A phase II trial of erlotinib as maintenance treatment after concurrent chemoradiotherapy in stage III non-small-cell lung cancer (NSCLC): a Galician Lung Cancer Group (GGCP) study

Treatment-Related Pneumonitis of EGFR Tyrosine Kinase Inhibitors Plus Thoracic Radiation Therapy in Patients With Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

Thoracic radiation therapy (RT) for non-small cell lung cancers may overcome resistance to tyrosine kinase inhibitors (TKIs). However, the risk of severe treatment-related pneumonitis (TRP) is a major concern, and the results of the combined treatment remain controversial. Therefore, we aimed to systematically review existing publications and provide a meta-analysis of TRP from a combined therapy of thoracic RT and TKIs. A systematic literature review was performed using the PubMed-MEDLINE and Embase databases to identify eligible publications. The number of severe TRP cases of grade 3 or higher was extracted and then analyzed by fixed or randomized model meta-analysis. Heterogeneity tests were performed using the I² and τ² statistics. Subgroup analyses were conducted on the types of RT and the sequence of the combined treatment. Our literature search identified 37 eligible studies with 1143 patients. Severe TRP occurred in 3.8% (95% CI, 1.8%-6.5%) of patients overall, and fatal pneumonitis occurred rarely in 0.1% (95% CI, 0.0%-0.3%). In the subgroup analysis, the severe TRP proportion was 2.3% (95% CI, 1.0%-4.1%) for patients under definitive (chemo)RT (19 studies, n = 702) versus 2.9% (95% CI, 1.3%-5.1%) for patients who received local stereotactic body RT or palliative RT (15 studies, n = 361). The severe TRP rate was 4.9% (95% CI, 2.4%-8.1%) for concurrent TKI and RT (26 studies, n = 765), which was significantly higher than TRP of 0.4% (95% CI, 0.0%-3.1%) for sequential therapy (6 studies, n = 200). Our meta-analysis showed that combined thoracic RT and epidermal growth factor receptor-TKI therapy has an acceptable risk of severe TRP and rare mortality in patients with non-small cell lung cancers. Concurrent treatment is less tolerable and should be administered with caution. Further investigations using osimertinib are required as the data on its effects are limited.

Consolidation Systemic Therapy in Locally Advanced, Inoperable Nonsmall Cell Lung Cancer-How to Identify Patients Which Can Benefit from It?

BACKGROUND

Consolidation systemic therapy (ST) given after concurrent radiotherapy (RT) and ST (RT-ST) is frequently practiced in locally advanced inoperable nonsmall cell lung cancer (NSCLC). Little is known, however, about the fate of patients achieving different responses after concurrent phases of the treatment.

METHODS

we searched the English-language literature to identify full-length articles on phase II and Phase III clinical studies employing consolidation ST after initial concurrent RT-ST. We sought information about response evaluation after the concurrent phase and the outcome of these patient subgroups, the patterns of failure per response achieved after the concurrent phase as well as the outcome of these subgroups after the consolidation phase.

RESULTS

Eighty-seven articles have been initially identified, of which 20 studies were excluded for various reasons, leaving, therefore, a total of 67 studies for our analysis. Response evaluation after the concurrent phase was performed in 36 (54%) studies but in only 14 (21%) response data were provided, while in 34 (51%) studies patients underwent a consolidation phase regardless of the response. No study provided any outcome (survivals, patterns of failure) as per response achieved after the concurrent phase.

CONCLUSIONS

Information regarding the outcome of subgroups of patients achieving different responses after the concurrent phase and before the administration of the consolidation phase is still lacking. This may negatively affect the decision-making process as it remains unknown which patients may preferentially benefit from the consolidation of ST.

Locally Advanced, Unresectable Non-Small Cell Lung Cancer

PURPOSE OF REVIEW

Treatment of locally advanced, unresectable non-small cell lung cancer (NSCLC) has recently been revolutionized by the incorporation of immunotherapy to standard platinum-based concurrent chemoradiation. This review examines the current standard practices and ongoing studies on the management of locally advanced, unresectable NSCLC.

RECENT FINDINGS

Concurrent chemoradiation is the cornerstone of treatment of unresectable, locally advanced NSCLC. However, chemoradiation can be associated with high therapy-related toxicities, and risk of disease relapse remains significantly elevated despite treatment with curative intent. Durvalumab, a PD-L1 inhibitor, was recently approved as consolidation therapy following concurrent chemoradiation; this agent represents a major advancement in treatment of unresectable stage III NSCLC. Several clinical trials are currently underway to evaluate the benefit of different immunotherapy sequencing and other biomarker-driven strategies in this disease setting. Multiple trials are presently ongoing to assess novel immunotherapy and targeted therapy strategies to improve outcomes and decrease treatment-associated toxicities in patients with locally advanced NSCLC.

