RATIONALE: Monoclonal antibodies, such as trastuzumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them.

PURPOSE: This phase II trial is studying how well trastuzumab works in treating patients with metastatic or recurrent salivary gland cancer.

OBJECTIVES:

• Determine the response (confirmed and unconfirmed, complete and partial) in patients with metastatic or recurrent high-grade salivary gland carcinoma treated with trastuzumab (Herceptin ®).
• Determine 1-year progression-free and overall survival of patients treated with this drug.
• Determine the toxic effects of this drug in these patients.
• Correlate, preliminarily, the indicators of C-erb B2 oncoprotein expression, C-erb B2 oncogene amplification, and epidermal growth factor receptor expression with response and progression-free and overall survival of patients treated with this drug.

OUTLINE: Patients receive trastuzumab (Herceptin ®) IV over 30-90 minutes on days 1, 8, 15, and 22. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed every 8 weeks until disease progression and then every 3 months for 1 year and every 6 months until 3 years from study entry.

PROJECTED ACCRUAL: A total of 20-35 patients will be accrued for this study within 10-18 months.

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed high-grade (poorly differentiated or undifferentiated) salivary gland carcinoma, including any of the following histological subtypes:
• Adenocarcinoma
• Acinic cell carcinoma
• Mucoepidermoid carcinoma
• Salivary duct carcinoma
• Undifferentiated carcinoma
• Metastatic or recurrent disease
• Not amenable to salvage surgical resection or radiotherapy
• Tumors must demonstrate HER2/neu gene amplification by fluorescence in situ hybridization (FISH) OR overexpression of HER2/neu protein ( 2+ or 3+) by immunohistochemistry
• Measurable disease
• No adenoid cystic carcinoma
• No known brain metastases

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Zubrod 0-2

Life expectancy

• Not specified

Hematopoietic

• WBC ≥ 2,000/mm^3
• Absolute neutrophil count ≥ 1,000/mm^3
• Platelet count ≥ 75,000/mm^3

Hepatic

• Bilirubin ≤ 2.5 times upper limit of normal (ULN) (5 times ULN if liver metastases are present)
• AST and ALT ≤ 2.5 times ULN (5 times ULN if liver metastases are present)

Renal

• Creatinine < 2.5 times ULN

Other

• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 6 months after completion of study treatment
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or adequately treated stage I or II cancer in complete remission
• No history of allergic reaction to compounds of similar chemical or biological composition to trastuzumab

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent filgrastim (G-CSF)

Chemotherapy

• At least 4 weeks since prior chemotherapy and recovered
• No concurrent chemotherapy

Endocrine therapy

• No concurrent hormonal therapy except steroids for emesis, adrenal failure, or septic shock or hormones for non-disease-related conditions (e.g., insulin for diabetes)

Radiotherapy

• At least 4 weeks since prior radiotherapy and recovered
• No concurrent radiotherapy

Surgery

• At least 4 weeks since prior surgery and recovered

Other

• No other concurrent investigational agents