Keytruda first-line treatment for triple negative breast cancer reached the primary end point of phase III

Wen Holly On February 12, MSD announced that its PD-1 inhibitor keytruda (pembrolizumab) combined with chemotherapy reached the primary end point of progression free survival (PFS) in the key phase 3 keynote-355 study of patients with metastatic triple negative breast cancer (mtnbc) expressing PD-L1 (combined positive score [CPS] ≥ 10) in the first-line treatment Keynote-355 is a randomized, three-stage clinical study (nct02819518) that evaluated the efficacy and safety of keytruda combined chemotherapy (one of three regimens, i The study consisted of two parts The first part was open label The safety and tolerance of keytruda combined chemotherapy were evaluated in 30 patients The second part is a double-blind study involving 847 patients The double primary end points of OS and PFS were evaluated in all subjects and those with tumor expression of PD-L1 (CPS ≥ 1 and CPS ≥ 10) The secondary end points included objective response rate (ORR), duration of response (DOR), disease control rate (DCR) and safety According to the mid-term analysis conducted by the independent data monitoring committee (DMC), keytruda combined chemotherapy as a first-line treatment, compared with chemotherapy alone, PFS achieved significant improvement in statistical and clinical significance Based on DMC recommendations, the study will continue to evaluate another overall survival (OS) primary endpoint In addition, the safety of keytruda in this study is consistent with the previously reported study, and no new safety signal is found He said he would communicate with regulators about the data from the trial and looked forward to sharing the results at the upcoming medical conference Breast cancer is the first high risk cancer in women, and the incidence rate is increasing year by year With the development of early screening technology and comprehensive treatment technology, the treatment of breast cancer has been significantly improved But one of the subtypes, triple negative breast cancer (TNBC), still has the problems of poor prognosis, high recurrence rate and low survival rate TNBC refers to breast cancer types with negative estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2), which accounts for 10% - 20% of all breast cancer pathological types The lack of all three receptors means that endocrine therapy and targeted therapy are ineffective for these receptors, so surgery-assisted radiotherapy and chemotherapy are still the main means to treat TNBC At present, Roche's tecentriq is the only tumor immunotherapy approved for the treatment of TNBC However, keytruda's series of clinical data on TNBC seems to be expected to change this situation According to the relevant data of keytruda treatment of TNBC released in September 2019, 64.8% of TNBC patients in keytruda + chemotherapy group achieved complete pathological remission, and 51.2% in chemical group alone In December 2019, MSD published a subgroup analysis data from a phase 3 clinical study (keynote-522) The results showed that 64.8% of TNBC patients in keytruda + chemotherapy group achieved complete pathological response, while 44.1% of TNBC patients in chemotherapy group achieved complete pathological response In addition, the keynote-522 study also showed that patients receiving keytruda chemotherapy had a 37% reduction in the risk of postoperative recurrence compared to patients receiving chemotherapy alone, although this result was not statistically significant.