Savolitinib, a selective oral tyrosine kinase inhibitor, showed good activity against locally advanced or metastatic non–small cell lung cancer (NSCLC) bearing MET exon 14 mutations as both first-line therapy for treatment-naive patients and in second-line of therapy for previously treated patients
“The phase 3b study results further confirm savolitinib as a valuable targeted therapy option for naive and previously-treated non–small cell lung cancer with MET 14 exon mutations,” Yongchang Zhang, MD, said while presenting the final results of the trial at the European Lung Cancer Congress 2024.
For 87 previously untreated patients the objective response rate (ORR) as assessed by independent review, the primary endpoint, was 62.1%. For 79 patients receiving savolitinib in the second line, the ORR was 39.2%, reported Dr. Zhang, MD, of the Hunan Cancer Hospital in Changsha, China.
Preliminary results of this trial were reported at the World Conference on Lung Cancer in 2023.
Selective Inhibitor
Savolitinib (AZD6094, also called volitinib) is reported to be a highly selective oral inhibitor of the MET receptor tyrosine kinase (TKI). It is approved in China for the treatment of patients with NSCLC harboring MET exon 14 mutations that has progressed on prior systemic therapy, or patients who are unable to tolerate platinum-based chemotherapy.
In the phase 3b study, patients with MET ex14-positive tumors who were negative for EGFR, ALK or ROS1 alterations and were naive to a MET inhibitor were enrolled. Those who weighed 50 kg or greater received 600 mg savolitinib orally once daily for each 21-day cycle, while patients who weighed less than 50 kg received a 400-mg daily dose. Therapy continued until disease progression, death, or unacceptable toxicity.
Tumors were evaluated by investigators every 6 weeks for the first year, than every 12 weeks thereafter.
As noted before, ORR by independent review was 62.1% for treatment-naive patients and 39.2% for previously treated patients. The respective ORRs by investigator assessment were 59.8% and 43%. All responses in each arm were partial responses.
Median progression-free survival (PFS) after a median follow-up of 18 months for treatment-naive patients and 11 months for treatment-experienced patients was 13.7 months and 11 months, respectively.
Overall survival after a median follow-up of 20.8 months for treatment-naive patients and 12.5 months for previously treated patients was not reached in treatment-naive patients and not mature in treatment-experienced patients.
Grade 3 or greater treatment-emergent adverse events occurred in 74.1% of patients, including 3 events (1.8%) leading to death. Dose modifications were required for 74.7% of patients.
Grade 3 or greater adverse events included peripheral edema, liver enzyme elevations, abnormal liver function, decreased platelet and white blood cell counts, and vomiting.
Which TKI is Best?
Invited discussant Antonio Passaro, MD, PhD, from the European Institute of Oncology in Milan, noted that eligibility for treatment with savolitinib or other MET exon 14-targeting TKIs is limited to about 3% of patients with NSCLC of adenocarcinoma histology.
He said that savolitinib appears to be similar in performance to two other TKIs for NSCLC with MET exon-14 skipping mutations that are currently on the market in the United States, Europe, and Japan: capmatinib (Tabrecta) and tepotinib (Tepmetko).
“Globally, all the results show a numerically better performance when we use a selective TKI in first-line treatment over the second-line treatment, in particular for overall response rate,” he said.
Dr. Passaro noted that savolitinib differs from the other two MET TKIs in that PFS with savolitinib is similar for treatment-naive and previously treated patients.
He added, however, that “today it’s very difficult” to determine which is the “perfect” agent for a specific disease presentation, particularly since MET exon 14 skipping mutations can also be found in patients with squamous cell carcinomas and those with a history of smoking.
To get a better sense of which drug to use in a specific situation, it would be helpful to analyze trial results in the context of tumor histology, smoking history, programmed death protein 1-ligand 1 status, and co-mutations, he said.
The study was sponsored by Hutchmed. Dr. Zhang reported having no conflicts of interest. Dr. Passaro reported a consulting, advisory, or speakers bureau role for multiple companies, not including Hutchmed.