Sirolimus for Autoimmune Disease of Blood Cells

Treatment for patients with autoimmune destruction of blood cells is poor. The part of the body that fights infections is called the immune system and white blood cells (WBCs) are part of the immune system. Normally, a person's body creates WBCs to fight infections and eliminates WBCs which have stopped helping the body function. Patients with autoimmune destruction of blood cells have difficulty eliminating old WBCs. The abnormal WBCs build up and can damage other healthy cells, which can lead to anemia, fatigue, jaundice, internal bleeding, infection, and cancer. Few effective medications exist for treatment for patients with autoimmune cytopenias and those commonly used are fraught with side effects. Nevertheless, as scientific understanding of autoimmune diseases has improved, more directed and less toxic therapies are becoming available. A number of groups have been studying the efficacy of a medication called sirolimus in patients with autoimmune diseases. This medicine has been FDA-approved for over 20 years. Sirolimus is a medicine used in children with other diseases. Sirolimus works, in part, by eliminating old and abnormal WBCs. Our group and others have shown that sirolimus is effective in mice with autoimmunity and in children with a rare condition called Autoimmune Lymphoproliferative Syndrome (ALPS). We believe sirolimus will help children with autoimmune cytopenias. We believe it will improve their symptoms and make them less sick. We propose to study sirolimus in children with chronic and/or refractory autoimmune cytopenias.

Patients with autoimmune destruction of hematopoietic cells frequently have severe and debilitating disease requiring aggressive and frequent medical management. These patients are often treated with non-specific immunosuppressive medications with limited efficacy and untoward side-effect profiles. We have been investigating the use of an immunosuppressive and anti-cancer agent, sirolimus in patients with an autoimmune cytopenias syndrome: Autoimmune Lymphoproliferative Syndrome (ALPS). ALPS is a primary immune deficiency caused by mutations in the Fas apoptotic pathway, leading to abnormal lymphocyte survival. Clinical manifestations in patients with ALPS typically include autoimmune cytopenias, lymphadenopathy, hepatosplenomegaly, and a propensity to develop secondary malignancies. Thus, far we have found excellent results albeit the total number of patients treated is small. Sirolimus is a signal transduction inhibitor with a tolerable side effect profile. Sirolimus has two properties making it an attractive agent to treat patients with autoimmune cytopenias syndromes, including ALPS. First, sirolimus induces apoptosis in normal and abnormal white blood cells, the cell type dysregulated in patients with autoimmune disease. In addition, sirolimus increases a T cell subset called Regulatory T cells (Tregs). Tregs are a cell population designed to suppress the immune system and control autoimmunity. These combined properties make sirolimus unique as compared with other immunosuppressive agents. Ample preclinical and clinical data exists demonstrating sirolimus in effective in patients with autoimmunity. Accordingly, we hypothesize sirolimus is a safe and efficacious medication for patients with autoimmune destruction of blood cells.. We plan to confirm our hypotheses by performing a pilot series in children with autoimmune cytopenias who are either refractory to standard therapy or have significant toxicity from standard treatments. Our primary aim is to define the toxicities of administration of oral sirolimus in children with autoimmune cytopenias. Our secondary aims are to evaluate the efficacy of sirolimus in children with autoimmune cytopenias, to determine the trough levels of sirolimus when used in these patients, and to evaluate the effects of sirolimus on intracellular targets of mammalian target of rapamycin (mTOR). We intend to enroll 50 children with autoimmune cytopenias and treat for a 6 month period, however, if we find sirolimus is effective, we anticipate these children will continue to take sirolimus for a longer period of time. We anticipate the results of this work will establish sirolimus is an effective and well tolerated medication and will lead directly to a larger national phase II clinical trial.

Autoimmune Pancytopenia, Autoimmune Lymphoproliferative Syndrome (ALPS), Evans Syndrome, Idiopathic Thrombocytopenic Purpura, Anemia, Hemolytic, Autoimmune, Autoimmune Neutropenia, Lupus Erythematosus, Systemic, Inflammatory Bowel Disease, Rheumatoid Arthritis

ALPS, Autoimmune, Cytopenias, Treatment, Sirolimus, Rapamycin, Lymph Nodes, Spleen, Hemolytic Anemia, Immune Thrombocytopenia, Neutropenia, ITP, Lupus

Tablet or liquid; taken once or twice daily; dosage is based on establishing a serum trough of 5-15 ng/ml by high-performance liquid chromatography (initial loading dose of 3 mg/m2 then 2.5 mg/m2 with adjustment based on serum trough)

Grade 3 toxicities are those that are considered severe or medically equivalent requiring hospitalization or prolonged hospitalization (according to CTCAE criteria 3.0). Grade 4 toxicities are those that are life-threatening (urgent intervention indicated) (according to CTCAE criteria 3.0).

