Gabapentin With or Without Antidepressants in Treating Hot Flashes in Women Who Have Had Breast Cancer or Have Concerns About Taking Hormone Therapy

OBJECTIVES:

- Compare the efficacy of gabapentin with vs without an antidepressant, as measured by
the frequency and intensity of hot flashes, in patients with a history of breast cancer
or a concern about taking hormonal therapy due to a fear of developing breast cancer.

- Compare adverse events in patients treated with these regimens.

- Correlate a reduction in hot flash scores with improvement in quality of life and
related outcomes in patients treated with these regimens.

OUTLINE: This is a randomized, multicenter study. Patients are stratified according to
duration of hot flash symptoms (< 9 months vs ≥ 9 months), average frequency of hot flashes
per day (2-3 vs 4-9 vs ≥ 10), and antidepressant currently being used (venlafaxine vs
paroxetine vs other). Patients are randomized to 1 of 2 treatment arms.

- Arm I: Patients continue to receive the same antidepressant (as before study entry) on
weeks 1-5. During weeks 2-5, patients also receive oral gabapentin once daily on days
8-10, twice daily on days 11-13, and then three times daily on days 14-35 in the
absence of unacceptable toxicity.

- Arm II: Patients receive gabapentin as in arm I. Patients are tapered off their
antidepressant over 7-10 days and remain on gabapentin alone (per arm I schedule).

Patients in both arms complete a hot flash diary at baseline and then daily during study
treatment.

Quality of life is assessed at baseline and then weekly during study treatment.

PROJECTED ACCRUAL: A total of 110 patients (55 per treatment arm) will be accrued for this
study within 2 years.

DISEASE CHARACTERISTICS:

- History of breast cancer OR a concern about taking hormonal therapy due to a fear of
developing breast cancer

- Experiencing bothersome hot flashes, defined as patient-reported occurrence ≥ 14
times per week AND sufficiently severe to prompt desire for additional therapeutic
intervention despite current use of an antidepressant

- Currently (≥ 2 weeks) being treated with a stable dose of an antidepressant

- No monoamine oxidase inhibitors or tricyclics

- No current evidence of malignant disease

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age

- 18 and over

Sex

- Female

Performance status

- ECOG 0-1

Life expectancy

- At least 6 months

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier contraception

PRIOR CONCURRENT THERAPY:

Chemotherapy

- More than 4 weeks since prior antineoplastic chemotherapy

- No concurrent antineoplastic chemotherapy

Endocrine therapy

- More than 4 weeks since prior androgens, estrogens, or progestational agents

- More than 2 weeks since prior dehydroepiandrosterone (DHEA) for treatment of hot
flashes

- No concurrent androgens, estrogens, or progestational agents, including oral
contraceptives

- No concurrent DHEA for treatment of hot flashes

- Concurrent tamoxifen, raloxifene, or aromatase inhibitor therapy allowed if on a
stable dose for at least 4 weeks prior to study entry and during study treatment

Other

- No prior gabapentin

- More than 2 weeks since other prior treatment for hot flashes (e.g., clonidine or
Bellergal-S®)

- Concurrent vitamin E or soy supplements allowed if on a stable dose for at least 1
month prior to study entry and during study treatment

- No other concurrent treatment for hot flashes (e.g., clonidine or Bellergal-S®)

- No other concurrent antidepressants