Increase in serum choline levels predicts for improved progression-free survival (PFS) in patients with advanced cancers receiving pembrolizumab.

BACKGROUND: Recent studies have demonstrated that T cells can induce vasodilation in a choline-acetyltransferase dependent manner, leading to an increase in T cell migration to infected tissues in response to viral infection, but its role in cancer is unclear. Choline acetyltransferase catalyzes the production of acetylcholine from choline and acetyl-CoA, however, acetylcholine is challenging to quantify due to its extremely short half-life while choline is stable. This study aims to correlate serum choline levels in patients with advanced solid tumors receiving pembrolizumab with treatment outcomes. METHODS: Blood samples were collected at baseline and at week 7 (pre-cycle 3) in patients treated with pembrolizumab in the INvestigator-initiated Phase 2 Study of Pembrolizumab Immunological Response Evaluation phase II trial (NCT02644369). Samples were analyzed for choline and circulating tumor DNA (ctDNA). Multivariable Cox models were used to assess the association between choline and overall survival (OS) and progression-free survival (PFS) when including ΔctDNAC3 (the change in ctDNA from baseline to cycle 3), cohort, PD-L1 expression and tumor mutation burden (TMB). An independent validation cohort from the LIBERATE study (NCT03702309) included patients on early phase trials treated with a PD-1 inhibitor. RESULTS: A total of 106 pts were included in the analysis. With a median follow-up of 12.6 months, median PFS and OS were 1.9 and 13.7 months, respectively. An increase in serum choline level at week 7 compared with baseline (ΔcholineC3) in 81 pts was significantly associated with a better PFS (aHR 0.48, 95% CI 0.28 to 0.83, p=0.009), and a trend toward a better OS (aHR 0.64, 95% CI 0.37 to 1.12, p=0.119). A combination of ΔctDNAC3 and ΔcholineC3 was prognostic for both OS and PFS. Multivariable analyses show ΔcholineC3 was a prognostic factor for PFS independent of ΔctDNAC3, cohort, PD-L1 and TMB. In the independent validation cohort (n=51), an increase in serum choline at cycle 2 was associated with a trend to improved PFS. CONCLUSIONS: This is the first exploratory report of serum choline levels in pan-cancer patients receiving pembrolizumab. The association between improved PFS and ΔcholineC3 suggests a possible role for the cholinergic system in the regulation of antitumor immunity. Further pre-clinical and clinical studies are required to validate this finding. TRIAL REGISTRATION NUMBER: NCT03702309.

Novel strategies in immune checkpoint inhibitor drug development: How far are we from the paradigm shift?

The development of immune checkpoint inhibitors (ICI) represents a major milestone in immune-oncology. Over the years these agents have demonstrated efficacy in an increasing array of malignancies. Despite this success however, significant challenges remain. Novel approaches to both drug development and trial design are required to incorporate the unique pharmacokinetic and pharmacodynamic properties of ICIs. Further, it has also been established that the benefit of ICIs is limited to only a subset of patients. The molecular interactions between native immune cells and tumorigenesis and progression represent an active area of biomarker research, and elucidating the mechanisms of response and resistance is crucial to develop rational trial designs for the next wave of immune-oncology (IO) clinical trials, particularly in patients with primary and/or acquired resistance. Efforts are now being made to integrate both biological and clinical information using novel multi-omic approaches which are now being developed to further elucidate the molecular signatures associated with IO treatment response and resistance and enable rational drug development and trial design processes. As such, precision IO and the ability to deliver patient-specific choices for ICI monotherapies or combination therapies has become an increasingly tangible goal. We herein describe the current landscape in ICI drug development and discuss the challenges and future directions in this exciting and evolving era in immune-oncology.

Real-World Experience of Palbociclib-Induced Adverse Events and Compliance With Complete Blood Count Monitoring in Women With Hormone Receptor-Positive/HER2-Negative Metastatic Breast Cancer.

