Lilly keeps ahead of Blueprint with swift FDA review for selpercatinib

Eli Lilly says it is eyeing an FDA verdict for RET-positive tumour treatment selpercatinib in the third quarter of this year, which would extend its lead over a rival drug from Blueprint Medicine.

The US regulator has started a priority review for selpercatinib (LOXO-292) in RET fusion-positive non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC) and thyroid cancer based on the results of the phase 1/2 LIBRETTO-001 trial reported last September.

That study revealed a 68% response rate in NSCLC, as well as a 62% rate in thyroid cancers.

The priority review sets up a verdict for the marketing application in six months rather than the usual 10, and keeps selpercatinib ahead of Blueprint’s pralsetinib (BLU-667), which hasn’t yet been submitted for approval but is due for filing in NSCLC this quarter, with a thyroid cancer application due shortly after.

Lilly is now in pole position to bring a RET inhibitor to market, providing a new option for the roughly 2% of NSCLC patients who carry this particular mutation, which is also seen in 20% to 40% of thyroid cancer cases, and up to 70% of MTC patients.

If approved, it will be used in later-line treatment, for example after platinum-based chemotherapy and PD-1/PD-L1 checkpoint inhibitor has failed in NSCLC, and as a last-line treatment for thyroid cancer after other drugs like Exelixis’s Cabometyx (cabozantinib) or Sanofi’s Caprelsa (vandetinib).

Lilly is also running two 400-patient phase 3 trials that it will allow selpercatinib to move further up the treatment pathway.

LIBRETTO-431 will test the drug in patients with previously-untreated patients with RET-positive NSCLC, while LIBRETTO-531 involves patients with treatment-naïve RET-positive MTC. Extension of the drug into those first-line setting will of course require screening for these mutations.

Lilly acquired selpercatinib as part of its $8 billion takeover of Loxo Oncology last year, and the drug was billed as the most promising asset in that deal, alongside oral BTK inhibitor LOXO-305.

Loxo was also behind development of Vitrakvi (larotrectinib) – the first TRK inhibitor to reach the market – as well as follow-up LOXO-195, which were both acquired by Bayer ahead of the Lilly takeover.

The deal is viewed as an attempt by Lilly to rejuvenate its oncology division after falling behind rivals in the category, and it retained Loxo’s chief executive Josh Bilenker as its head of cancer R&D to help spearhead that effort. EvaluatePharma has said selpercatinib could become a $500 million-plus product by 2024.

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