INM-004

Hemolytic Uremic Syndrome (HUS) is a foodborne disease which mainly affects children. It is caused by Escherichia coli bacteria, which release a toxin called Shiga toxin within the body. This infectious form of HUS, defined as STEC-HUS, can cause sporadic cases or outbreaks, as observed in different countries. Argentina has the highest incidence of STEC-HUS worldwide. The disease is endemic, representing approximately 95% of all HUS cases nationwide.
STEC-HUS generally begins with diarrhea (with or without blood), and can also cause fever, abdominal pain, and cramps. Then the child may have pallor, altered consciousness, decreased urine output, seizures, and other symptoms. Although death is uncommon (it occurs in 2-4% of cases), it is a very serious disease that mainly affects the kidneys, and also other organs such as the brain. About half of children need to undergo a risky procedure such as dialysis (due to malfunctioning kidneys); and most of them also receive blood transfusions.
Around 30% of the patients are left with lifelong consequences that can range from permanent kidney damage to the need for a transplant.
So far there is no drug, antibiotic or vaccine to prevent or treat HUS. Current treatment protocols include hospitalization for all patients with HUS, and supportive therapy such as hydration and salt intake. Support therapy is not a specific treatment, but rather helps the body better defend itself against the disease.
The purpose of this study is to establish whether it is safe and effective to treat patients who are diagnosed with STEC-HUS, with INM004 (study drug). INM004 is an investigational product "Fraction F(ab')2 of Equine Shiga Antitoxin Immunoglobulin". It is a concentrated and sterile serum obtained from healthy horses immunized against Shiga toxin that contains antibodies capable of neutralizing it.
The initial hypothesis is that INM004 would neutralize the entry of Shiga toxin into the body's cells thus preventing the consequent toxic damage. With the proposed treatment, INM004 would eliminate the Shiga toxin, preventing the progression of HUS symptoms and its serious complications (such as the need for and duration of dialysis, duration of hospital stays, as well as neurological, cardiovascular, intestinal complications, among others) which are associated with high morbidity and mortality. This treatment could then have an impact in health costs of STEC-HUS as well as the social costs.

The investigational medicinal product (IMP), INM004, proposes to neutralize the toxin in the bloodstream to prevent the interaction of the Stx with the specific receptor, by means of a polyclonal antibody to be administered upon the appearance of symptoms (bloody diarrhea) and diagnosis of infection by STEC, thereby preventing the action of the toxin in the body. Thus, the initial hypothesis for examination is for the prevention of the full expression of HUS, based upon presumptive clinical, biochemical, and other biological evidence suggesting a risk of HUS at the time of treatment application. The polyclonal antibody (F(ab')2 fragment) is obtained by processing the serum of equine animals previously immunized against engineered Stx1B and Stx2B immunogens.
INM004 could be administered at the earlier stages of STEC disease since subjects with STEC diarrhea are more likely to benefit from Stx neutralizing antibodies before the development of extra-intestinal manifestations and HUS. Neutralizing equine anti-Stx F(ab')2 antibodies (INM004) have the objective of preventing the development of HUS by blocking the circulating toxins in patients infected with STEC. Therefore, INM004 may be used in patients with a clinical manifestation of bloody diarrhea and a positive Stx result in feces. Early interruption of the Stx mediated cascade is expected to prevent the development of HUS, alleviate the severity of the illness, the rate of complications and the incidence/duration of hospitalizations. Therefore, patients in the early phases of the disease will be targeted in this study, ie, children who seek medical care due to diarrhea associated with STEC infection before HUS development.