Fulvestrant and everolimus efficacy after CDK4/6 inhibitor: a prospective study with circulating tumor DNA analysis

In a prospective study (NCT02866149), we assessed the efficacy of fulvestrant and everolimus in CDK4/6i pre-treated mBC patients and circulating tumor DNA (ctDNA) changes throughout therapy. Patients treated with fulvestrant and everolimus had their ctDNA assessed at baseline, after 3-5 weeks and at disease progression. Somatic mutations were identified in archived tumor tissues by targeted NGS and tracked in cell-free DNA by droplet digital PCR. ctDNA detection was then associated with clinicopathological characteristics and patients' progression-free survival (PFS), overall survival (OS) and best overall response (BOR). In the 57 included patients, median PFS and OS were 6.8 (95%CI [5.03-11.5]) and 38.2 (95%CI [30.0-not reached]) months, respectively. In 47 response-evaluable patients, BOR was a partial response or stable disease in 15 (31.9%) and 11 (23.4%) patients, respectively. Among patients with trackable somatic mutation and available plasma sample, N = 33/47 (70.2%) and N = 19/36 (52.8%) had ctDNA detected at baseline and at 3 weeks, respectively. ctDNA detection at baseline and PIK3CA mutation had an adverse prognostic impact on PFS and OS in multivariate analysis. This prospective cohort study documents the efficacy of fulvestrant and everolimus in CDK4/6i-pretreated ER + /HER2- mBC and highlights the clinical validity of early ctDNA changes as pharmacodynamic biomarker.

Long response to immune checkpoint inhibitors in metastatic NSCLC despite EGFR germline mutation. A case report

First-line therapy in advanced non-small-cell-lung-cancer (NSCLC) is based on chemotherapy except for patients with a tumor proportion score for programmed death ligand 1 (PD-L1) of 50% or greater, pembrolizumab is administrated. However, patients with somatic-EGFR-mutated tumors had usually been excluded from clinical applications of immune checkpoint inhibitors (ICIs). Germline-EGFR-mutated-patients are known to not respond to EGFR-Tyrosine-Kinase-inhibitors (TKIs). But what about germline EGFR mutations and response to ICIs? Herein, we describe the case of a long response to ICIs treatment in a complex metastatic NSCLC with co-occuring EGFR germline and KRAS somatic mutations, high PD-L1 score and a smoking history.

Phase II study of intrathecal administration of trastuzumab in patients with HER2-positive breast cancer with leptomeningeal metastasis

BACKGROUND

Patients with HER2-positive breast cancer (HER2 + BC) develop central nervous system metastases twice as often as patients with luminal HER2-negative breast cancer. Leptomeningeal progression results in a drastically altered prognosis with limited therapeutic options. This phase II study was conducted to assess the efficacy of intrathecal (IT) trastuzumab in HER2 + BC patients with leptomeningeal metastasis (LM), based on a phase I dose-escalation study that had determined the recommended weekly dose of 150 mg for phase II.

METHODS

Eligible patients received weekly administrations of 150 mg of IT trastuzumab. The primary endpoint was clinical neurologic progression-free survival (LM-related-PFS) after 8 weeks. Overall survival (OS), toxicities, and quality of life (QoL) were secondary endpoints.

RESULTS

Among the 19 enrolled patients, 16 (84%) had concomitant brain metastases, 15 of them had received prior radiotherapy to the brain. All patients had received at least one line of systemic anti-HER2 therapy. After 8 weeks, 14 patients (74%) were free of neurological progression. The median LM-related-PFS was 5.9 months and the median OS was 7.9 months. According to the QLQ-C30 and BN20 scales, the global health-related QoL status seemed preserved and no toxicity above grade 3 was observed.

CONCLUSIONS

Conducting studies on patients with LM poses significant challenges and ethical dilemmas inherent to this population. Despite some limits, this phase II study's findings in terms of clinical neurologic response and QoL's control confirms weekly administration of 150 mg of IT trastuzumab as a valuable option for HER + BC patients with LM and support the interest for further investigations.

Standardisation of pathogenicity classification for somatic alterations in solid tumours and haematologic malignancies

BACKGROUND

The difficulty in interpreting somatic alterations is correlated with the increase in sequencing panel size. To correctly guide the clinical management of patients with cancer, there needs to be accurate classification of pathogenicity followed by actionability assessment. Here, we describe a specific detailed workflow for the classification of the pathogenicity of somatic variants in cancer into five categories: benign, likely benign, unknown significance, likely pathogenic and pathogenic.

METHODS

Classification is obtained by combining a set of eight relevant criteria in favour of either a pathogenic or a benign effect (pathogenic stand-alone, pathogenic very strong, pathogenic strong, pathogenic moderate, pathogenic supporting, benign supporting, benign strong and benign stand-alone).

RESULTS

Our guide is concordant with the ACMG/AMP 2015 guidelines for germline variants. Interpretation of somatic variants requires considering specific criteria, such as the disease and therapeutic context, co-occurring genomic events in the tumour when available and the use of cancer-specific variant databases. In addition, the gene role in tumorigenesis (oncogene or tumour suppressor gene) also needs to be taken into consideration.

CONCLUSION

Our classification could contribute to homogenize best practices on somatic variant pathogenicity interpretation and improve interpretation consistency both within and between laboratories.