DISEASE CHARACTERISTICS:

• Histologically confirmed persistent or recurrent ovarian epithelial or primary peritoneal cancer

• Measurable disease

  • At least 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques OR ≥ 10 mm by spiral CT scan

  • Presence of ≥ 1 target lesion

    • Tumors within a previously irradiated field are not considered target lesions unless evidence of progression is documented or proven by biopsy 3 months after completion of radiotherapy

• Disease progression during OR persistent disease after 1 prior platinum-based chemotherapy regimen* for primary disease containing carboplatin, cisplatin, or another organoplatinum compound

  • Initial treatment may have included high-dose therapy, consolidation therapy, or extended therapy administered after surgical or non-surgical assessment
  • Treatment-free interval after platinum-based chemotherapy < 12 months NOTE: *One additional prior cytotoxic regimen for recurrent or persistent disease that occurred during or after platinum-based chemotherapy allowed
• Tumor accessible by guided core needle or fine needle biopsy
• Ineligible for any higher priority Gynecologic Oncology Group protocols (i.e., any active phase III protocol for the same patient population)

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• GOG 0-2 (patients who have received 1 prior treatment regimen)
• GOG 0-1 (patients who have received 2 prior treatment regimens)

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3

Hepatic

• Bilirubin ≤ 1.5 times upper limit of normal (ULN)
• SGOT ≤ 2.5 times ULN
• Alkaline phosphatase ≤ 2.5 times ULN

Renal

• Creatinine ≤ 1.5 times ULN

Cardiovascular

• Ejection fraction normal by echocardiogram or MUGA

Gastrointestinal

• No GI disease resulting in an inability to take oral medication
• No malabsorption syndrome
• No requirement for IV alimentation
• No uncontrolled inflammatory GI disease (e.g., Crohn's disease or ulcerative colitis)

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for ≥ 1 month after completion of study treatment
• No active infection requiring antibiotics
• No sensory or motor neuropathy > grade 1
• No other invasive malignancy within the past 5 years except nonmelanoma skin cancer
• No history of allergic reaction attributed to compounds of similar chemical or biological composition to lapatinib

PRIOR CONCURRENT THERAPY:

Biologic therapy

• At least 4 weeks since prior immunologic agents for the malignancy
• No prior trastuzumab (Herceptin®) or cetuximab

Chemotherapy

• See Disease Characteristics
• Recovered from prior chemotherapy
• At least 6 weeks since prior nitrosoureas or mitomycin for the malignancy
• No prior non-cytotoxic chemotherapy for recurrent or persistent disease

Endocrine therapy

• At least 2 weeks since prior and no concurrent dexamethasone or dexamethasone equivalent dose > 1.5 mg/day
• At least 1 week since prior hormonal therapy for the malignancy
• Concurrent hormone replacement therapy allowed

Radiotherapy

• See Disease Characteristics
• Recovered from prior radiotherapy
• No prior radiotherapy to > 25% of marrow-bearing areas

Surgery

• See Disease Characteristics
• Recovered from prior surgery
• No prior surgical procedure affecting gastrointestinal (GI) absorption

Other

• At least 4 weeks since other prior therapy for the malignancy
• At least 6 months since prior and no concurrent amiodarone
• At least 1 week since other prior and no concurrent CYP3A4 inhibitors
• At least 2 weeks since prior and no concurrent CYP3A4 inducers

• At least 1 week since prior and no concurrent H2 inhibitors or proton pump inhibitors

  • Concurrent antacids allowed provided they are not administered within 1 hour before and 1 hour after study drug administration
• No prior cancer treatment that would preclude study treatment
• No prior lapatinib
• No other prior target-specific therapy directed to the HER family (e.g., gefitinib or erlotinib)
• No concurrent herbal medications
• No concurrent combination antiretroviral therapy for HIV-positive patients