Racing Blueprint, Lilly drug gets priority review for RET hopeful

TFT-admin | January 29, 2020

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by Nick Paul Taylor

Eli Lilly is racing to FDA while working to put selpercatinib through phase 3. (Eli Lilly)

The FDA has granted a priority review to Eli Lilly’s selpercatinib, setting the stage for a third-quarter decision on whether to approve the RET inhibitor. Lilly based its filing on a phase 1/2 trial that linked selpercatinib to objective response rates (ORRs) of over 50% in heavily pretreated cancer patients.

Selpercatinib, also known as LOXO-292, landed in Lilly’s pipeline via the $8 billion acquisition of Loxo Oncology. The drug topped the list of Loxo assets Lilly highlighted at the time of the takeover. Months later, Lilly backed up its belief in the asset with clinical data suggesting the drug improves outcomes in subpopulations of thyroid and non-small cell lung cancer (NSCLC) patients with limited treatment options.

Now, Lilly has taken another step toward bringing selpercatinib to market. The FDA’s decision to put selpercatinib through its priority review pathway stands to shave months off the regulatory process, resulting in a third-quarter PDUFA date. The priority review applies to advanced RET fusion-positive NSCLC and two types of thyroid cancer. 

The timeline puts Lilly on track to be the first company to bring a RET inhibitor to the U.S. market. Lilly’s closest rival is Blueprint Medicines’ pralsetinib, also known as BLU-667. Pralsetinib achieved a 61% ORR in RET fusion-positive NSCLC patients earlier this month, giving Blueprint the data it needs to aim to complete a filing in the indication this quarter.

Blueprint plans to follow up the completion of the NSCLC submission by filing for approval in thyroid cancer the following quarter. If pralsetinib and selpercatinib win FDA approval, Blueprint and Lilly will enter into a scrap for market share while working to generate additional data on their assets. 

Lilly unveiled the next step in its clinical development strategy late last year when it began a phase 3 trial in treatment-naïve RET-mutant medullary thyroid cancer. The initiation of the trial came shortly after Lilly began enrolling patients with treatment-naive RET fusion-positive NSCLC in another phase 3.

The studies stand to catapult selpercatinib up the care pathway. Selpercatinib has mainly been tested to date in patients who have previously been treated with more than one multikinase inhibitor, such as Exelixis’ Cabometyx or Sanofi’s Caprelsa. The next stage of selpercatinib development will move the drug into first-line settings, positioning Lilly to learn whether the molecule can become the go-to option for newly diagnosed patients with certain RET-mutant and RET fusion-positive cancers.