Complete response (CR) is complete resolution in all autoimmune cytopenias (neutropenia, anemia thrombocytopenia) maintained for more than two months, combined with an ability to wean off corticosteroids and/or other immunosuppressive medication. Partial response (PR) is improvement in any cytopenias by at least one grade, lasting more than two months, without worsening any other cytopenias or stable disease with the ability to wean corticosteroids and/or immunosuppressive medications by at least 50%. No response (NR) is no change in cytopenias with treatment, and the inability to wean corticosteroids or other immunosuppressive medications. Progressive disease (PD) refers to obtaining a CR or PR by the 3 month observation and relapsing or progressing by the 6 month observation, leading to cessation of study drug.

Complete response (CR) is complete resolution of any lymphadenopathy and splenomegaly for at least two months. Partial response (PR) is a reduction in size of at least 50% of lymphadenopathy or splenomegaly for at least two months. No response (NR) is no change or < 50% reduction in lymphadenopathy or splenomegaly. Progressive Disease (PD) is obtaining a CR or PR by the 3 month observation and relapsing or progressing by the 6 month observation, leading to cessation of study drug. Not Applicable (N/A) is there is no evidence of disease (No pathologic lymphadenopathy or splenomegaly at time of enrollment).

Inclusion Criteria: Age > 12 months and < 30 years at the time of study entry Diagnosis of autoimmune cytopenias requiring treatment with medications At least one of the following: Autoimmune Neutropenia, Autoimmune Hemolytic Anemia, and/or Autoimmune Thrombocytopenia Must be proven autoimmune by either a documented autoantibody (positive direct anti globulin test, positive anti-neutrophil, and/or anti-platelet antibody) and/or a documented clinical response to immunosuppression Autoimmune Cytopenias can be idiopathic (Idiopathic Thrombocytopenic Purpura (ITP), Autoimmune Hemolytic Anemia (AIHA), Autoimmune Neutropenia (AIN), or Evans syndrome) or secondary to one of following conditions: Lupus, Rheumatoid Arthritis (RA), ALPS (Autoimmune Lymphoproliferative Syndrome), or Inflammatory bowel disease (IBD) Patients must have chronic disease diagnosed by either a documented cytopenia syndrome (Lupus, ALPS, RA, or IBD), or by having Evans syndrome defined as idiopathic destruction of multiple blood cell types, and/or by having disease >6 months Patients must be refractory to or unable to tolerate standard front-line therapies for autoimmune cytopenias (corticosteroids and/or IVIG) Patients may be taking second-line agents for autoimmune cytopenias (mycophenolate mofetil, cyclosporine, tacrolimus, mercaptopurine, and/or methotrexate) at time of study entry; however, attempts should be made to wean these agents. Patients may not stay on a combination of sirolimus and a calcineurin inhibitor for greater than 4 weeks Informed consent/assent must be obtained prior to initiating treatment Patient must be able to consume oral medication in the form of tablets or solution Exclusion Criteria: Pregnancy or breast feeding Uncontrolled infection Known allergy to Sirolimus or its components Patients with a documented malignancy on therapy or not in remission Patients who do not meet organ function requirements listed in protocol Patients with a documented history of severe combined immunodeficiency or human immunodeficiency virus infection (HIV)

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Teachey DT, Manno CS, Axsom KM, Andrews T, Choi JK, Greenbaum BH, McMann JM, Sullivan KE, Travis SF, Grupp SA. Unmasking Evans syndrome: T-cell phenotype and apoptotic response reveal autoimmune lymphoproliferative syndrome (ALPS). Blood. 2005 Mar 15;105(6):2443-8. doi: 10.1182/blood-2004-09-3542. Epub 2004 Nov 12.

Teachey DT, Greiner R, Seif A, Attiyeh E, Bleesing J, Choi J, Manno C, Rappaport E, Schwabe D, Sheen C, Sullivan KE, Zhuang H, Wechsler DS, Grupp SA. Treatment with sirolimus results in complete responses in patients with autoimmune lymphoproliferative syndrome. Br J Haematol. 2009 Apr;145(1):101-6. doi: 10.1111/j.1365-2141.2009.07595.x. Epub 2009 Feb 4.

Bride KL, Vincent T, Smith-Whitley K, Lambert MP, Bleesing JJ, Seif AE, Manno CS, Casper J, Grupp SA, Teachey DT. Sirolimus is effective in relapsed/refractory autoimmune cytopenias: results of a prospective multi-institutional trial. Blood. 2016 Jan 7;127(1):17-28. doi: 10.1182/blood-2015-07-657981. Epub 2015 Oct 26.