Research progress on the impact of radiation on TKI resistance mechanisms in NSCLC

Drug conjugates for the treatment of lung cancer: from drug discovery to clinical practice

A drug conjugate consists of a cytotoxic drug bound via a linker to a targeted ligand, allowing the targeted delivery of the drug to one or more tumor sites. This approach simultaneously reduces drug toxicity and increases efficacy, with a powerful combination of efficient killing and precise targeting. Antibody‒drug conjugates (ADCs) are the best-known type of drug conjugate, combining the specificity of antibodies with the cytotoxicity of chemotherapeutic drugs to reduce adverse reactions by preferentially targeting the payload to the tumor. The structure of ADCs has also provided inspiration for the development of additional drug conjugates. In recent years, drug conjugates such as ADCs, peptide‒drug conjugates (PDCs) and radionuclide drug conjugates (RDCs) have been approved by the Food and Drug Administration (FDA). The scope and application of drug conjugates have been expanding, including combination therapy and precise drug delivery, and a variety of new conjugation technology concepts have emerged. Additionally, new conjugation technology-based drugs have been developed in industry. In addition to chemotherapy, targeted therapy and immunotherapy, drug conjugate therapy has undergone continuous development and made significant progress in treating lung cancer in recent years, offering a promising strategy for the treatment of this disease. In this review, we discuss recent advances in the use of drug conjugates for lung cancer treatment, including structure-based drug design, mechanisms of action, clinical trials, and side effects. Furthermore, challenges, potential approaches and future prospects are presented.

Efficacy of epidermal growth factor receptor tyrosine kinase inhibitors in patients with recurrent non-small cell lung cancer after definitive concurrent chemoradiation or radiotherapy

PURPOSE

Whether prior radiotherapy (RT) affects the response of EGFR-mutated non-small cell lung cancer (NSCLC) to EGFR tyrosine kinase inhibitor (TKI) remains elusive.

METHODS

Patients with EGFR-mutated NSCLC treated with EGFR TKIs who recurred after curative treatment at Asan Medical Center, Seoul, Korea were included. The progression-free survival (PFS) and overall survival (OS) from the initiation of EGFR TKI in patients who recurred after definitive RT were analyzed and compared to the outcomes of RT-naïve patients with advanced NSCLC treated with EGFR TKIs from previously reported prospective clinical trial results.

RESULTS

A total of 60 patients who recurred after definitive RT were included. The median age was 70 years (range, 38-88), with 24 patients (40.0%) being males. Among the 60 patients, 52 patients (86.7%) had exon 19 deletion or L858R mutation, with 49 patients (81.7%) receiving gefitinib as the first-line EGFR TKI. The median PFS and OS from the initiation of EGFR TKI were 10.4 months (95% confidence interval [CI], 7.4-13.2) and 21.3 months (95% CI, 13.4-28.8), respectively.

CONCLUSION

The EGFR TKI efficacy in EGFR-mutated patients with NSCLC who recurred after RT was comparable with that in historic controls of RT-naïve patients with advanced NSCLC treated with EGFR TKIs, indicating that RT may not affect EGFR TKI efficacy.

Primary lesion radiotherapy during first-line icotinib treatment in EGFR-mutated NSCLC patients with multiple metastases and no brain metastases: a single-center retrospective study

BACKGROUND

The most frequent mode of progression in the majority of non-small cell lung cancer (NSCLC) patients treated with  Epidermal growth factor - receptor tyrosine kinase inhibitors (EGFR-TKIs) is failure to respond to treatment at the primary lesion, suggesting that concurrent radiotherapy (CRT) to the primary lesion (CPRT) during first-line treatment with EGFR-TKI may be a novel therapeutic approach with a potential of additional benefit for metastatic NSCLC. Therefore, this study investigated the progression-free survival (PFS) and safety of CPRT during first-line icotinib treatment in NSCLC patients with EGFR mutations.

METHODS

EGFR-mutant NSCLC patients diagnosed with limited multiple metastases were treated with first-line icotinib. The decision to treat the primary lesions with radiation largely depended on the patient's preference. The study endpoints included PFS, toxicity, progression pattern, and acquisition of the T790M mutation.

RESULTS

The median PFS in the CPRT and Non-CPRT groups was 13.6 and 10.6 months (hazard ratio [HR] 0.23, 95% confidence interval [CI] 0.15-0.37, P < 0.001). Subgroup analysis showed that the results were statistically significant with 14.7 and 11.5 months for the 19del mutation (HR 0.20, 95% CI 0.10-0.40, P < 0.001) and 12.9 and 9.9 months for the L858R mutation (HR 0.25, 95% CI 0.13-0.48, P < 0.001). There were no reports of interstitial pneumonia associated with treatment at grade 4 or above. Patients who received CPRT during first-line icotinib treatment had the potential to decrease the primary lesion progression (P < 0.05) without increasing newly metastatic lesions (P > 0.05). The proportion of acquired T790M mutations was 26.7% and 45.7% in both groups (P > 0.05).

CONCLUSION

This study suggests that CPRT is a viable option for patients with EGFR-sensitive mutations in NSCLC with limited multiple metastases during first-line icotinib treatment, which can significantly improve PFS with acceptable toxicities. Data on progression patterns and T790M mutations suggest the need to further investigate the benefits of radiation treatment from a molecular perspective.