['small cell lung cancer']
['anlotinib', 'placebo']

        Inclusion Criteria:

          -  Histological documentation of small cell lung cancer

          -  Advanced small cell lung cancer who had at least two chemotherapy regimens,at least
             one measurable lesion (by RECIST1.1)

          -  18-75 years,ECOG PS:0-2,Life expectancy of more than 3 months

          -  Main organs function is normal

          -  Women of childbearing potential should agree to use and utilize an adequate method of
             contraception (such as intrauterine device，contraceptive and condom) throughout
             treatment and for at least 6 months after study is stopped；the result of serum or
             urine pregnancy test should be negative within 7 days prior to study enrollment，and
             the patients required to be non-lactating；Man participants should agree to use and
             utilize an adequate method of contraception throughout treatment and for at least 6
             months after study is stopped

          -  Patients should participate in the study voluntarily and sign informed consent

        Exclusion Criteria:

          -  Patients who have been used anlotinib

          -  Patients who have been used targeted drugs(such as
             sunitinib,bevacizumab,endostar),Immune targeted drugs

          -  4 weeks or less from the last cytotoxic therapy, radiation therapy or surgery

          -  Patients whose primary lesion with active bleeding within 4 months

          -  Carcinomatous meningitis

          -  Patients who known to the central nervous system

          -  Patients with factors that could affect oral medication (such as dysphagia，chronic
             diarrhea, intestinal obstruction etc.)

          -  Patients with any severe and/or unable to control diseases，including：

               1. Blood pressure unable to be controlled ideally(systolic pressure≥150
                  mmHg，diastolic pressure≥100 mmHg);

               2. Patients with Grade 1 or higher myocardial ischemia, myocardial infarction or
                  malignant arrhythmias(including QTc≥450ms(male),QTc≥470ms（female）) and patients
                  with Grade 1 or higher congestive heart failure (NYHA Classification);

               3. Patients with active or unable to control serious infections;

               4. Patients with cirrhosis, decompensated liver disease, or active hepatitis;

               5. Patients with poorly controlled diabetes (fasting blood glucose(FBG)>10mmol/L)

               6. Urine protein ≥ ++，and 24-hour urinary protein excretion>1.0 g confirmed;

          -  Patients with non-healing wounds or fractures

          -  Patients with arterial or venous thromboembolic events occurred within 6 months, such
             as cerebrovascular accident (including transient ischemic attack), deep vein
             thrombosis and pulmonary embolism

          -  Patients with drug abuse history and unable to get rid of or Patients with mental
             disorders

          -  Imaging showed tumors have involved important blood vessels or by investigators
             determine likely during the follow-up study and cause fatal hemorrhage

          -  History of immunodeficiency

          -  Patients with concomitant diseases which could seriously endanger their own safety or
             could affect completion of the study according to investigators' judgment
      