Loap P, Loirat D, Berger F, et al. - A monocentric prospective open-label Phase I dose-escalation trial, RADIOPARP, was conducted to assess the combination of breast radiotherapy and Olaparib in triple-negative breast cancer (TNBC) patients with inflammatory, locoregionally advanced or metastatic disease, or with residual disease following neoadjuvant chemotherapy. At increasing dose levels (50, 100, 150 or 200 mg twice a day [BID]), olaparib was orally administered in patients; radiotherapy comprised 50 Gy to the breast or chest wall with or without lymph node irradiation. Escalation of olaparib to 200 mg BID was done without dose-limiting toxicities. There were no treatment-related grade ≥3 toxicity at 1-year follow-up. No cardiac, pulmonary or digestive toxicity resulted from the treatment. Overall, a 1-year follow-up report of the RADIOPARP Phase I trial revealed that this combination therapy (olaparib with breast radiotherapy) showed an excellent toxicity profile with few low-grade adverse events.