FP14.10 Efficacy and Safety of Selpercatinib (LOXO-292) in East Asian Patients with RET Fusion-Positive NSCLC

Small Molecule Inhibitors as Therapeutic Agents Targeting Oncogenic Fusion Proteins: Current Status and Clinical

Oncogenic fusion proteins, arising from chromosomal rearrangements, have emerged as prominent drivers of tumorigenesis and crucial therapeutic targets in cancer research. In recent years, the potential of small molecular inhibitors in selectively targeting fusion proteins has exhibited significant prospects, offering a novel approach to combat malignancies harboring these aberrant molecular entities. This review provides a comprehensive overview of the current state of small molecular inhibitors as therapeutic agents for oncogenic fusion proteins. We discuss the rationale for targeting fusion proteins, elucidate the mechanism of action of inhibitors, assess the challenges associated with their utilization, and provide a summary of the clinical progress achieved thus far. The objective is to provide the medicinal community with current and pertinent information and to expedite the drug discovery programs in this area.

Selpercatinib: A Review in Advanced RET Fusion-Positive NSCLC

Selpercatinib (Retevmo^®/Retsevmo^®) is an orally-administered, selective inhibitor of rearranged during transfection (RET) kinase approved for the treatment of advanced RET fusion-positive non-small cell lung cancer (NSCLC). In a pivotal phase 1/2 clinical trial in this population, selpercatinib treatment was associated with robust and durable responses, including intracranial responses, in patients previously treated with platinum-based chemotherapy, as well as in treatment-naïve patients. Selpercatinib had a manageable tolerability profile and an acceptable safety profile; adverse events could generally be managed with dose reductions and only a small proportion of patients discontinued selpercatinib due to treatment-related adverse events. The most common treatment-related adverse events that were grade 3-4 in severity were hypertension, elevated alanine aminotransferase and elevated aspartate aminotransferase. Thus, currently available evidence suggests that selpercatinib is a promising new RET-targeted therapy option for patients with advanced RET fusion-positive NSCLC.

Efficacy and safety of selpercatinib in Chinese patients with advanced RET fusion-positive non-small-cell lung cancer: a phase II clinical trial (LIBRETTO-321)

Introduction:

Oncogenic alterations in RET occur in 1–2% of non-small-cell lung cancers (NSCLCs). The efficacy and safety of the first-in-class, highly selective, and potent RET inhibitor selpercatinib in Chinese patients with RET fusion-positive NSCLC remains unknown.

Methods:

In this open-label, multicenter, phase II study (NCT04280081), patients with advanced RET-altered solid tumors received selpercatinib (160 mg orally twice daily) in a 28-day cycle. The primary endpoint was independent review committee (IRC)-assessed objective response rate (ORR; Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints included duration of response, central nervous system (CNS) response, and safety. Efficacy against NSCLC was assessed in the primary analysis set (PAS; centrally confirmed RET status) and in all enrolled patients with NSCLC.

Results:

Of 77 enrolled patients, 47 had RET fusion-positive NSCLC. After 9.7 months of median follow-up, IRC-assessed ORR in the PAS (n = 26) was 69.2% [95% confidence interval (CI), 48.2–85.7] and 94.4% of responses were ongoing; the ORR was 87.5% and 61.1% in treatment-naïve and pre-treated patients, respectively. IRC-assessed ORR in all patients with NSCLC (n = 47) was 66.0% (95% CI, 50.7–79.1). Among five patients with measurable CNS metastases at baseline, four (80%) achieved an IRC-assessed intracranial response. In the safety population (n = 77), most treatment-emergent adverse events (TEAEs) were grade 1 or 2. The most common grade ⩾3 TEAE was hypertension (19.5%). Three (3.9%) patients discontinued therapy due to treatment-related AEs; no deaths occurred due to treatment-related AEs.

Conclusion:

Selpercatinib, with potent and durable antitumor activity including intracranial activity, was well tolerated in Chinese patients with RET fusion-positive NSCLC, consistent with LIBRETTO-001 (ClinicalTrials.gov: NCT04280081).