Lengo’s drug targets a mutation in the gene that drives production of a protein called EGFR, which, in turn, can help spur tumor growth. The mutation, found in the exon 20 region of the gene, is present in about 2% of non-small cell lung tumors, a number that equates to about 2,000 to 3,000 cases each year in the U.S.

Several drugs target EGFR broadly, among them AstraZeneca’s Tagrisso and Boehringer Ingelheim’s Gilotrif. But in 2021, significant progress was made towards a more precise approach, as the FDA cleared two drugs aimed at exon 20 mutations: J&J’s Rybrevant and Takeda’s Exkivity.

Those drugs aren’t perfect, however. Rybrevant requires a complicated dosing strategy to prevent injection reactions, while Exkvity is associated with cardiovascular side effects, Stifel analyst Bradley Canino wrote in a Nov. 29 note to clients. Both are modestly effective: Rybrevant shrank or eliminated tumors in 40% of the patients in clinical testing, while Exkivity did the same for 28% of those who were treated in trials, according to Canino.

Blueprint believes LNG-451 could top both of them because it targets the mutated protein more precisely and can penetrate into brain tissue, where lung cancer tumors often spread. But it’s not the only one trying to improve upon J&J and Takeda’s drugs. Cullinan Oncology and Dizal Pharma each have medicines in Phase 2 trials as well, and both have shown competitive response rates and cleaner safety profiles in early testing.

The tough competition and small potential market for exon 20-targeting drugs — estimated to be around $500 million a year — means Blueprint may have overpaid for Lengo, Canino wrote.

Still, with $1.3 billion in cash as of Sept. 30, the company has plenty of money for additional expansion, although it used $325 million through the first nine months of the year.

Blueprint shares fell 4% in Monday morning trading.