Circadian Regulation of Drug Responses: Toward Sex-Specific and Personalized Chronotherapy.

Today's challenge for precision medicine involves the integration of the impact of molecular clocks on drug pharmacokinetics, toxicity, and efficacy toward personalized chronotherapy. Meaningful improvements of tolerability and/or efficacy of medications through proper administration timing have been confirmed over the past decade for immunotherapy and chemotherapy against cancer, as well as for commonly used pharmacological agents in cardiovascular, metabolic, inflammatory, and neurological conditions. Experimental and human studies have recently revealed sexually dimorphic circadian drug responses. Dedicated randomized clinical trials should now aim to issue personalized circadian timing recommendations for daily medical practice, integrating innovative technologies for remote longitudinal monitoring of circadian metrics, statistical prediction of molecular clock function from single-timepoint biopsies, and multiscale biorhythmic mathematical modelling. Importantly, chronofit patients with a robust circadian function, who would benefit most from personalized chronotherapy, need to be identified. Conversely, nonchronofit patients could benefit from the emerging pharmacological class of chronobiotics targeting the circadian clock.

Why does circadian timing of administration matter for immune checkpoint inhibitors' efficacy?

BACKGROUND: Tolerability and antitumour efficacy of chemotherapy and radiation therapy can vary largely according to their time of administration along the 24-h time scale, due to the moderation of their molecular and cellular mechanisms by circadian rhythms. Recent clinical data have highlighted a striking role of dosing time for cancer immunotherapy, thus calling for a critical evaluation. METHODS: Here, we review the clinical data and we analyse the mechanisms through which circadian rhythms can influence outcomes on ICI therapies. We examine how circadian rhythm disorders can affect tumour immune microenvironment, as a main mechanism linking the circadian clock to the 24-h cycles in ICIs antitumour efficacy. RESULTS: Real-life data from 18 retrospective studies have revealed that early time-of-day (ToD) infusion of immune checkpoint inhibitors (ICIs) could enhance progression-free and/or overall survival up to fourfold compared to late ToD dosing. The studies involved a total of 3250 patients with metastatic melanoma, lung, kidney, bladder, oesophageal, stomach or liver cancer from 9 countries. Such large and consistent differences in ToD effects on outcomes could only result from a previously ignored robust chronobiological mechanism. The circadian timing system coordinates cellular, tissue and whole-body physiology along the 24-h timescale. Circadian rhythms are generated at the cellular level by a molecular clock system that involves 15 specific clock genes. The disruption of circadian rhythms can trigger or accelerate carcinogenesis, and contribute to cancer treatment failure, possibly through tumour immune evasion resulting from immunosuppressive tumour microenvironment. CONCLUSIONS AND PERSPECTIVE: Such emerging understanding of circadian rhythms regulation of antitumour immunity now calls for randomised clinical trials of ICIs timing to establish recommendations for personalised chrono-immunotherapies with current and forthcoming drugs.

GATEKEEPER's Strategy for the Multinational Large-Scale Piloting of an eHealth Platform: Tutorial on How to Identify Relevant Settings and Use Cases.

BACKGROUND: The World Health Organization's strategy toward healthy aging fosters person-centered integrated care sustained by eHealth systems. However, there is a need for standardized frameworks or platforms accommodating and interconnecting multiple of these systems while ensuring secure, relevant, fair, trust-based data sharing and use. The H2020 project GATEKEEPER aims to implement and test an open-source, European, standard-based, interoperable, and secure framework serving broad populations of aging citizens with heterogeneous health needs. OBJECTIVE: We aim to describe the rationale for the selection of an optimal group of settings for the multinational large-scale piloting of the GATEKEEPER platform. METHODS: The selection of implementation sites and reference use cases (RUCs) was based on the adoption of a double stratification pyramid reflecting the overall health of target populations and the intensity of proposed interventions; the identification of a principles guiding implementation site selection; and the elaboration of guidelines for RUC selection, ensuring clinical relevance and scientific excellence while covering the whole spectrum of citizen complexities and intervention intensities. RESULTS: Seven European countries were selected, covering Europe's geographical and socioeconomic heterogeneity: Cyprus, Germany, Greece, Italy, Poland, Spain, and the United Kingdom. These were complemented by the following 3 Asian pilots: Hong Kong, Singapore, and Taiwan. Implementation sites consisted of local ecosystems, including health care organizations and partners from industry, civil society, academia, and government, prioritizing the highly rated European Innovation Partnership on Active and Healthy Aging reference sites. RUCs covered the whole spectrum of chronic diseases, citizen complexities, and intervention intensities while privileging clinical relevance and scientific rigor. These included lifestyle-related early detection and interventions, using artificial intelligence-based digital coaches to promote healthy lifestyle and delay the onset or worsening of chronic diseases in healthy citizens; chronic obstructive pulmonary disease and heart failure decompensations management, proposing integrated care management based on advanced wearable monitoring and machine learning (ML) to predict decompensations; management of glycemic status in diabetes mellitus, based on beat to beat monitoring and short-term ML-based prediction of glycemic dynamics; treatment decision support systems for Parkinson disease, continuously monitoring motor and nonmotor complications to trigger enhanced treatment strategies; primary and secondary stroke prevention, using a coaching app and educational simulations with virtual and augmented reality; management of multimorbid older patients or patients with cancer, exploring novel chronic care models based on digital coaching, and advanced monitoring and ML; high blood pressure management, with ML-based predictions based on different intensities of monitoring through self-managed apps; and COVID-19 management, with integrated management tools limiting physical contact among actors. CONCLUSIONS: This paper provides a methodology for selecting adequate settings for the large-scale piloting of eHealth frameworks and exemplifies with the decisions taken in GATEKEEPER the current views of the WHO and European Commission while moving forward toward a European Data Space.

