The FDA has granted orphan drug designation to seribantumab (MM-121), an investigational treatment for patients with heregulin-positive non–small-cell lung cancer (NSCLC).1 A fully human monoclonal antibody, seribantumab targets the human epidermal growth factor receptor ErbB3 (HER3), and has potential antitumor activity in combination therapies for patients with NSCLC who have high expression of the heregulin biomarker.1
Seribantumab is currently under investigation in the global, open-label, multicenter, randomized phase 2 SHERLOC study, which is evaluating the drug in combination with docetaxel (Taxotere) compared with docetaxel alone in 80 patients with heregulin-positive NSCLC who have experienced disease progression after treatment with a platinum-based regimen. Patients enrolled in the study also may have received anti–PD-1 or anti–PD-L1 therapy, but have received ≤2 previous systemic therapies. SHERLOC’s primary end point is progression-free survival, and secondary end points include overall survival, objective response rate, time to progression, adverse event rate, and pharmacokinetics. Top-line data from SHERLOC are anticipated in the latter half of 2018.1,2
The FDA grants orphan designation to drugs intended as treatments for rare diseases affecting fewer than 200,000 people throughout the United States. With the designation comes eligibility for marketing exclusivity for 7 years from the time of the drug’s approval, along with additional development assistance and financial incentives. Approximately 101,000 patients with NSCLC throughout the United States are estimated to have heregulin-positive tumors, which are distinguished by the ability to evade the effects of targeted, cytotoxic, and antiendocrine treatments, and are often marked by rapid clinical progression.1
Seribantumab received FDA fast track designation in 2016 for development as a treatment for locally advanced or metastatic heregulin-positive NSCLC that has progressed after treatment with immunotherapy.3
In addition, the global, randomized phase 2 SHERBOC trial is investigating seribantumab plus fulvestrant versus fulvestrant alone in patients with heregulin-positive, hormone receptor–positive, HER2-negative metastatic breast cancer.1,4
1. Merrimack receives orphan drug designation for MM-121 for the treatment of heregulin positive non-small cell lung cancer. October 30, 2017. http://investors.merrimack.com/news-releases/news-release-details/merrimack-receives-orphan-drug-designation-mm-121-treatment. Accessed February 23, 2018.
2. ClinicalTrials.gov. A study of MM-121 in combination with chemotherapy versus chemotherapy alone in heregulin positive NSCLC. Updated January 24, 2018. https://clinicaltrials.gov/ct2/show/NCT02387216. Accessed February 23, 2018.
3. FDA grants Merrimack fast track designation for seribantumab (MM-121) in non-small cell lung cancer. July 6, 2016. www.prnewswire.com/news-releases/fda-grants-merrimack-fast-track-designation-for-seribantumab-mm-121-in-non-small-cell-lung-cancer-300294237.html. Accessed February 23, 2018.
4. ClinicalTrials.gov. Phase 2 trial of seribantumab plus fulvestrant in postmenopausal women with metastatic breast cancer (SHERBOC). Updated November 17, 2017. https://clinicaltrials.gov/ct2/show/NCT03241810. Accessed March 16, 2018.