Herbert M. Pinedo

Background: The programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) is used as a biomarker to predict benefit from immune checkpoint blockade (ICB) in patients with non-small cell lung cancer (NSCLC). However, additional biomarkers are needed. The potential of kinase activity profiling of peripheral blood mononuclear cells (PBMCs) for predicting response to ICB was previously shown in a discovery study. The goal of this prospective study is to evaluate the predictive value of blood-based kinase profiling for ICB response in patients with NSCLC and to compare the performance and added value to TPS. Methods: Advanced stage patients with NSCLC, treated with anti-programmed cell death protein 1 ICB (±chemotherapy) were included in this multicenter study (N=210 patients). PBMCs were collected prior to ICB treatment and profiled using a peptide microarray with multiple kinase substrates (PamChip). Classification analysis was performed to discriminate between patients with or without progressive disease by Response Evaluation Criteria in Solid Tumors (RECIST) V.1.1 <24 weeks after treatment start. A predictive model was first established based on TPS and kinase activity profiles. Subsequently, the performance of the model was tested in a second (validation) cohort. Results: In the validation cohort, a significantly higher progression-free survival (PFS) rate was observed for patients with predicted benefit than for patients without predicted benefit according to the kinome-based prediction model (HR=0.56, p=0.01), which tended better compared with TPS alone (HR=0.66, p=0.07). When the kinome-based model was combined with TPS, the difference in PFS between patients with and without predicted benefit was further increased (HR=0.38, p<0.001). PFS rates were also higher for patients with predicted benefit in subgroups with decreased PD-L1 expression (TPS <1% (HR=0.46, p=0.027) and TPS 1–50% (HR=0.20, p=0.005)). Conclusions: This study shows the predictive value of kinase activity profiling of PBMCs for ICB response in advanced NSCLC, which was superior compared with TPS. In particular, for patients with NSCLC with TPS <50%, combining TPS with the blood-based kinase test may identify patients with limited benefit from ICB. Trial registration number: NTR7015/NL6828.

Background Many cancer patients do not obtain clinical benefit from immune checkpoint inhibition. Checkpoint blockade targets T cells, suggesting that tyrosine kinase activity profiling of baseline peripheral blood mononuclear cells may predict clinical outcome. Methods Here a total of 160 patients with advanced melanoma or non-small-cell lung cancer (NSCLC), treated with anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) or anti-programmed cell death 1 (anti-PD-1), were divided into five discovery and cross-validation cohorts. The kinase activity profile was generated by analyzing phosphorylation of peripheral blood mononuclear cell lysates in a microarray comprising of 144 peptides derived from sites that are substrates for protein tyrosine kinases. Binary grouping into patients with or without clinical benefit was based on Response Evaluation Criteria in Solid Tumors V.1.1. Predictive models were trained using partial least square discriminant analysis (PLS-DA), performance of the models was evaluated by estimating the correct classification rate (CCR) using cross-validation. Results The kinase phosphorylation signatures segregated responders from non-responders by differences in canonical pathways governing T-cell migration, infiltration and co-stimulation. PLS-DA resulted in a CCR of 100% and 93% in the anti-CTLA-4 and anti-PD1 melanoma discovery cohorts, respectively. Cross-validation cohorts to estimate the accuracy of the predictive models showed CCRs of 83% for anti-CTLA-4 and 78% or 68% for anti-PD-1 in melanoma or NSCLC, respectively. Conclusion Blood-based kinase activity profiling for response prediction to immune checkpoint inhibitors in melanoma and NSCLC revealed increased kinase activity in pathways associated with T-cell function and led to a classification model with a highly accurate classification rate in cross-validation groups. The predictive value of kinase activity profiling is prospectively verified in an ongoing trial.

Local treatment with surgery and radiotherapy gives unsatisfactory results in patients with locally advanced cancer. In many cases distant metastases appear shortly after the removal of the primary tumor. Selecting breast cancer as a model for locally advanced disease, we are extrapolating our findings to other solid tumors. Neoadjuvant chemotherapy has improved survival of these patients by downstaging the primary tumors allowing local treatment and early elimination of distant micrometastases.We recently reported in this journal on a study of 42 patients with locally advanced breast cancer (LABC) who received prolonged neoadjuvant chemotherapy of doxorubicin, cyclophosphamide, and GM-CSF prior to surgery and postoperative radiotherapy. These results were promising and prompted us to initiate an international randomized phase III study in which either six neoadjuvant cycles or three neoadjuvant cycles plus three adjuvant cycles are being compared. In LABC patients treated with six neoadjuvant chemoimmunotherapy cycles, we observed a significant rise in the dendritic cell content of the axillary tumor-draining lymph nodes after therapy, associated with an encouraging disease free survival and overall survival. We hypothesize that the prolonged presence of draining lymph nodes in combination with the repeated tumor antigen release, dendritic cell recruitment, and activation may account for the observed increased survival of LABC patients. Based on our findings and the results of preclinical studies, we hypothesize that it is more effective to administer chemotherapy in an extended neoadjuvant regimen, taking advantage of the concurrent biological and immunological processes in the primary tumor and its draining lymph nodes.

The reversibility of cisplatin-protein interactions by the modulating agent WR2721, its active thiol-metabolite WR1065, and the symmetrical disulfide WR33278 was studied using the model compounds (Pt(diethylenetriammine) monofunctionally bound to the sulfur in glutathione (Pt(dien)SG) and Pt(diethylenetriammine) monofunctionally bound to the sulfur in S-methylglutathione (Pt(dien)SMeG). Both model compounds could be quantified by high-performance liquid chromatography (HPLC) with UV detection. The Pt-cysteine-like bond in Pt(dien)SG could not be reversed by any of the WR compounds or by the strong nucleophiles thiosulfate (TS) and diethyldithiocarbamate (DDTC). However, the Ptmethionine-like bond in Pt(dien)SMeG could be reversed by WR1065, although the reversal was slow (k₂=0.142m⁻¹ s⁻¹) as compared with that obtained using the modulating agents TS (k₂=10.1m⁻¹ s⁻¹) and DDTC (k₂=3.66m⁻¹ s⁻¹). WR2721 was hardly able to reverse the Pt-S bond in Pt(dien)SMeG (k₂=0.00529m⁻¹ s⁻¹), and WR33278 showed no capacity to do so. The activity ofcis-diamminedichloroplatinum(II) (CDDP)-inactivated fumarase was not appreciably restored by any of the WR compounds (16%, 7.7%, and 0 for 20mm WR1065, WR2721, and WR33278, respectively) in contrast to the strong nucleophile DDTC (61% for 2mm DDTC). These in vitro studies provide information at the molecular level that may explain why WR2721, in contrast to DDTC, does not provide protection against cisplatin-induced nephrotoxicity when it is given after platinum-containing chemotherapy. The results support the present clinical use of WR2721 prior to the administration of platinum compounds.