Targeting DNA Double-Strand Break Repair Pathways to Improve Radiotherapy Response

More than half of cancer patients receive radiotherapy as a part of their cancer treatment. DNA double-strand breaks (DSBs) are considered as the most lethal form of DNA damage and a primary cause of cell death and are induced by ionizing radiation (IR) during radiotherapy. Many malignant cells carry multiple genetic and epigenetic aberrations that may interfere with essential DSB repair pathways. Additionally, exposure to IR induces the activation of a multicomponent signal transduction network known as DNA damage response (DDR). DDR initiates cell cycle checkpoints and induces DSB repair in the nucleus by non-homologous end joining (NHEJ) or homologous recombination (HR). The canonical DSB repair pathways function in both normal and tumor cells. Thus, normal-tissue toxicity may limit the targeting of the components of these two pathways as a therapeutic approach in combination with radiotherapy. The DSB repair pathways are also stimulated through cytoplasmic signaling pathways. These signaling cascades are often upregulated in tumor cells harboring mutations or the overexpression of certain cellular oncogenes, e.g., receptor tyrosine kinases, PIK3CA and RAS. Targeting such cytoplasmic signaling pathways seems to be a more specific approach to blocking DSB repair in tumor cells. In this review, a brief overview of cytoplasmic signaling pathways that have been reported to stimulate DSB repair is provided. The state of the art of targeting these pathways will be discussed. A greater understanding of the underlying signaling pathways involved in DSB repair may provide valuable insights that will help to design new strategies to improve treatment outcomes in combination with radiotherapy.

Osimertinib (AZD9291) increases radio‑sensitivity in EGFR T790M non‑small cell lung cancer

Osimertinib (AZD9291) is a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated significant clinical benefits in patients with EGFR‑sensitizing mutations or the T790M mutation. However, the potential therapeutic effect of osimertinib combined with ionizing irradiation (IR) is not well understood. The present study investigated treatment with osimertinib combined with IR in EGFR T790M non‑small cell lung cancer (NCI‑H1975) in vitro and in vivo. The results revealed that osimertinib inhibited proliferation and clonogenic survival following irradiation, decreased G2/M phase arrest in irradiated cells, and delayed DNA damage repair in a concentration‑ and time‑dependent manner. Furthermore, osimertinib alone or in combination with IR, blocked the phosphorylation of EGFR (Tyr1068/Tyr1173), protein kinase B and extracellular signal‑regulated kinase. Osimertinib also enhanced the antitumor activity of IR in tumor‑bearing nude mice. The results of the present study indicated that osimertinib has therapeutic potential as a radiation‑sensitizer in lung cancer cells harboring the EGFR T790M mutation, providing a rationale for clinically combining osimertinib with irradiation in EGFR T790M non‑small cell lung cancer.

Eventual role of EGFR-tyrosine kinase inhibitors in early-stage non-small-cell lung cancer

Nonadvanced non-small-cell lung cancer (NSCLC) has a poor long-term survival from surgery or definitive radiation that is minimally improved with induction/adjuvant conventional chemotherapy. EGFR-tyrosine kinase inhibitors (TKIs), which provide a significant benefit for molecularly selected EGFR-mutant patients with advanced NSCLC, have been infrequently explored in nonadvanced NSCLC to date. Current published studies reported no significant benefit from adding EGFR-TKI to the induction/adjuvant setting. However, many of them present eventual biases such as unpowered statistics, lack of molecular selection, recruitment of low-risk NSCLC, low sample size or unsuitable control arms. Results, strengths and deficiencies of completed and ongoing trials were fully discussed. Similarly, the selection of patients and control arms, the duration and risks of EGFR-TKI therapies in early-stage NSCLC, the evaluation of response and the diagnosis of EGFR status were considered and analyzed.

Adding Erlotinib to Chemoradiation Improves Overall Survival but Not Progression-Free Survival in Stage III Non-Small Cell Lung Cancer

Background

Concurrent chemoradiotherapy is the standard of care for inoperable stage III non-small cell lung cancer (NSCLC) for patients who can tolerate it. We explored if adding erlotinib would increase the effectiveness of chemoradiotherapy without increasing toxicity in a single-arm prospective phase II trial.

Methods

Forty-eight patients with previously untreated NSCLC received intensity-modulated radiation therapy (63 Gy/35 fractions) on Monday–Friday, with chemotherapy (paclitaxel 45 mg/m², carboplatin AUC=2) on Mondays, for 7 weeks. All patients also received the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib (150 mg orally 1/day) on Tuesday–Sunday for 7 weeks followed by consolidation paclitaxel–carboplatin. The primary endpoint was time to progression; secondary endpoints were overall survival (OS), toxicity, response, and disease control and whether any endpoint differed by EGFR mutation status.

Results

Of 46 patients evaluable for response, 40 were former or never-smokers and 41 were evaluable for EGFR mutations (37 wild-type [wt] and 4 [mutated; all adenocarcinoma]). Median time to progression was 14.0 months and did not differ by EGFR status. Toxicity was acceptable (no grade 5, one grade 4, eleven grade 3). Twelve patients (26%) had complete responses (10 wt, 2 mutated), 27 (59%) partial (21 wt, 2 mutated, 4 unknown), and 7 (15%) none (6 wt, 2 mutated, 1 unknown) (P=0.610). At 37.0 months’ follow-up (range 3.6–76.5 months) for all patients, median OS time was 36.5 months and 1-, 2-, and 5-year OS rates were 82.6%, 67.4%, and 35.9%; none differed by mutation status. Twelve patients had no progression and 34 had local and/or distant failure. Eleven of 27 distant failures were in the brain (7 wt, 3 mutated, 1 unknown).

Conclusions

Toxicity and OS were promising, but time to progression did not meet expectations. The prevalence of distant failures underscores the need for effective systemic therapy.