Oncogenic driver mutations in non-small cell lung cancer: Past, present and future

Results from a phase 1b study of telisotuzumab vedotin in combination with osimertinib in patients with c-Met protein-overexpressing, EGFR-mutated locally advanced/metastatic non-small cell lung cancer (NSCLC) after progression on prior osimertinib

BACKGROUND

Osimertinib is the standard first-line treatment for advanced epidermal growth factor receptor (EGFR)-mutated NSCLC. However, treatment resistance is inevitable and increased c-Met protein expression correlates with resistance. Telisotuzumab vedotin (Teliso-V) is an antibody-drug conjugate that targets c-Met protein overexpression. Herein, we report the results of a phase 1/1b trial evaluating Teliso-V plus osimertinib in patients with NSCLC after progression on osimertinib.

PATIENTS AND METHODS

This multicenter, open-label study (NCT02099058) enrolled patients with advanced EGFR-mutated, c-Met protein-overexpressing, non-squamous NSCLC that had progressed on prior osimertinib. Patients received Teliso-V (intravenously, every 2 weeks) plus osimertinib (orally, 80 mg once daily). Teliso-V was evaluated at 1.6 mg/kg in a safety lead-in phase and escalated to 1.9 mg/kg. Dose expansion included both doses. Endpoints included safety and tolerability, pharmacokinetics, objective response rate (ORR), duration of response (DOR), and progression-free survival (PFS).

RESULTS

A total of 38 patients received Teliso-V (1.6 mg/kg, n=20; 1.9 mg/kg, n=18) plus osimertinib and were included in this analysis. No dose-limiting toxicities were observed. Most frequent any-grade treatment-emergent adverse events (TEAEs) were peripheral sensory neuropathy (50%), peripheral edema (32%), and nausea (24%). Most common grade 3/4 TEAEs were anemia (11%) and pulmonary embolism (8%). Five TEAEs led to death; none were reported as being related to Teliso-V or osimertinib. The pharmacokinetic profile of Teliso-V plus osimertinib was similar to Teliso-V monotherapy. After a median follow-up of 7.4 months, ORR was 50.0% per independent central review (ICR) (DOR not reached), and median PFS per ICR was 7.4 months (95% CI: 5.4, NR).

CONCLUSIONS

Teliso-V plus osimertinib had promising activity and a manageable safety profile in patients with c-Met protein-overexpressing, EGFR-mutated non-squamous NSCLC after progression on osimertinib. This combination has the potential to address an unmet medical need in this patient population.

CLINICALTRIALS

GOV ID

NCT02099058.

Novel and potent MICA/B antibody is therapeutically effective in KRAS LKB1 mutant lung cancer models

BACKGROUND

Concurrent KRAS LKB1 (STK11, KL) mutant non-small cell lung cancers (NSCLC) do not respond well to current immune checkpoint blockade therapies, however targeting major histocompatibility complex class I-related chain A or B (MICA/B), could pose an alternative therapeutic strategy through activation of natural killer (NK) cells.

METHODS

Expression of NK cell activating ligands in NSCLC cell line and patient data were analyzed. Cell surface expression of MICA/B in NSCLC cell lines was determined through flow cytometry while ligand shedding in both patient blood and cell lines was determined through ELISA. We engineered an antibody-dependent cellular cytotoxicity (ADCC) enhanced MICA/B monoclonal antibody, AHA-1031, which prevents ligand shedding without interfering with binding to natural killer group 2D while targeting cancer cells via superior ADCC. We performed in vitro assays using ELISA and flow cytometry-based assays to confirm that our antibody potently binds to and stabilizes MICA/B expression across lung cancer and other solid tumor cell lines. Additionally, we used two KL mutant NSCLC cell lines and a KL mutant patient-derived xenograft (PDX) model to demonstrate in vivo antitumor efficacy and flow cytometry analysis for immune cell activation profiling.

