Study of Paclitaxel in Combination With BOS172722 in Patients With Advanced Nonhaematologic Malignancies

Inclusion Criteria: Participants are eligible to be included in the study only if all of the following criteria apply: * For Part A only, histopathologically confirmed diagnosis of an advanced nonhaematologic malignancy * For Part B only, histopathologically confirmed diagnosis of triple-negative breast cancer * No standard curative treatment or has declined standard therapy * Eastern Cooperative Oncology Group performance status 0 or 1, measured within 72 hours before the first BOS172722 or paclitaxel dose * Predicted life expectancy of ≥ 3 months * Adequate renal function (creatinine ≤ 1.5 × upper limit of normal \[ULN\] or glomerular filtration rate ≥ 50 milliliters per minute \[mL/min\]) * Adequate hepatic function: * Total bilirubin ≤ 1.5 × ULN * Aspartate transaminase ≤ 3 × ULN (or ≤ 5 × ULN if due to liver involvement by tumor) * Alanine transaminase ≤ 3 × ULN (or ≤ 5 × ULN if due to liver involvement by tumor) * Adequate bone marrow function: * Hemoglobin ≥ 9.0 grams per deciliter (g/dL) * Platelet count ≥ 100 × 10\^9 cells per liter (cells/L) * Absolute neutrophil count ≥ 1.5 × 10\^9 cells/L * Mean corrected QT interval as calculated by the Fridericia correction formula \< 470 milliseconds * Willingness to use adequate contraceptive methods * Capable of giving signed informed consent * Willingness to avoid direct sunlight and the use of tanning equipment during the study and for at least 30 days after the last BOS172722 dose Exclusion Criteria: Part…