RATIONALE: Monoclonal antibodies such as trastuzumab can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells. Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining trastuzumab with R115777 may kill more tumor cells.

PURPOSE: Phase I trial to study the effectiveness of trastuzumab plus R115777 in treating patients who have advanced or metastatic cancer.

OBJECTIVES: I. Determine the maximum tolerated dose of R115777 when administered with trastuzumab (Herceptin) in patients with advanced or metastatic adenocarcinoma. II. Assess the toxicities and pharmacokinetics of this treatment regimen in this patient population. III. Determine the antitumor activity of this treatment regimen in these patients. IV. Determine the relative biologic endpoints of this regimen and correlate them with toxicity and pharmacokinetic parameters in these patients.

OUTLINE: This is a dose escalation, multicenter study of R115777. Patients receive trastuzumab (Herceptin) IV over 90 minutes on days 1, 8, 15, and 22 plus oral R115777 twice daily for 3 weeks. Treatment continues every 28 days in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of R115777 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose at which no more than 1 of 6 patients experiences dose limiting toxicities. Patients are followed every 30 days until toxicity resolves.

PROJECTED ACCRUAL: A total of 3-24 patients will be accrued for this study over 24 months.

• Biological: trastuzumab
• Drug: tipifarnib

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed advanced or metastatic adenocarcinoma Expression of +1 to 3+ HER2/neu on immunohistochemical or immunocytochemistry staining No brain metastases unless all of the following is true Previously treated Asymptomatic Stable dose of decadron No evidence of edema Hormonal receptor status: Not specified

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Hepatic: Bilirubin no greater than 1.5 mg/dL AST/ALT no greater than 3 times upper limit of normal (ULN) (no greater than 5 times ULN in case of liver involvement) Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: LVEF at least 50% by RVG or MUGA No uncontrolled unstable angina No history of congestive heart failure or cardiac ischemia Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent active infection or serious systemic disorder that would preclude study No allergies to imidazole compounds

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior trastuzumab (Herceptin) No other concurrent immunotherapy Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks since mitomycin or nitrosoureas) and recovered No other concurrent chemotherapy Endocrine therapy: No concurrent hormonal cancer therapy except LHRH agonists for prostate cancer Radiotherapy: No concurrent radiotherapy Surgery: Not specified Other: No other concurrent experimental medications