A Trial of Letrozole in Pulmonary Lymphangioleiomyomatosis With or Without Measurable Tumors or Lymph Nodes
Lymphangioleiomyomatosis, or LAM, is an uncommon, progressive, cystic lung disease that
predominantly affects young women. Pulmonary parenchymal changes consistent with LAM are
found in about one third of women with tuberous sclerosis complex (TSC), an autosomal
dominant tumor suppressor syndrome. LAM also occurs in a sporadic form that is not
associated with germ line mutations in TSC genes. Recent evidence that recurrent LAM after
lung transplantation results from seeding of the graft from a remote source and suggests a
metastatic mechanism for the disease.
Since LAM occurs almost exclusively in women, and exposure to estrogen either exogenously or
during pregnancy can exacerbate LAM, estrogen suppression might be expected to prevent or
delay progression of disease. In preclinical studies, estrogen induces the growth of
TSC2-deficient cells and tumor cells derived from LAM patients. In a xenograft model of
lymphangioleiomyomatosis presented by Dr. Yu at the 2008 LAM Research Meeting, estrogen
promoted the pulmonary metastases of tuberin-deficient ELT3 cells (TSC2-deficient rat
uterine leiomyoma cells) in female ovariectomized CB-17-scid mice, while the estrogen
inhibitor fulvestrant completely blocked estrogen-promoted pulmonary metastases. This work
was recently published.
Letrozole is a nonsteroidal aromatase inhibitor (inhibitor of estrogen synthesis)(14). It is
chemically described as 4,4'-(1H-1,2,4-Triazol-1-ylmethylene)diben-zonitrile.
In postmenopausal women, estrogens are mainly derived from the action of the aromatase
enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to
estrone and estradiol. The suppression of estrogen biosynthesis in peripheral tissues and in
the cancer tissue itself can therefore be achieved by specifically inhibiting the aromatase
enzyme.
Interventional
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment
The effect on Forced Expiratory Volume in one second
twelve months
No
Francis X McCormack, MD
Principal Investigator
University of Cincinnati
United States: Institutional Review Board
5708
NCT01353209
May 2011
Name | Location |
---|---|
University of Cincinnati | Cincinnati, Ohio 45267-0502 |