Expanded Access Program Pralsetinib in Advanced Non-Small Cell Lung Cancer with Rearranged during Transfection (RET) Gene Rearrangement

RET Fusion Testing in Patients With NSCLC: The RETING Study

Introduction

RET inhibitors with impressive overall response rates are now available for patients with NSCLC, yet the identification of RET fusions remains a difficult challenge. Most guidelines encourage the upfront use of next-generation sequencing (NGS), or alternatively, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) when NGS is not possible or available. Taken together, the suboptimal performance of single-analyte assays to detect RET fusions, although consistent with the notion of encouraging universal NGS, is currently widening some of the clinical practice gaps in the implementation of predictive biomarkers in patients with advanced NSCLC.

Methods

This situation prompted us to evaluate several RET assays in a large multicenter cohort of RET fusion-positive NSCLC (n = 38) to obtain real-world data. In addition to RNA-based NGS (the criterion standard method), all positive specimens underwent break-apart RET FISH with two different assays and were also tested by an RT-PCR assay.

Results

The most common RET partners were KIF5B (78.9%), followed by CCDC6 (15.8%). The two RET NGS-positive but FISH-negative samples contained a KIF5B(15)-RET(12) fusion. The three RET fusions not identified with RT-PCR were AKAP13(35)-RET(12), KIF5B(24)-RET(9) and KIF5B(24)-RET(11). All three false-negative RT-PCR cases were FISH-positive, exhibited a typical break-apart pattern, and contained a very high number of positive tumor cells with both FISH assays. Signet ring cells, psammoma bodies, and pleomorphic features were frequently observed (in 34.2%, 39.5%, and 39.5% of tumors, respectively).

Conclusions

In-depth knowledge of the advantages and disadvantages of the different RET testing methodologies could help clinical and molecular tumor boards implement and maintain sensible algorithms for the rapid and effective detection of RET fusions in patients with NSCLC. The likelihood of RET false-negative results with both FISH and RT-PCR reinforces the need for upfront NGS in patients with NSCLC.

Clinical evidence and adverse event management update of patients with RET- rearranged advanced non-small-cell lung cancer (NSCLC) treated with pralsetinib

Current non-small cell lung cancer (NSCLC) management relies on genome-driven precision oncology thus shifting treatment paradigm towards biomarker-guided tumor-agnostic approaches. Recently, rearranged during transfection (RET) has been endorsed as tissue-agnostic target with sensitivity to RET inhibition. There are currently two selective RET tyrosine kinase inhibitors, pralsetinib and selpercatinib. The recent introduction of pralsetinib in the treatment algorithm of RET-rearranged tumor along with the mounting clinical evidence of pralsetinib durable activity from both randomized and observational studies holds the potential to disclose new avenues in the management of RET fusion positive NSCLC patients. Our narrative review aims to discuss the available clinical evidence on pralsetinib efficacy, particularly on brain metastases, and tolerability profile. In addition, our work explores the relevance of detecting RET fusions upfront in the disease history of patients with NSCLC.

First-line versus second-line use of pralsetinib in treatment of rearranged during transfection (RET) fusion-positive advanced non-small cell lung cancer: a cost-effectiveness analysis

Background

The ARROW study demonstrated favorable clinical efficacy and safety of pralsetinib (PRL) in treating rearranged during transfection (RET) fusion positive non-small cell lung cancer (NSCLC) in clinical trials. However, due to the high cost of PRL, evaluating its cost-effective characteristics is crucial. Currently, there has been no cost-effectiveness analysis specifically for PRL. Therefore, the aim of this study was to assess the cost-effectiveness characteristics of using PRL as a first-line therapy versus reserving it until the second-line versus solely relying on chemotherapy from the perspective of payers in the United States.

Methods

A Markov model was developed to evaluate the 3 above mentioned PRL-based treatment strategies. Clinical data from the ARROW trial were incorporated into the model, and costs and utilities values were obtained through previously published literature and public databases, with both being discounted at 3% per year. To ensure the robustness of the model, both probabilistic and univariate sensitivity analyses were performed. The primary endpoints included quality-adjusted life years (QALYs), lifetime costs, and incremental cost-effectiveness ratio (ICER).

Results

Compared to chemotherapy, the use of PRL in the first-line therapy resulted in an additional 0.07 QALYs at a cost of $133,561, with an ICER of $1,353,849.65 per QALY. Similarly, when used in the second-line setting, PRL led to an additional 0.09 QALYs at a cost of $92,797, with an ICER of $559,232.70 per QALY. The ICER value in the first-line or in the second-line therapy strategy was higher than the US willingness-to-pay (WTP) threshold of $150,000 per QALY. Univariable sensitivity analyses revealed that the cost of PRL and the utility of progressed disease had the most significant impact on the ICER. To be considered cost-effective at a WTP threshold of $150,000 per QALY, the cost of PRL would need to be reduced by 71.34% in first-line treatment or 84.49% in second-line treatment.

Conclusions

Based on current pricing, neither PRL as first-line nor second-line therapy was found to be cost-effective for patients with RET fusion-positive advanced NSCLC compared to chemotherapy. Reserving PRL until second-line therapy may be a compromise approach to maintaining control over healthcare expenses yet still achieving favorable clinical outcomes.