A Phase I, Open-Label, 2 Part Multicentre Study to Assess the Safety, Tolerability and Efficacy of Olaparib in Combination With Carboplatin: Part A: Dose Escalation of Olaparib in Combination With Carboplatin in Patients With Advanced HER-2 Negative Breast Cancer; Followed by Part B: an Expansion Phase of Olaparib in Combination With Carboplatin in the Neoadjuvant Treatment of HER-2 Negative Breast Cancer Patients With Germline BRCA1/2 Mutations

In Part A up to 36 evaluable patients with advanced breast cancer will be enrolled across 6 cohorts. The total number of patients will depend on the number of dose escalations necessary to enable a decision to be made on the recommended dose to take forward into Part B of the study.

The planned dose escalation will start with cohort 1, where patients will receive carboplatin (AUC5) on day 1 of cycle 1, and will start dosing with olaparib tablets at the dose of 50 mg twice daily (bd) on day 4 until day 19 of cycle 1 inclusive (a total of 16 days per cycle). Patients will receive carboplatin on day 1 of each 3 weeks cycle in combination with olaparib for a total of 4 cycles. Provided that there are no safety concerns after assessment of 6 evaluable patients in the first cohort, patients in subsequent cohorts may be dosed following Safety Review Committee (SRC) approval. Dose escalation scheme may be adjusted during the study on the basis of emerging safety, efficacy and pharmacokinetic data. Those patients in Part A who tolerate the combination up to and including cycle 4 may remain on treatment, either continuing with the combination, with carboplatin alone at the same AUC or with olaparib alone at the dose of 300 mg bd, if in the opinion of the treating Investigator, a patient is deemed to be deriving clinical benefit from treatment. In these cases, a patient may remain on treatment until progression, unacceptable toxicity or until other discontinuation criteria are met. Beyond cycle 4, patients will undergo assessments in line with the clinical protocol. Once the maximum tolerated dose (MTD) and/or recommended dose (RD) has been defined in Part A, a dose expansion phase, Part B will begin and this will include up to 21 patients with HER2 negative breast cancer, with a deleterious or suspected deleterious germlineBRCA1/2 (gBRCA1/2) mutation, who are deemed eligible for neoadjuvant therapy.

Part B will explore the safety, tolerability and efficacy of the combination of olaparib and carboplatin in terms of pathological complete response (pCR) rate. Neoadjuvant systemic therapy will consist of the following anti-cancer drugs for a total of 8 cycles of treatment:

• The first 4 cycles (cycle 1 to cycle 4: 12 weeks) will be based on combination of olaparib, at the defined RD and schedule from Part A, with carboplatin. It is expected that a cycle of treatment would be 3 weeks.
• Another 4 cycles (cycle 5 to cycle 8) will be based on a combination of an anthracycline and cyclophosphamide (AC). The choice of the AC regimen will be up to local Investigator following international guidelines (National Comprehensive Cancer Network (NCCN), European Society for Medical Oncology (ESMO), and St Gallen).

The tumour response will be assessed through careful clinical examination and also with radiological examinations between cycle 4 and 5 and at the end of neoadjuvant part, before surgery. Additionally, tumour biopsy will be performed within 7 days before cycle 5 day 1, after completion of carboplatin and olaparib combination therapy and early pathological response assessed by local pathologist. Curative-intent surgery should be performed following completion of neoadjuvant treatment in all patients, 3 to 5 weeks after day 1 of the last cycle of neoadjuvant treatment.