Patient description: The patient is a 31-year-old woman complaining of abdominal pain. The pain started last night as diffuse abdominal discomfort. She had poor appetite as well as malaise. The pain worsened in intensity and became sharp in the morning. The pain became localized to the right lower quadrant in the morning. The temperature is within the normal limits with normal vital signs. Focal tenderness and guarding were observed during palpation of the right lower quadrant. Palpation of the left lower quadrant causes pain on the right. Her lab work is remarkable for leukocytosis. Computed Tomography of the abdomen with contrast shows the presence of a distended appendix with thickened appendiceal wall without perforation, abscess or gangrene. She is a candidate for laparoscopic appendectomy under general anesthesia.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Urothelial Bladder Cancer Gastric Adenocarcinoma Gastro-oesophageal Adenocarcinoma Head and Neck Cancer Biliary Tract Cancer Platinum-sensitive Urothelial Bladder Cancer Clear Cell Renal Cell Carcinoma Age ≥ 18 years Patients must have histologically or cytologically confirmed progressive metastatic or recurrent solid tumor (as defined below for each tumor type). Diagnosis must be stated in a pathology report and confirmed by the physician investigator Evidence of disease progression prior to trial entry To be enrolled in this study, only the tumor types and settings described below are allowed: 4.1 Cohorts 1 A-E: DNA repair deficiency, defined as bi-allelic loss-of-function alteration (mutation and/or deletion) in at least one of the following genes: ARID1A, ARID2, ATM, BARD1, BRCA1, BRCA2, BRIP1, CDK12, CHEK2, FANCA, IDH1, IDH2, NBN, PALB2, PBRM1, RAD51C, RAD51D, FANCA, NBN, RAD51, RAD54L, 4.1.1 Cohort 1A: Urothelial Bladder Cancer Patients must have received at least one line of prior platinum based systemic therapy. No more than 3 lines of previous systemic therapy for metastatic disease are allowed Relapse within 6 months of completion of adjuvant/neoadjuvant chemotherapy containing platinum-based regimen is considered as first-line therapy Previous adjuvant/neoadjuvant chemotherapy is allowed, if completed more than 6 months prior to starting the first-line therapy  Participation in another clinical study with an investigational product simultaneously and/or during the last 4 weeks (excepting observational or non-interventional clinical studies). 2. Receipt of the last dose of anti-cancer therapy (chemotherapy, immunotherapy, endocrine therapy, targeted therapy, biologic therapy, tumor embolization, monoclonal antibodies, other investigational agent) 28 days prior to the first dose of study drug, or five half lives of the previous agent, whichever is the shorter. 3. Participant has had radiation therapy encompassing >20% of the bone marrow within 2 weeks prior to Cycle 0 Day 1; or any radiation therapy within 1 week prior to Cycle 0 Day 1. 4. History of another primary malignancy within 5 years prior to Cycle 0 Day 1 except for Malignancy treated with curative intent and with no known active disease ≥5 years before the first dose of study drug and of low potential risk for recurrence Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease Adequately treated carcinoma in situ without evidence of disease (eg, carcinoma in situ of the cervix, localized prostate cancer treated surgically with curative intent, ductal carcinoma in situ treated surgically with curative intent). 5. Treatment with systemic corticosteroids or other immunosuppressive medications (including but not limited to prednisone, dexamethasone, cyclophosphamide, azathioprine, methotrexate, thalidomide, and antitumor necrosis factor agents) within 2 weeks prior to Cycle 0 Day 1, or anticipated requirements for systemic immunosuppressive medications during the trial: o The use of inhaled corticosteroids for chronic obstructive pulmonary disease, mineralocorticoids for patients with orthostatic hypotension, low-dose supplemental corticosteroids for adrenocortical insufficiency and topical steroids for cutaneous diseases are allowed. 6. Acute toxicities from previous therapies that have not resolved to Grade ≤ 1, with the exception of alopecia. 7. Any prior Grade ≥3 immune-related adverse event (irAE) while receiving any previous immunotherapy agent, or any unresolved irAE > Grade 1. 8. Participant must not have received a platelet transfusion ≤ 4 weeks prior to Cycle 0 Day 1. 9. Participants must not have received colony stimulating factors (eg, granulocyte colony-stimulating factor, granulocyte macrophage colony stimulating factor, or recombinant erythropoietin) within 4 weeks prior to Cycle 0 Day 1. 10. Participant has had any known Grade 3 or 4 anemia, neutropenia or thrombocytopenia due to prior chemotherapy that persisted > 4 weeks and was related to the most recent treatment. 11. Participant must not have any known history of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). 12. History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins. 13. Known hypersensitivity or allergy to biopharmaceuticals produced in Chinese hamster ovary cells or to any component of the TSR-042 formulation, or to niraparib or its components. 14. History of autoimmune disease, including but not limited to myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, vascular thrombosis associated with anti-phospholipid syndrome, Wegener's granulomatosis, Sjögren's syndrome, Guillain-Barré syndrome, multiple sclerosis, vasculitis or glomerulonephritis Patients with autoimmune hypothyroidism on a stable dose of thyroid replacement hormone are eligible Patients with controlled Type 1 diabetes mellitus on a stable insulin regimen are eligible. 15. Active or prior documented inflammatory bowel disease (e.g. Crohn's disease, ulcerative colitis). 16. History of interstitial lung disease, idiopathic pulmonary fibrosis, drug-induced pneumonitis, organizing pneumonia or evidence of active pneumonitis on screening chest CT scan. 17. History of allogeneic organ transplant or prior bone marrow transplantation of double umbilical cord blood transplantation. 18. Uncontrolled intercurrent illness including, but not limited to ongoing or active infection or severe infection requiring hospitalization or IV antibiotics within 2 weeks of starting treatment (with the exception of prophylactic antibiotics) symptomatic congestive heart failure > NYHA II, superior vena cava syndrome, uncontrolled hypertension, unstable angina pectoris, cardiac arrhythmia, pericardial effusion, myocardial infarction within 90 days active peptic ulcer disease or gastritis active bleeding diatheses