Cobimetinib and Atezolizumab in Treating Participants With Advanced or Refractory Rare Tumors

Inclusion Criteria

• Patients must be informed of the investigational nature of this study and must be willing to give written informed consent in accordance with institutional and federal guidelines. Patients must be able to comply with the requirements and assessments of the study protocol
• Must have histologically or cytologically documented rare tumor as defined per protocol that is metastatic or locally advanced and unresectable. Patients with locally advanced cutaneous squamous cell carcinoma that are technically resectable but in whom surgery is expected to lead to substantial function impairment or disfigurement are eligible
• Must be refractory or intolerant to standard lines of therapy
• Must have completed prior chemotherapy, immunotherapy, or radiation therapy at least 14 days prior to start of treatment and all toxicity must be resolved to Common Terminology Criteria for Adverse Events (CTCAE) v4.0 grade 1 (with the exception of CTCAE v4.0 grade 2 neuropathy) prior to start of treatment
• Presence of radiographically evaluable disease
• Eastern Cooperative Oncology Group (ECOG) performance status of = = 1,000/mcL (obtained within 14 days prior to enrollment)
• Platelets >= 75, 000/mcL (obtained within 14 days prior to enrollment)
• Hemoglobin >= 9 g/dL (obtained within 14 days prior to enrollment)
• Calculated creatinine clearance > 30 ml/min (obtained within 14 days prior to enrollment)
• Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) = = 1 year
• Fertile men and women must use an effective method of contraception during treatment and for at least 6 months after completion of treatment as directed by their physician. Effective methods of contraception are defined as those that result in a low failure rate (i.e., less than 1% per year) when used consistently and correctly (e.g., implants, injectables, combined oral contraception or intra-uterine devices). At the discretion of the Investigator, acceptable methods of contraception may include total abstinence in cases where the lifestyle of the patient ensures compliance. (Periodic abstinence [e.g., calendar, ovulation, symptothermal, post ovulation methods] and withdrawal are not acceptable methods of contraception)
• For individual baskets:
• Appendiceal adenocarcinoma
• Not considered candidate for curative surgery
• Cutaneous squamous cell carcinoma
• Patients with either metastatic or locally advanced cutaneous squamous cell carcinoma that are technically resectable but in whom surgery is expected to lead to substantial function impairment or disfigurement are eligible
• Small bowel adenocarcinoma
• Must be refractory or intolerant to at least one line of fluorouracil (5FU)-based chemotherapy for metastatic disease

Exclusion Criteria

• Presence of brain metastases (unless they have been adequately treated with radiotherapy or surgery and stable for at least 30 days prior to enrollment provided patient is neurologically asymptomatic and without corticosteroid treatment for at least 7 days prior to enrollment)
• Uncontrolled intercurrent illness including, but not limited to diabetes, hypertension, severe infection, severe malnutrition, unstable angina, class III-IV New York Heart Association (NYHA) congestive heart failure, ventricular arrhythmias, active ischemic heart disease, or myocardial infarction within 6 months prior to enrollment
• History of or evidence of retinal pathology on ophthalmologic examination that is considered a risk factor for neurosensory retinal detachment, central serous chorioretinopathy, retinal vein occlusion (RVO), or neovascular macular degeneration
• Patients will be excluded from study participation if they currently are known to have any of the following risk factors for RVO: a. Glaucoma with intraocular pressure >= 21 mmHg b. Grade >= 2 serum cholesterol c. Grade >= 2 hypertriglyceridemia d. Grade >= 2 or symptomatic hyperglycemia (fasting) e. Grade >= 2 uncontrolled hy