BACKGROUND: The cyclin-dependent kinase 4/6 inhibitor palbociclib has emerged as a novel therapeutic agent in metastatic breast cancer. Neutropenia is commonly observed, and thus stringent treatment guidelines regarding complete blood count (CBC) monitoring have been developed. The aim of this study was to provide a real-world experience of the toxicities associated with palbociclib therapy and to evaluate compliance with CBC monitoring. PATIENTS AND METHODS: We performed a retrospective single-center audit of hormone receptor-positive metastatic breast cancer patients treated with palbociclib over a 6-month period in an Irish tertiary referral hospital. RESULTS: A total of 64 patients were included in the analysis. Palbociclib was most commonly used in combination with letrozole (n = 40). A total of 28 patients (44%; 95% confidence interval, 31.2-56.2) had treatment deferrals due to neutropenia, with a median time to first deferral of 4 weeks. Fifteen patients (23%; 95% confidence interval, 15.4-37.7) required dose adjustments; however, there was no association with an increased risk of progressive disease (P = .56). Only 3 patients discontinued treatment as a result of poor tolerance. Adverse events were as expected; however, 7 venous thromboembolic events were reported. CONCLUSION: Compliance was good with existing CBC monitoring guidelines. We observed an 11% incidence of venous thromboembolic events, a significant increase from 2% reported in the PALOMA-3 trial. Further studies are recommended to determine if prophylactic anticoagulation may benefit these patients.

Evaluating the Time to Palliative Care Referrals in Patients With Small-Cell Lung Cancer: A Single-Centre Retrospective Review.

INTRODUCTION: Lung cancer is a leading cause of morbidity and mortality worldwide. Patients with lung cancer may experience a plethora of symptoms, which can be debilitating and affect their quality of life. Palliative care input to manage their physical and psychological well-being is a crucial component of their oncological care. The benefit of early palliative care input has been shown in patients with non-small cell lung cancer; however, data pertaining to patients with small-cell lung cancer are scarce. Nevertheless, early palliative care input is recommended by several national and international guidelines. Thus, we aimed to assess the time to palliative care referrals in patients diagnosed with small-cell lung cancer in an Irish tertiary hospital and to determine what impact this had on overall survival. METHODS: We performed a retrospective, single-center audit of all patients diagnosed with extensive stage small-cell lung cancer over a 6-year period in an Irish tertiary hospital. RESULTS: Overall, 91 patients were identified. Median age at diagnosis was 66 years (range: 38-83 years). The median Eastern Cooperative Oncology Group Performance Status at diagnosis was 1 (range: 0-3); 24 (26%) patients had multiple sites of distant metastasis at diagnosis; 45 (49.5%) patients were alive at 6 months, and 15 (16.5%) patients were alive at 12 months. One hundred percent of patients received palliative care input in our center over the course of their care. In the patients alive at 6 months after diagnosis, there was no survival advantage in those receiving palliative care within 1 month ( P = .002, odd ratio: 0.23, 95% confidence interval: 0.09-0.59). CONCLUSION: Palliative care treatment is a critical aspect in the oncological treatment of all patients diagnosed with advanced cancer, and this study highlights good compliance with existing national guidelines. Further research focusing on quality-of-life issues with the use of questionnaires to assess physical and psychological symptoms should be performed to further understand the impact of palliative care in these patients.

Migrating Polyarthritis as a Feature of Occult Malignancy: 2 Case Reports and a Review of the Literature.

Malignant disease may be associated with a wide variety of musculoskeletal syndromes. Rarely the musculoskeletal system can be indirectly affected by paraneoplastic phenomena, such as carcinomatous polyarthritis (CP). The differential diagnosis for CP is broad and is often a diagnosis of exclusion. CP often presents similarly to other forms of inflammatory arthritis, and a detailed history and physical examination can often distinguish CP from other more common causes of polyarticular arthritis. However serological tests such as rheumatoid factor (RF) and anti-citrullinated peptide (anti-CCP) antibody positivity, while rare, can be misleading. Clinical awareness and suspicion are paramount in achieving an accurate diagnosis and early detection of an occult neoplasm is critical for prompt management and therapy. We report two cases presenting with this unique clinical phenotype associated with paraneoplastic polyarthropathy and review the literature.