New Data on Selpercatinib Shows Promise for Certain Gastrointestinal Malignancies and Other Cancers

Selpercatinib (Retevmo; Eli Lilly and Company) demonstrated encouraging antitumor activity and safety across RET fusion-positive advanced solid tumors beyond lung and thyroid cancers, including multiple treatment-refractory gastrointestinal (GI) malignancies, in the Phase 1/2 LIBRETTO-001 trial (NCT03157128). According to Lilly, the data were presented for the first time at the virtual 2021 American Association for Cancer Research Annual Meeting, April 10-15, 2021.

Selpercatinib is a selective RET kinase inhibitor. Lilly’s selpercatinib product received Accelerated Approval from the FDA in May 2020 for the treatment of adult patients with metastatic RET fusion-positive non-small cell lung cancer, in adult and pediatric patients ages 12 years and older with advanced or metastatic RET-mutant medullary thyroid cancer who require systemic therapy, and in adult and pediatric patients aged 12 years and older with advanced or metastatic RET fusion-positive thyroid cancer who require systemic therapy and who are radioactive iodine-refractory (if radioactive iodine is appropriate).

"We are excited to broaden the body of evidence for Retevmo in RET fusion-positive cancers beyond lung and thyroid tumors," said David Hyman, MD, Lilly’s chief medical officer, oncology, in a prepared statement. "These encouraging outcomes, including in difficult-to-treat GI malignancies, support a growing body of evidence that RET fusions are potentially actionable in a wide range of tumor types. These findings further demonstrate the importance of broad tumor profiling in advanced cancers. We look forward to discussing these new data with regulatory authorities this year."

In the LIBRETTO-001 trial, 32 adult patients with 12 unique RET fusion-positive advanced cancer types were enrolled by the efficacy cutoff date of September 19, 2020, with follow-up through March 19, 2021. Cancer types treated included pancreatic, colon, breast, salivary, sarcoma, carcinoid, rectal neuroendocrine, small intestine, xanthogranuloma, ovarian, pulmonary carcinosarcoma, and unknown primary cancers. Among the 32 patients, 62.5% had GI tumors (defined as pancreatic [n=9], colon [n=9], small intestine [n=1], and rectal neuroendocrine [n=1]). Across all 32 patients, the confirmed objective response rate (ORR) was 47% (95% CI: 26-65%). Confirmed responses were observed in nine unique RET fusion-positive advanced cancer types. The median duration of response (DoR) was not reached, with median follow-up of 13 months. Responses were ongoing in 73% (11/15) of responding patients.

Safety among patients in this cohort was consistent with the known selpercatinib safety profile. In this cohort, the most common treatment-emergent adverse events of any grade (≥20%) were increased aspartate aminotransferase /increased alanine aminotransferase, dry mouth, hypertension, diarrhea, fatigue, nausea, and abdominal pain. No patients in this cohort discontinued treatment due to treatment-related adverse events.

"While uncommon, RET fusions occur in a 'long tail' of solid tumors beyond lung and thyroid cancers, and these patients do not yet have an approved targeted therapy option to address the underlying genomic driver of their cancer," said Vivek Subbiah, MD, associate professor in the Investigational Cancer Therapeutics Department and center clinical medical director of the Clinical Center for Targeted Therapy, of the Cancer Medicine Division, at The University of Texas MD Anderson Cancer Center,in a prepared statement. "These results demonstrate selpercatinib's potential for this patient population and reiterate the importance of broad-based genomic profiling to identify actionable oncogenic drivers, including RET fusions."

REFERENCE

Lilly Presents New Data on Retevmo® (selpercatinib) in Advanced RET Fusion-Positive Gastrointestinal and Other Cancers at 2021 American Association for Cancer Research (AACR) Annual Meeting [news release]. April 11, 2021; Eli Lilly and Company. Accessed April 12, 2021. https://prnmedia.prnewswire.com/news-releases/lilly-presents-new-data-on-retevmo-selpercatinib-in-advanced-ret-fusion-positive-gastrointestinal-and-other-cancers-at-2021-american-association-for-cancer-research-aacr-annual-meeting-301266274.html