There's good news for patients with a specific type of lung cancer, and for the companies developing a treatment for it. Taiho Oncology, Taiho Pharmaceutical, and Cullinan Therapeutics (CGEM) announced Thursday that their drug zipalertinib, when combined with chemotherapy, hit its primary goal in a global Phase 3 trial.

The REZILIENT3 study, which tested the combo in patients with previously untreated, locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) with EGFR exon 20 insertion mutations, met its primary endpoint of progression-free survival (PFS) at a planned interim analysis. The improvement was both statistically significant and clinically meaningful compared to chemotherapy alone.

“These topline results give us confidence in the potential for zipalertinib to offer a first-line treatment option for patients with NSCLC with EGFR exon 20 insertion mutations,” said Jeffrey Jones, Chief Medical Officer of Cullinan Therapeutics.

The trial enrolled 285 adults. The Independent Data Monitoring Committee, after seeing the data, recommended unblinding the study so patients and investigators know who got what. The trial will continue to track efficacy and safety.

This is a big deal for Cullinan, which is also awaiting an FDA decision on zipalertinib for a different, earlier-stage use. In April, the FDA accepted a New Drug Application for zipalertinib as a treatment for patients with locally advanced or metastatic NSCLC with EGFR exon 20 insertion mutations whose disease has progressed on or after platinum-based chemotherapy, with or without amivantamab. The Prescription Drug User Fee Act target action date is February 27, 2027.

That application was supported by data from the Phase 2b part of the REZILIENT1 trial, which tested zipalertinib as a monotherapy. In that study, the confirmed objective response rate (ORR) was 35%, with a median duration of response of 8.8 months. Among patients who had only received prior platinum-based chemotherapy (n=125), the ORR was 40%, with the same median duration of response.

On the financial side, Cullinan reported cash, cash equivalents, short- and long-term investments, and interest receivable of $356 million as of June 30. The company expects that cash runway to last into 2029.

Analysts are already sizing up how zipalertinib might fit into the treatment landscape. William Blair's Matt Phipps noted that zipalertinib's “strong efficacy and tolerability could prove beneficial in the first-line setting, where Johnson & Johnson's (JNJ) Rybrevant (amivantamab) plus chemotherapy is approved but has tolerability issues.”

Phipps also pointed to AstraZeneca (AZN), which recently acquired the commercialization rights to Zegfrovy from Dizal Pharmaceutical. He expects Zegfrovy to be commercialized in the U.S. soon, adding another competitor to the mix.

Investors seemed pleased with Thursday's news. Cullinan Therapeutics shares were up 1.79% at $19.95 at the time of publication, trading at a new 52-week high.

For patients, the potential of a first-line option that's both effective and tolerable is a meaningful step forward. For Cullinan, it's a validation of its science and a potential path to a broader market. The next big milestone is the FDA's decision on the second-line indication, which will come early next year.