A Multicenter Phase II Pilot Open Label

Inclusion Criteria: 1. Histologically confirmed differentiated follicular or poorly differentiated thyroid cancer 2. Patients refractory to radio iodine: i.e.; absence of radioiodine uptake in at least one target lesion on a post-therapeutic whole body scan, presence of a target lesion after a cumulative radio-iodine activity of at least 600 mCi, patients with radio-iodine uptake who have progression of the disease within 12 months after radioactive iodine (RAI) treatment 3. Metastatic or locally invasive disease 4. Patients must have at least one site of measurable disease per RECIST (version 1.1.) 5. Documented progression as per RECIST (version 1.1.) based on 2 comparative imagings performed within the last 12 months (+20%) 6. Patients may have received two previous treatment with tyrosine kinase inhibitors but must be off treatment within at least 4 weeks 7. Patient has signed the informed consent before any trial related activities and according to local guidelines 8. Patient (male or female) is ≥ 18 years at the day of consenting to the study 9. Patient has an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 which the investigator believes is stable at the time of screening 10. Patient has adequate bone marrow and organ function as defined by the following laboratory values: * Absolute Neutrophil Count (ANC) ≥ 1.0 x 109/L * Platelets ≥ 100 x 109/L * Hemoglobin ≥ 9.0 g/dL * INR ≤ 1,5 * Potassium, calcium,and magnesium within normal limits (WNL) for theinstitution * Serum Creatinine ≤ 1.5 x ULN * Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) within normal range * Total Serum bilirubin within normal range normal liver function test results, and absence of other contributing disease processes at the time of diagnosis * Fasting plasma glucose (FPG) ≤ 120 mg/dL or ≤ 6.7 mmol/L * HbA1c ≤ 8 % 11. Patient has no legal protection measure 12. Patient has a health coverage Exclusion Criteria: 1. Other histological subtypes of thyroid tumors: papillary, anaplastic, medullary, lymphoma or sarcoma 2. Patient has received previous treatment with PI3K and/or mTOR inhibitors or AKT inhibitors, 3. Patient has symptomatic central nervous system (CNS) metastases. Patients with controlled and asymptomatic CNS metastases may participate in this trial. The patient must have completed any prior local treatment for CNS metastases ≥ 28 days (including radiotherapy and/or surgery) prior to enrollment in this study 4. Patient has a concurrent malignancy or malignancy within 3 years of study enrollment, 5. Patient has a score ≥ 12 on the PHQ-9 questionnaire 6. Patient selects a response of "1, 2 or 3" to question number 9 on the PHQ-9 questionnaire regarding potential for suicidal thoughts or ideation 7. Patient has a GAD-7 mood scale score ≥ 15 8. Patient has a medically documented history of or active major depressive episode, bipolar disorder (I or II), obsessive-compulsive disorder, schizophrenia, a history of suicidal attempt or ideation, or homicidal ideation 9. Patient is concurrently using other approved or investigational antineoplastic agent 10. Patient who received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation ≤ 2 weeks prior to starting study drug or who have not recovered to grade 1 or better from related side effects of such therapy 11. Patient has had major surgery within 14 days prior to starting study drug or has not recovered from major side effects of the surgery 12. Patient has active cardiac disease or a history of cardiac dysfunction including any of the following:Unstable angina pectoris within 6 months prior to study entry,Symptomatic pericarditis,Documented myocardial infarction within 6 months prior to study entry,History of documented congestive heart failure,Documented cardiomyopathy 13. Patient has a Left Ventricular Ejection Fraction (LVEF) \< 50% as determined by Multiple Gated acquisition (MUGA) scan or echocardiogram (ECHO) 14. Patient has any of the following cardiac conduction abnormalities: 15. Patient is currently receiving treatment with medication that has a known risk to prolong the QT interval or inducing Torsades de Pointes, and the treatment cannot be discontinued or switched to a different medication prior to randomization. 16. Patient has impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of BKM120 17. Patient is currently receiving increasing or chronic treatment (\> 5 days) with corticosteroids or another immunosuppressive agent, as chronic administration of corticosteroids (\> 5 days) can induce CYP3A4 The following uses of corticosteroids are permitted: single doses; topical applications, inhaled sprays, eye drops or local injections 18. Patient has any other concurrent severe and/or uncontrolled medical condition that would, in the investigator's judgment contraindicate patient participation in the clinical study 19. Patient has a history of non-compliance to medical regimen or inability to grant consent 20. Patient is currently receiving treatment with drugs known to be moderate and strong inhibitors or inducers of isoenzyme CYP3A, The patient must have discontinued strong inducers for at least one week and must have discontinued strong inhibitors before the treatment is initiated. Switching to a different medication prior to entry in the treatment phase is allowed. 21. Patient has a known history of HIV (testing not mandatory) infection 22. Pregnant or nursing (lactating) woman where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive beta hCG laboratory test (\> 5 mIU/mL) 23. Patient who does not apply highly effective contraception during the study and through the duration as defined below after the final dose of study treatment. 24. Patient has a known hypersensitivity to any of the excipients of BKM120 25. Patient has not recovered to grade 1 or better (except alopecia) from related side effects of any prior antineoplastic therapy 26. Patient is currently receiving warfarin or other coumarin derived anti-coagulant, for treatment, prophylaxis or otherwise. Therapy with heparin, low molecular weight heparin (LMWH), or fondaparinux is allowed