Cancer immunology. Mutational landscape determines sensitivity to PD-1 blockade in non-small cell lung cancer

Immune checkpoint inhibitors, which unleash a patient's own T cells to kill tumors, are revolutionizing cancer treatment. To unravel the genomic determinants of response to this therapy, we used whole-exome sequencing of non-small cell lung cancers treated with pembrolizumab, an antibody targeting programmed cell death-1 (PD-1). In two independent cohorts, higher nonsynonymous mutation burden in tumors was associated with improved objective response, durable clinical benefit, and progression-free survival. Efficacy also correlated with the molecular smoking signature, higher neoantigen burden, and DNA repair pathway mutations; each factor was also associated with mutation burden. In one responder, neoantigen-specific CD8+ T cell responses paralleled tumor regression, suggesting that anti-PD-1 therapy enhances neoantigen-specific T cell reactivity. Our results suggest that the genomic landscape of lung cancers shapes response to anti-PD-1 therapy.

Cancer immunology. Mutational landscape determines sensitivity to PD-1 blockade in non-small cell lung cancer

Immune checkpoint inhibitors, which unleash a patient's own T cells to kill tumors, are revolutionizing cancer treatment. To unravel the genomic determinants of response to this therapy, we used whole-exome sequencing of non-small cell lung cancers treated with pembrolizumab, an antibody targeting programmed cell death-1 (PD-1). In two independent cohorts, higher nonsynonymous mutation burden in tumors was associated with improved objective response, durable clinical benefit, and progression-free survival. Efficacy also correlated with the molecular smoking signature, higher neoantigen burden, and DNA repair pathway mutations; each factor was also associated with mutation burden. In one responder, neoantigen-specific CD8+ T cell responses paralleled tumor regression, suggesting that anti-PD-1 therapy enhances neoantigen-specific T cell reactivity. Our results suggest that the genomic landscape of lung cancers shapes response to anti-PD-1 therapy.

Poor response to erlotinib in patients with tumors containing baseline EGFR T790M mutations found by routine clinical molecular testing

BACKGROUND

EGFR T790M is the most common mutation associated with acquired resistance to EGFR tyrosine kinase inhibitors (TKIs). Baseline EGFR T790M mutations in EGFR TKI-naïve patients have been reported, but the frequency and their association with response to EGFR TKIs remain unclear.

PATIENTS AND METHODS

The frequency of baseline EGFR T790M as detected by routine molecular genotyping was determined by reviewing clinical results obtained at our institution from 2009 to 2013. We also collected outcome data for treatment with EGFR TKIs.

RESULTS

To define the incidence of EGFR T790M, we reviewed 2774 sequentially tested patients with lung cancer who underwent molecular testing using a mass spectrometry-based assay, and 11 (0.5%) had baseline EGFR T790M. Compiling results from several molecular techniques, we observed EGFR T790M in tumors from 20 patients who had not previously been treated with an EGFR TKI. In all cases, EGFR T790M occurred concurrently with another EGFR mutation, L858R (80%, 16/20), or exon 19 deletion (20%, 4/20). Two percent of all pre-treatment EGFR-mutant lung cancers harbored an EGFR T790M mutation. Thirteen patients received erlotinib monotherapy as treatment for metastatic disease. The response rate was 8% (1/13, 95% confidence interval 0%-35%). For the patients who received erlotinib, the median progression-free survival was 2 months and the median overall survival was 16 months.

CONCLUSIONS

De novo EGFR T790M mutations are rare (<1%) when identified by standard sensitivity methods. TKI therapy for patients with baseline EGFR T790M detected by standard molecular analysis has limited benefit.

Differences in the survival of patients with recurrent versus de novo metastatic KRAS-mutant and EGFR-mutant lung adenocarcinomas

BACKGROUND

Prognostic variables are independently associated with survival and are fundamental to clinical trial design. In the current study, the authors evaluated the impact of stage of disease at the time of the initial diagnosis on overall survival (OS) in 2 independent, oncogene-defined cohorts.

METHODS

All patients with epidermal growth factor receptor (EGFR)-mutant and KRAS-mutant metastatic lung adenocarcinomas were identified through routine molecular testing from January 2005 through January 2011. Clinical characteristics were obtained. OS from the date of diagnosis of recurrent or de novo metastatic disease was estimated using the Kaplan-Meier method.

RESULTS

A total of 635 patients with KRAS-mutant and 496 patients with EGFR-mutant metastatic lung adenocarcinomas were identified. Among patients with KRAS-mutant lung adenocarcinomas, those with de novo metastatic disease were found to have a shorter median OS compared with those with recurrent metastatic disease (13 months vs 18 months; P = .003). In a multivariable analysis of patients with KRAS-mutant lung adenocarcinomas, de novo metastatic disease at the time of diagnosis (TNM stage IV vs stage I-III: hazard ratio, 1.5 [95% confidence interval, 1.2-1.8]; P<.001) was independently associated with shorter OS. In patients with EGFR-mutant lung adenocarcinomas, after controlling for age and Karnofsky performance status, de novo metastatic disease at the time of diagnosis (stage IV vs stage I-III: hazard ratio, 1.3 [95% confidence interval, 1.0-1.7]; P = .03) was found to be independently associated with shorter OS.

CONCLUSIONS

Among patients with KRAS-mutant lung adenocarcinomas, stage of disease at diagnosis was associated with OS from the time of diagnosis of recurrent/metastatic disease. In multivariable analyses, in both patients with EGFR-mutant and KRAS-mutant lung adenocarcinomas, advanced stage at the time of diagnosis was found to be independently associated with shorter survival. Stage at diagnosis is a prognostic variable that should be accounted for in prospective studies in patients with metastatic lung adenocarcinomas.

Opportunistic infections in patients treated with immunotherapy for cancer

Immunomodulatory antibodies that enhance the immune system to fight cancer are revolutionizing the treatment of patients with an expanding variety of malignancies. There is a unique spectrum of side effects associated with immunomodulatory antibodies, termed immune-related adverse events (irAEs), which include colitis and hepatitis among others. The treatment of refractory or severe irAEs can occasionally require significant immunosuppression, involving steroids or tumor necrosis factor-alpha antagonists, placing these patients at risk for infections. We present the first reported case to our knowledge of an opportunistic infection in a patient treated with an immunomodulatory antibody. As the use of immunomodulatory antibodies expands and more patients develop irAEs that require treatment with immunosuppression, recognition of the potential for opportunistic infections in this emerging patient population will be critical. Prospective trials are needed to define the optimal immunosuppressive management of irAEs and determine whether prophylactic antiviral, antibacterial, or antifungal therapies are beneficial in this unique population.

Pathological response after neoadjuvant chemotherapy in resectable non-small-cell lung cancers: proposal for the use of major pathological response as a surrogate endpoint

Improvements in outcomes for patients with resectable lung cancers have plateaued. Clinical trials of resectable non-small-cell lung cancers with overall survival as the primary endpoint require a decade or longer to complete, are expensive, and limit innovation. A surrogate for survival, such as pathological response to neoadjuvant chemotherapy, has the potential to improve the efficiency of trials and expedite advances. 10% or less residual viable tumour after neoadjuvant chemotherapy, termed here major pathological response, meets criteria for a surrogate; major pathological response strongly associates with improved survival, is reflective of treatment effect, and captures the magnitude of the treatment benefit on survival. We support the incorporation of major pathological response as a surrogate endpoint for survival in future neoadjuvant trials of resectable lung cancers. Additional prospective studies are needed to confirm the validity and reproducibility of major pathological response within individual histological and molecular subgroups and with new drugs.