Inclusion Criteria:

          -  Metastatic or locally advanced (without curative loco-regional treatment options with
             curative intention) adenocarcinoma of the breast, histologically confirmed

          -  Triple-negative subtype defined as the absence of staining for estrogen receptor (IHC
             <1%), progesterone receptor (IHC <1%) and HER2/neu (IHC 1+ or ISH ratio of < 2.0
             between Her2 gene copy number and centromere of chromosome 17 or a copy number of 4 or
             less)

          -  Signed informed consent prior to any study-specific procedure, with the understanding
             that consent may be withdrawn at any time without prejudice to future medical care

          -  Female patients, age ≥ 18 years

          -  At least one prior line of chemotherapy for metastatic or locally advanced disease or
             disease progression within 12 months of completion of adjuvant chemotherapy

          -  Documented disease progression

          -  At least one measurable lesion according to RECIST 1.1 criteria

          -  Life expectancy of at least 12 weeks

          -  Performance status ECOG 0-2

          -  Adequate left ventricular ejection fraction at baseline, defined as LVEF ≥ 50% by
             either echocardiogram or MUGA

          -  Peripheral neuropathy NCI CTCAE grade ≤ 1 or grade 2 if no pain on clinical
             examination

          -  Adequate hematological, liver and renal function:

        Exclusion Criteria:

          -  Pregnant or lactating women

          -  Serious medical or psychiatric disorders that would interfere with the patient's
             safety or informed consent

          -  Clinically significant cardiovascular disease, requiring medication during the study
             and which might interfere with regularity of the study treatment, or not controlled by
             medication.

          -  Radiation of the target lesion within the last 4 weeks prior to randomization

          -  Prior radiation to ≥ 30% of bone marrow

          -  Active bacterial, viral or fungal infection

          -  Known HCV infection

          -  Patients with clinically apparent brain metastases or evidence of a spinal cord
             compression

          -  Major surgery within 14 days before enrollment

          -  Systemic treatment, within 14 days before the first dose of ixazomib, with strong
             CYP3A inducers (rifampin, rifapentine, rifabutin, carbamazepine, phenytoin,
             phenobarbital), or use of Ginkgo biloba or St. John's wort.

          -  Participation in other clinical trials, including those with other investigational
             agents not included in this trial, within 30 days of the start of this trial and
             throughout the duration of this trial

          -  Patients that have previously been treated with ixazomib, or participated in a study
             with ixazomib whether treated with ixazomib or not

          -  History of other malignancy; patients who have been disease-free for 5 years or
             patients with a history of completely resected non-melanoma skin cancer or
             successfully treated in situ carcinoma are eligible

          -  Prior treatment with a platinum derivative (except in (neo-)adjuvant setting if breast
             cancer recurrence did not occur within 12 months after (neo-)adjuvant chemotherapy
             completion) and/or with a proteasome inhibitor

          -  Known hypersensitivity to the study drugs