Eli Lilly's Retevmo wins FDA nod to treat all cancer types with rare RET biomarker

How about this for a label expansion?

Two years after blessing Eli Lilly’s Retevmo to treat lung and thyroid cancers caused by a specific biomarker, the FDA has authorized the drug to be used across all tumor types that bear the biomarker.

Wednesday’s action by the United States regulator covers all cancers driven by alterations in the rearranged during transfection (RET) gene. Retevmo is available for all locally advanced or metastatic solid tumors, following prior systemic treatment or with no other treatment alternatives.

With the endorsement coming under the accelerated pathway, it will be subject to review in confirmatory studies. RET cancers are rare, though occurring predominantly in non-small cell lung cancer (NSCLC) and thyroid cancers.

The rapid tumor-agnostic approval was based on Retevmo showing that it shrunk various tumor types by 44% among those with the biomarker and provided benefits for a median of 24.5 months.

Expanding Retevmo’s use will be particularly key in treating pancreatic and colon cancers, Vivek Subbiah, M.D., of the University of Texas and co-investigator of the Libretto-001 trial, said in a statement.

In the study, of 11 patients with pancreatic cancer, Retevmo shrunk tumors in 55%. In 10 patients with colorectal cancer, it produced an overall response rate of 20%.

The data and approval show the "importance of routine, comprehensive genomic testing for patients across a wide variety of tumor types," Subbiah added. The genomic test used to determine if a patient has the RET biomarker is FDA approved.  

In addition to the tumor-agnostic green light, the FDA also signed off on Retevmo to treat adults for locally advanced NSCLC. The previous approval in the indication covered just metastatic solid tumors. The new move converted the May 2020 FDA action from an accelerated to a full endorsement. 

The full approval in NSCLC was based on Retevmo showing tumor shrinkage in 84% of patients compared to 61% on platinum-based chemotherapy. While Retevmo patients had a median duration of response of 20.2 months, chemotherapy sustained for a median of 28.6 months.

Retevmo becomes the first and only RET inhibitor to receive a tumor-agnostic accelerated approval and a traditional approval in NSCLC.

Lilly acquired Retevmo in its $8 billion buyout of Loxo Oncology in 2019. The drug generated sales of $87 million in the first half of this year, up from $42 million in the first half of 2021.