Inclusion Criteria:
DISEASE CHARACTERISTICS During Dose Escalation:
* Histologically or cytologically confirmed diagnosis of 1 of the following:
* Small cell lung cancer (SCLC)
* Other pulmonary tumors of neuroendocrine origin, including neuroendocrine carcinoma or non-SCLC with neuroendocrine features
* Non-pulmonary small cell carcinoma
* Metastatic carcinoid tumor
* Other CD56-positive solid tumor
* Diagnoses other than SCLC must have confirmation of tumor CD56 expression before study entry
* Relapsed or refractory disease
* Must have received at least 1 but no more than 3 prior chemotherapy regimens\* and recovered from any acute toxicities
* No prior chemotherapy for carcinoid or neuroendocrine tumors
DISEASE CHARACTERISTICS During MTD Expansion:
* Relapsed or refractory Small cell lung cancer (SCLC)
* Metastatic Merkel Cell carcinomas
* Ovarian carcinomas
At the MTD:
SCLC patients must have received one, but no more than 1 prior chemotherapy regimen Merkel and Ovarian patients must have received at least one prior chemotherapy regimen. Ovarian patients must have received at least one platinum-based regimen.
* Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan
* No uncontrolled carcinoid syndrome (e.g., flushing, uncontrolled diarrhea, labile blood pressure)
* No active brain metastases; no evidence of active disease and no requirement for anticonvulsant medications or steroids.
PATIENT CHARACTERISTICS:
* Life expectancy ≥ 3 months
* ECOG performance status 0-2
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* Absolute neutrophil count ≥ 1,500/mm\^3
* Platelet count ≥ 100,000/mm\^3
* Hemoglobin ≥ 10 g/dL
* Creatinine ≤ 1.5 times upper limit of normal (ULN)
* AST and ALT ≤ 2.5 times ULN
* Bilirubin ≤ 3 times ULN
* No rapidly rising liver function tests (LFTs)
* Pancreatic function, amylase and lipase within upper limit of normal.
* No significant residual neurological or cardiac toxicity ≥ grade 2 after prior chemotherapy
* No myocardial infarction within the past 6 months
* No unstable angina pectoris
* No uncontrolled congestive heart failure
* No uncontrolled arrhythmia
* No severe aortic stenosis
* No history of multiple sclerosis or other demyelinating disease
* No Eaton-Lambert syndrome (para-neoplastic syndrome)
* No history of hemorrhagic stroke
* No CNS injury with residual neurologic deficit
* No ischemic stroke within the past 6 months
* No history of pancreatitis
* No current active infection or history of recurrent infection with varicella-zoster virus (shingles) or cytomegalovirus
* No other concurrent serious infection
* No chronic alcoholism
* No other concurrent illness or condition that would interfere with study outcome
* No other malignancy within the past 3 years except adequately treated basal cell carcinoma of the skin or carcinoma in situ of the cervix
* No known recent biochemical or clinical evidence of pancreatitis or extensive metastatic disease involving the pancreas
PRIOR CONCURRENT THERAPY:
* See Disease Characteristics
* Total cumulative dosage of prior anthracycline treatment must not exceed threshold for cardiotoxicity
* No known hypersensitivity to previous monoclonal antibody therapy
* More than 4 weeks since prior and no concurrent chemotherapy or radiotherapy
* More than 4 weeks since prior and no other concurrent investigational agents
* At least 4 weeks since prior and no concurrent surgery
* No other concurrent antineoplastic treatment, including immunotherapy or steroid therapy