Table 2 Detailed Inclusion and Exclusion criteria

Each patient must meet all of the following inclusion criteria to be enrolled in the study:

• 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 0–1+, or 2+ if FISH-test is negative, 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• Signed informed consent prior to any study-specific procedure, with the understanding that consent may be withdrawn at any time without prejudice to future medical care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

• Women of childbearing potential must have a negative pregnancy test at screening and agree to practice 2 effective methods of contraception, at the same time, from the time of signing the informed consent form through 90 days after the last dose of study drug OR agree to practice true abstinence when this is in line with the preferred and usual lifestyle of the subject (Periodic abstinence [eg, calendar, ovulation, symptothermal, post-ovulation methods] and withdrawal are not acceptable methods of contraception.

• 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:

Hematologic:

ANC (absolute neutrophil count) ≥ 1.5 × 109/L

Hemoglobin ≥8 g/dL

Platelets ≥100 × 109/L

Liver Function:

Albumin ≥2.5 g/dL

Serum bilirubin ≤2 mg/dL

AST and ALT ≤3 x ULN without liver metastases and ≤ 5 x ULN with documented liver metastases

Renal Function:

Serum creatinin ≤1.5 mg/dL or calculated creatinin clearance ≥50

Patients meeting any of the following exclusion criteria are not to be enrolled in the study.

• 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 HIV 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