patent No. 4,447,233, which discloses a medication infusion pump for delivering medication at • a precise infusion rate; U.S. Patent No. 4,447,224, which discloses a variable flow implantable infusion apparatus for continuous drug delivery; U.S. Patent No. 4,439,196, which discloses an osmotic drug delivery system having multi-chamber compartments; and U.S. Patent No. 4,475,196, which discloses an osmotic drug delivery system. These patents are incorporated herein by reference. Many other such implants, delivery systems, and modules are well known to those skilled in the art. A pharmacological formulation of the
IL-lra utilized in the present invention can be administered orally to the patient. Conventional methods such as administering the compounds in tablets, suspensions, solutions, emulsions, capsules, powders, syrups and the like are usable. Known techniques which deliver the IL-lra orally or
intravenously and retain the biological activity are preferred.
In one embodiment, the IL-lra can be administered initially by intravenous injection to bring blood levels of IL-lra to a suitable level. The patient's IL-lra levels are then maintained by an oral dosage form, although other forms of administration, dependent upon the patient's condition and as indicated above, can be used. The quantity of IL-lra to be administered will vary for the patient being treated and will vary from about 100 ng/kg of body weight to 100 mg/kg of body weight per day and preferably will be from 10 μg/kg to 10 mg/kg per day. In one preferred embodiment, if the patient is diagnosed with severe acute pancreatitis, then the patient will be aggressively treated for 72 hours and will receive intravenously a loading dose of 100 mg in a total volume of lOrnl followed by a 72-hour continuous infusion. The continuous infusion will consist of 2.0mg/kg/hr. The infusion will be done by preparing 100ml of the drug in saline for each 12-hour period. It will be infused by utilizing a volumetric infusion pump at a rate of 8.3 ml/hr. Any residual IL-lra at the end of the 12 hours will be infused before the subsequent 12-hour infusion is initiated. At the
completion of the 72-hour infusion, the patient is evaluated and, based on the patient's condition, infusion will be continued, administration switched to oral dosage, or the drug discontinued. The practice and utility of the present invention is shown in the following example:
MATERIALS AND METHODS The specification and claims provide guidance for the use of the invention in humans. The Investigator's Handbook25 provided by the National Cancer Institute (page 23) indicates that the starting dose for Phase I trials is based on the mouse equivalent LD10. Further, the manual (page 22) indicates that animal studies carried out prior to Phase I trials provide the investigator with a prediction of the likely effects.27 Therefore, the presented rodent model data is not only acceptable in determining human doses and protocols, but is considered highly predictive.
Acute edematous, necrotizingpancreatitis was induced in adult male Swiss mice weighing more than 35 grams using caerulein - an analog of cholecystokinin. Mice were divided into four groups with three of the groups receiving caerulein 50 μg/kg by intraperitoneal (IP) injection in four
doses over three hours as previously described.2, 7 ,9,12 ,28,29
Group 1 was a control group (n-9) which received only IP saline injections. Group 2 (n=12) was an untreated disease control. Group 3 (n=12) received three injections (10 mg/kg/hr) starting one hour prior to induction of pancreatitis. Group 4 (n=12) received three injections (10 mg/kg/hr) starting one hour after induction of pancreatitis.
The IL-lra used in this study is produced in E. coli by Synergen Corporation (Boulder, CO) by utilizing recombinant DNA technology and is identical to the non-glycosylated human form of human IL-lra except for the addition of one terminal methionine amino acid.
After nine hours, all animals were euthanized, the blood collected, and the pancreata surgically excised and weighed. Serum was assayed for amylase, lipase, IL-6, and TNF levels. Each pancreas was fixed, stained, and graded histologically in a blinded fashion for interstitial edema, granulocyte infiltration, acinar vacuolization, and acinar cell necrosis as described previously.7'27'28 Additionally, serum levels of IL-lra were determined, therefore allowing comparisons between dosage, serum level,
systemic cytokine response, and degree of pancreatic damage.
