A Pilot Study Evaluating the Use of mTor Inhibitor Sirolimus in Children and Young Adults With Desmoid-Type Fibromatosis

Desmoid-type fibromatosis (or desmoid tumor) represents an intermediate grade neoplasm with a striking predilection for locally invasive growth and recurrence following resection. It occurs in children as well as young adults. As a typically localized disease, the historical standard of care for treatment has been surgical resection, with or without ionizing radiation. In some cases where surgical resection or radiation is not feasible, chemotherapy has been used. Two clinical trials conducted in the Pediatric Oncology Group (POG) and the Children's Oncology Group (COG) evaluated the role for either low intensity or non-cytotoxic chemotherapy for children with desmoid tumor that is not amenable to standard therapy. These were largely empirical treatment strategies or based on somewhat anecdotal observations. By better understanding desmoid tumor biology, even more effective therapy targeting a particular protein that is central to the disease can be developed.

Desmoid tumor is well-known to be associated with deregulation of the Adenomatous Polyposis Cell/beta-catenin (APC/?-catenin pathway). This is true of familial cases associated with Gardner's Syndrome and also in sporadic desmoid tumor, nearly all of which display histological or molecular evidence of Adenomatous Polyposis Cell/beta-catenin (APC ?-catenin) pathway activation (Alman et al., 1997; Lips et al., 2009). Several new pieces of evidence support the concept that deregulation of the mammalian target of rapamycin (mTOR) cell proliferation/survival pathway may play an important role in tumor biology when the APC/?-catenin pathway is disrupted. Sirolimus, a drug that inhibits mammalian target of rapamycin (mTOR), is currently being evaluated as an anti-cancer agent in a variety of tumor types, but it has not been previously studied in desmoid tumor.

The investigators are conducting this pilot study to begin to explore whether mTOR inhibition may be beneficial for children and young adults with desmoid tumor.

Inclusion Criteria:

• Must be less than 30 years of age at time of original diagnosis
• Must have biopsy-proven desmoid tumor (or aggressive fibromatosis). For patients with recurrent disease, a biopsy is not required at the time of recurrence
• Patients known to have germ-line adenomatous polyposis coli (APC) mutations or clinical manifestations of Familial Adenomatous Polyposis(FAP)/Gardner's syndrome can be included

• Patients must have surgery planned to remove the desmoid tumor and either:

  • the desmoid tumor has already recurred after a prior surgery or
  • the newly diagnosed and/or previously unresected disease is judged to be at high risk for recurrence due to its size (>5 centimeters) or location at an anatomic site making it unlikely to be resected with negative margins (eg. adjacent to neurovascular structures)
• There must be a commitment by the surgical team to resect the primary tumor within 3 days following the 4 weeks of sirolimus unless the clinical situation at the time of resection suggests that these interventions are not in the patient's best interest

• Concomitant medication restrictions:

  • Patients may have received prior chemotherapy (excluding prior mTOR inhibitors)
  • Use of steroids for non-tumor indications (for example: asthma or severe allergic reaction) is permitted
• Patients must have a Karnofsky performance status of greater than or equal to 50 for patients older than 16 years of age or Lansky performance status of greater than or equal to 50 for patients less than or equal to 16 years of age.
• Patients must have a life expectancy of greater than or equal to 8 weeks.

• Patients must have recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study

  • Myelosuppressive chemotherapy: Must not have received within 2 weeks of entry onto this study (4 weeks if prior nitrosourea)
  • Biologic (anti-neoplastic agent): at least 7 days since the completion of therapy with a biological agent
  • Stem Cell Transplant (SCT): No evidence of active graft versus host disease. For allogeneic SCT, greater than or equal to 6 months must have elapsed.
• Patients must be able to consume oral medication in the form of tablets or solution

• Patients must have normal laboratory values as defined below:

  • Creatinine clearance or radioisotope Glomerular Filtration Rate ? 70millileters/minute/1.73 meters2 or a normal serum creatinine based on age/gender

• Hepatic: Adequate liver function is defined as:

  • Total bilirubin less than or equal to 1.5 x upper limit of normal (ULN)for age, and
  • Serum glutamic pyruvic transaminase (SGPT) less than or equal to 2.5 x upper limit normal (ULN) for age

• Hematologic function: Adequate bone marrow function is defined as:

  • Absolute Neutrophil Count (ANC) greater than or equal to 1 x 10 to the ninth/Liter
  • Hemoglobin greater than or equal to 10 gram/deciliter
  • Platelet count greater than or equal to 100 x 10 to the ninth/Liter
• Female patients must have a negative pregnancy test
• Female patients who are lactating must agree to stop breast-feeding
• Sexually active patients of childbearing potential must agree to use effective contraception
• Patients must be able to cooperate fully with all planned protocol therapy
• Signed informed consent MUST be obtained from patient or parent/legal guardian (if patient is less than 18 years of age). Consent must be signed prior to any study procedures and study entry

Exclusion Criteria:

• Patients with other fibroblastic lesions or other fibromatoses are NOT eligible.

• Concomitant medication restrictions

  • Patients may NOT have received prior mTor inhibitors
  • Growth factor(s): Must not have received within 1 week of entry onto this study.
• Patients must not be known to be Human Immunodeficiency Virus positive. Testing for Human Immunodeficiency Virus is not mandatory.
• Patients must not be taking medicines known to influence sirolimus metabolism

• Desmoid Tumor Research Foundation
• Pfizer