Lorcaserin in Treating Chemotherapy-Induced Peripheral Neuropathy in Patients With Stage I-IV Gastrointestinal or Breast Cancer

Inclusion Criteria:

* Patient with known diagnosis of gastrointestinal (GI) cancer or breast cancer stages I-IV
* Prior exposure to paclitaxel or oxaliplatin within last 24 months
* Have symptomatic CIPN confirmed by self-report, as demonstrated by PRO measure, CIPN-20
* If a female subject is with child bearing potential, she must have a negative pregnancy test at screening
* Female subjects of child-bearing potential and men must agree to use adequate contraception prior to study entry, for the duration of study participation and for 3 months after completion of study treatment administration. Adequate contraception includes methods such as oral contraceptives, double barrier method (condom plus spermicide or diaphragm), or abstaining from sexual intercourse
* Be willing and able to understand and sign the written informed consent document

Exclusion Criteria:

* Is beyond 24 months out from completion of oxaliplatin or paclitaxel
* Is asymptomatic for CIPN
* Is currently pregnant or breast feeding as there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with lorcaserin
* Has any other medical or psychiatric condition that in the opinion of the investigator would make the study therapy unsafe for the patient