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