IL-6, 11-1, IL-lra,and TNF were measured by commercially available ELISA kits (Genzyme Corp. , Boston, MA) . All specimens were run in triplicate. Serum levels of amylase and lipase were measured on a Kodak Ectachem 700 automated analyzer (Eastman Kodak Company, Rochester, NY) .
Histologic slides were prepared as is known in the art after rapid excision and subsequent fixation in 10% formalin. The tissues were paraffin embedded as is known in the art and then stained with Hematoxylin and Eosin in a standard fashion. These slides were examined and graded in a blinded fashion by a board certified pathologist.
Results In these experiments, acute pancreatitis was induced in 45 mice using caerulein. Acute edematous, necrotizing pancreatitis is present within an hour of caerulein injection and reaches a peak effect approximately nine hours later. By treating mice with IL-lra prior to or after the induction of pancreatitis, applicants were able to show a significant decrease in pancreatic wet weight (p<.01), serum amylase (p<.05), lipase (p<.0001), and IL-6 (p<.0001) as shown in Figures
1-4 and Table I, respectively. TNF (p<0.0001) was also significantly reduced (Figure 5) . All statistics noted are significant by two-tailed Wilcoxon test. Additionally, there was a decrease in the number of polymorphonuclear white blood cells (PMNs) within the capillaries of the lungs and pancreas. Histologic studies of these pancreata were performed in a blinded fashion and showed a significant decrease (p<.05) in total organ edema, acinar necrosis, acinar vacuolization, and inflammation in those animals treated with IL-lra. An important finding in these experiments was that treatment with IL-lra within two hours after the onset of pancreatitis was nearly as protective as pretreatment.
These series of experiments were repeated using both higher and lower does of Il-lRa. In one experiment, all animals received IL-lra at a dose of 100 mg/kg/hrX3. All the previous findings were confirmed, but no significant benefit could be found with the higher dose. When the dose of IL-lra was decreased to 1 mg/kg/hrx3, the benefits were seen in all categories except amylase levels. This dose, however, did not show quite as much decrease in wet weight or the levels of IL-6 and TNF as did the 10 mg/kg/hrx3 dose. These dose response experiments confirm the efficacy of IL-lra
in the treatment of pancreatitis when proper levels of the drug are maintained.
The example provides guidance for the use of the invention in humans. The Investigator's Handbook26 provided by the National Cancer Institute (page 23) indicates that the starting dose for Phase I trials is based on the mouse equivalent LD10. In fact. Phase I trials of IL-lra have been completed.24 Further, the manual (page 22) indicates that animal studies carried out prior to Phase I trials provide the investigator with a prediction of the likely effects. 2 Therefore, the presented rodent model data is not only acceptable in determining human doses and protocols but is considered highly predictive. Based on the available data from the Phase I trials and Phase II trials in the treatment of sepsis'30 combined with the present invention allows the treatment of pancreatitis in humans. Further, the cytokine activation in fulminant pancreatitis is similar to that of sepsis. The blockade of the cascade applicants have shown is similar to that shown in animal and human studies using IL-lra for sepsis. A better understanding of the role played by specific cytokines in this systemic reaction has provided insight into effective therapies for severe
pancreatitis, in particular the therapeutic use of IL-lra in acute pancreatitis.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
TABLE r
GROUP WET WT AMYLASE LIPASE IL-6 TNF
(mg) (SU) (IU) (ng/kg) (ng/kg)
1 188±0.1 2204±156 715±58 54±5 63±9
2 493 29465 22259 315 442
±.04* ±1756* ±3155* ±51* ±30*
3A 320 21480 8976 65 136
±.02** ±2393** ±1685** ±11** ±3**
4A 341 28088 11916 118 101
±.04** ±4494** ±2648** ±17** ±10**
Results are expressed as mean ± SEM, significance accepted if p < 0.05 by two-tailed Wilcoxon test.
* compared to control (Group 1)
** compared to untreated pancreatitis (Group 2)
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