Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed transitional cell carcinoma of the bladder

- Stage IV disease

- Metastatic or locally advanced disease

- HER1- and/or HER2-positive disease, defined by the following criteria:

- 2+ or 3+ intensity on IHC

- Able to commence the study treatment within 10 weeks of completing chemotherapy

- Must have achieved objective response or stable disease following 4-8 courses of
first-line chemotherapy

- No progression with first-line chemotherapy for metastatic disease

- Any widely accepted chemotherapy regimen for bladder cancer allowed

- Patients who did not receive cisplatin are eligible

PATIENT CHARACTERISTICS:

- ECOG performance status 0-3

- ANC ≥ 1.0 x 10^9/L

- Hemoglobin ≥ 8.0 g/dL

- Platelet count ≥ 75 x 10^9/L

- ALT/AST < 2 times upper limit of normal (ULN)

- Bilirubin < 1.5 times ULN

- Serum creatinine ≤ 3.0 ULN AND/OR creatinine clearance ≥ 30 mL/min

- LVEF ≥ 50% (as assessed by quantitative echocardiogram or MUGA)

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No current active hepatic or biliary disease, except for any of the following:

- Gilbert's syndrome

- Asymptomatic gallstones

- Liver metastases

- Stable chronic liver disease per investigator assessment

- No known hypersensitivity to the study medication

- No history of prior or concurrent other neoplasms, except for:

- Any non life-threatening tumours that have been curatively treated.

- Prostate cancer isolated to the prostate gland

- No significant cardiac disease, including any of the following:

- Angina pectoris

- Severe cardiac arrhythmia requiring medication

- Severe conduction abnormalities

- Clinically significant valvular disease

- Cardiomegaly

- Prior myocardial infarction

- Ventricular hypertrophy

- Congestive heart failure

- Poorly uncontrolled hypertension (resting diastolic blood pressure > 115 mm Hg)

- Other cardiomyopathy

- No serious intercurrent medical or psychiatric illness

- No serious active infection

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No more than 1 line of prior chemotherapy for metastatic or locally advanced disease
(neoadjuvant/adjuvant chemotherapy allowed)

- No more than 10 weeks since first-line chemotherapy

- No prior lapatinib ditosylate

- No prior radiotherapy to the indicator lesion(s) (newly arising lesions in previously
irradiated areas allowed)

- At least 14 days since prior and no concurrent CYP3A4 inducers, including but not
limited to, any of the following:

- Antibiotics (all rifamycin class agents [e.g., rifampicin, rifabutin,
rifapentine])

- Anticonvulsants (phenytoin, carbamazepine, barbiturates [e.g., phenobarbital])

- Oral glucocorticoids (cortisone [> 50 mg], hydrocortisone [> 40 mg], prednisone
[> 10 mg], methylprednisolone [> 8 mg], dexamethasone [> 2 mg²])

- St. John's wort or modafinil

- At least 7 days since prior and no concurrent CYP3A4 inhibitors, including but not
limited to, any of the following:

- Antibiotics (clarithromycin, erythromycin, troleandomycin)

- Antifungals (itraconazole, ketoconazole, fluconazole [>150 mg daily],
voriconazole)

- Antiretrovirals/protease inhibitors (delavirdine, nelfinavir, amprenavir,
ritonavir, indinavir, saquinavir, lopinavir)

- Calcium channel blockers (verapamil, diltiazem)

- Antidepressants (nefazodone, fluvoxamine)

- Gastrointestinal agents (cimetidine, aprepitant)

- Grapefruit, grapefruit juice

- At least 6 months since prior and no concurrent amiodarone

- No concurrent radical or curative therapy (radiotherapy or surgery) at the end of
first-line treatment (palliative radiotherapy allowed)

- No other concurrent experimental or investigational drugs

- No other concurrent anticancer treatment, including cytotoxic or specific immune
therapy