As breast cancer awareness month progresses, the pink ribbons remind us of the ongoing fight to battle breast cancer. The focus is currently on developing targeted therapies aimed to treat specific forms of breast cancer. One example is triple-negative breast cancer (TNBC), which is defined as breast cancer that does not overexpress the estrogen receptor (ER), progesterone receptor (PR) or human epidermal growth factor receptor 2 (Her2) genes .
The TNBC market is expected to experience substantial growth over the next 10 years. TNBC represents 10-20% of breast cancer diagnoses, and Datamonitor Healthcare estimates that TNBC comprises 13.5% of all breast cancer diagnoses in the United States, 14.3% in the major European markets of France, Germany, Italy, Spain, and UK, and 12.9% in Japan. The current standard of care for TNBC in both the first and second line setting is chemotherapy with or without bevacizumab, and in metastatic settings, TNBC is associated with decreased survival rates. The lower survival rate and lack of targeted therapies provide opportunity for development of novel therapies in TNBC .
As of September 2016, there were a total of 771 ongoing industry sponsored phase I-III trials in breast cancer, 26% of which include TNBC patients (204 trials). Over 43% (89/204) of these trials are exclusively studying breast cancer and do not include any additional disease types (Figure 1). Stage IV (metastatic) TNBC patients appear to be the primary target as they are included in 73% (65/89) of these breast cancer only trials. In addition to the ongoing activity, there are a total of 36 industry sponsored trials (25 in breast cancer only) that are planned to enroll TNBC patients.
More than 75% of the ongoing trials that include TNBC patients have trial locations in the United States. The major European markets (France, Germany, Italy, Spain, and UK) are included in over 85% of these ongoing trials (Figure 2). Figure 3 illustrates the top 15 industry sponsors and collaborators of trials that include TNBC patients. Roche leads with the largest number of ongoing trials, most of which evaluate Roche’s PD-L1 antagonist, atezolizumab. The majority of Roche sponsored ongoing trials are early phase trials, with 83% in phases I-II. Of the 29 trials Roche is currently sponsoring, 15 target only breast cancer patients.
Immuno-oncology agents are being tested as a primary drug in 30% of the 204 ongoing industry sponsored trials that include TNBC patients. Figure 4 illustrates the top 10 primary drugs utilized in these trials. The most common primary drug being studied in TNBC patients is Merck’s PD-1 antagonist, pembrolizumab. While Roche is the leading sponsor of trials involving TNBC patients, the company is evaluating a larger variety of drugs in their trials, including the already approved bevacizumab.
Although TNBC represents a small population of patients with breast cancer, the commitment is apparent to develop effective treatments. The market is expected to expand in this area and data in late phase trials for targeted agents is expected in the next few years.
 2016 May 23, Datamonitor Healthcare, Breast cancer: triple negative disease coverage