RESULTS

NSCLC cell lines exhibit high MICA/B expression and secrete soluble MICA/B in vitro. Soluble MICA/B is also detected in patient blood samples. AHA-1031 binds to the α3 domain of MICA/B, preventing shedding and targeting tumor cells to ADCC. AHA-1031 exhibits high affinity and specificity to MICA/B, preventing MICA/B shedding in tumor lines and inducing ADCC in vitro. Our antibody also effectively binds and stabilizes MICA/B expression in additional tumor types and demonstrates broad specificity. We show that in two KL mutant NSCLC xenograft models and a KL mutant PDX model, treatment with AHA-1031 monotherapy significantly inhibits tumor growth compared with vehicle-treated animals with no observable toxicity. Tumor tissues from treated mice exhibit significantly increased immune cell infiltrates and activated NK cell populations.

CONCLUSIONS

Activating NK cells through MICA/B stabilization and inducing ADCC offers an alternative and potent therapy option in KL tumors. MICA/B are shed across different tumors making this therapeutic strategy universally applicable.

Reprogramming tumor-associated macrophages: The role of MEK-STAT3 inhibition in lung cancer

Tumor-associated macrophages (TAMs) crucially contribute to lung cancer's advancement and escape from the immune system. TAMs, particularly the M2 phenotype, promote an immunosuppressive microenvironment, facilitating tumor growth and metastasis. The MEK-STAT3 signalling pathway is a critical mediator in this process, driving TAM reprogramming and contributing to lung cancer's resistance to treatment. Inhibiting the MEK and STAT3 pathways disrupts key cancer-promoting mechanisms, including immune evasion, angiogenesis, and metastasis. Preclinical studies have demonstrated the effectiveness of MEK inhibitors, such as trametinib and selumetinib, in synergistic therapies for NSCLC, particularly in modulating the tumor microenvironment. We analyse the present understanding of approaches that can transform TAMs via the inhibition of MEK-STAT3 with either solo or combined treatments in lung cancer therapy.

S6K1 is a Targetable Vulnerability in Tumors Exhibiting Plasticity and Therapy Resistance

Background: Most tumors initially respond to treatment, yet refractory clones subsequently develop owing to resistance mechanisms associated with cancer cell plasticity and heterogeneity. Methods: We used a chemical biology approach to identify protein targets in cancer cells exhibiting diverse driver mutations and representing models of tumor lineage plasticity and therapy resistance. An unbiased screen of a drug library was performed against cancer cells followed by synthesis of chemical analogs of the most effective drug. The cancer subtype target range of the leading drug was determined by PRISM analysis of over 900 cancer cell lines at the Broad Institute, MA. RNA-sequencing and enrichment analysis of differentially expressed genes, as well as computational molecular modeling and pull-down with biotinylated small molecules were used to identify and validate RPS6KB1 (p70S6K or S6K1) as an essential target. Genetic restoration was used to test the functional role of S6K1 in cell culture and xenograft models. Results: We identified a novel derivative of the antihistamine drug ebastine, designated Super-ebastine (Super-EBS), that inhibited the viability of cancer cells representing diverse KRAS and EGFR driver mutations and models of plasticity and treatment resistance. Interestingly, PRISM analysis indicated that over 95% of the diverse cancer cell lines tested were sensitive to Super-EBS and the predicted target was the serine/threonine kinase S6K1. S6K1 is upregulated in various cancers relative to counterpart normal/benign tissues and phosphorylated-S6K1 predicts poor prognosis for cancer patients. We noted that inhibition of S6K1 phosphorylation was necessary for tumor cell growth inhibition, and restoration of phospho-S6K1 rendered tumor cells resistant to Super-EBS. Inhibition of S6K1 phosphorylation by Super-EBS induced caspase-2 dependent apoptosis via inhibition of the Cdc42/Rac-1/p-PAK1 pathway that led to actin depolymerization and caspase-2 activation. The essential role of S6K1 in the action of Super-EBS was recapitulated in xenografts, and knockout of S6K1 abrogated tumor growth in mice. Conclusion: S6K1 is a therapeutic vulnerability in tumors exhibiting intrinsic and/or acquired resistance to treatment.