Inclusion criteria:

        Diagnosis of CA6-positive solid tumors as moderate to intense membrane staining of ≥15% of
        tumor cells for which no standard therapy is available.

        Exclusion criteria:

          -  Eastem Cooperative Oncology Group performance status ≥2.

          -  Any serious active disease or co-morbid condition, which, in the opinion of the
             Investigator, may interfere with the safety or the compliance with the study.

          -  Poor bone marrow reserve.

          -  Poor liver and renal function.

          -  Pregnant or breast-feeding woman.

          -  No use of effective birth control methods, when applicable.

          -  No resolution of all specific toxicities (excluding alopecia) related to any prior
             anti-cancer therapy to Grade ≤1 according to the National Cancer Institute - Common
             Toxicity Criteria for Adverse Events (NCI-CTCAE) version 4.03 grade scaling.

          -  Wash out period of less than 3 weeks from previous antitumor therapy or any
             investigational treatment, (and less than 6 weeks in case of prior nitroso-urea and or
             mitomycin C treatment). Patients will be eligible if hormonotherapy (ie, for breast
             tumors) is discontinued before first Investigational product administration.

          -  Wash out period of less than 1 week from last palliative dose of radiotherapy.

          -  Patients with respiratory insufficiency defined by a decrease more than 50% compared
             to theoretical baseline pulmonary volumes and theoretical baseline Diffusing capacity
             of the Lung for Carbon monoxyde.

          -  Any lung radiotherapy in patient's cancer history.

          -  Patients with previous history or active interstitial lung disease or pulmonary
             fibrosis.

          -  Patients with abnormal cardiac function defined by a Left Ventricular Ejection
             Fraction <50%.

          -  Patients with previous history of acute cardiac failure.

          -  Patients with previous history and/or unresolved corneal disorders.

          -  Known intolerance to infused protein products or maytansinoids.

          -  Patients treated with strong CYP3A inhibitors within 2 weeks prior study drug
             administration.

          -  For patients to be treated in the midazolam cohort:

          -  Any treatment known to induce CYP3A isoenzymes or to inhibit CYP3A4 activities not
             allowed within 2 weeks before midazolam administration and up to the end of
             pharmacokinetic sampling following the last midazolam administration.

          -  Any contra-indications to midazolam, according to the applicable labeling.

          -  Patients older than 60 years.

        The above information is not intended to contain all considerations relevant to a patient's
        potential participation in a clinical trial.