Efficacy and safety of chronomodulated irinotecan, oxaliplatin, 5-fluorouracil and leucovorin combination as first- or second-line treatment against metastatic colorectal cancer: Results from the International EORTC 05011 Trial.

The triplet combination of irinotecan, oxaliplatin and fluorouracil is an active frontline regimen in metastatic colorectal cancer, but scarce data exist on its use as salvage treatment. We aimed at assessing its safety and efficacy profiles with its circadian-based administration (chronoIFLO5) as either first- or second-line treatment, within the time-finding EORTC 05011 trial. Five-day chronoIFLO5 was administered every 3 weeks in patients with PS 0, 1 or 2. It consisted of chronomodulated irinotecan (180 mg/sqm), oxaliplatin (80 mg/sqm) and fluorouracil-leucovorin (2800 and 1200 mg/sqm, respectively). For our study, toxicity and antitumour activity were evaluated separately in first- and second-line settings. Primary endpoints included Grade 3-4 toxicity rates, best objective response rate (ORR), progression-free survival (PFS) and overall survival (OS). One-hundred forty-nine and 44 patients were treated in first-line and second-line settings, respectively, with a total of 1138 cycles with median relative dose intensities of about 90%. Demographics were comparable in the two groups. Thirty-six (24.7%) and 10 (22.2%) patients experienced at least one episode of severe toxicity in first line and second line, respectively. Frontline chronoIFLO5 yielded an ORR of 62.3% [95% CI: 54.2-70.4] and resulted in median PFS and OS of 8.7 months [7.5-9.9] and 19.9 months [15.4-24.5]. Corresponding figures in second line were 37.5% [22.5-52.5], 6.7 months [4.8-8.9] and 16.3 months [11.8-20.8]. International and prospective evaluation revealed the favourable safety and efficacy profiles of chronoIFLO5, both as frontline and as salvage treatment against metastatic colorectal cancer. In particular, encouraging activity in second line was observed, with limited haematological toxicity.

Optimizing circadian drug infusion schedules towards personalized cancer chronotherapy.

Precision medicine requires accurate technologies for drug administration and proper systems pharmacology approaches for patient data analysis. Here, plasma pharmacokinetics (PK) data of the OPTILIV trial in which cancer patients received oxaliplatin, 5-fluorouracil and irinotecan via chronomodulated schedules delivered by an infusion pump into the hepatic artery were mathematically investigated. A pump-to-patient model was designed in order to accurately represent the drug solution dynamics from the pump to the patient blood. It was connected to semi-mechanistic PK models to analyse inter-patient variability in PK parameters. Large time delays of up to 1h41 between the actual pump start and the time of drug detection in patient blood was predicted by the model and confirmed by PK data. Sudden delivery spike in the patient artery due to glucose rinse after drug administration accounted for up to 10.7% of the total drug dose. New model-guided delivery profiles were designed to precisely lead to the drug exposure intended by clinicians. Next, the complete mathematical framework achieved a very good fit to individual time-concentration PK profiles and concluded that inter-subject differences in PK parameters was the lowest for irinotecan, intermediate for oxaliplatin and the largest for 5-fluorouracil. Clustering patients according to their PK parameter values revealed patient subgroups for each drug in which inter-patient variability was largely decreased compared to that in the total population. This study provides a complete mathematical framework to optimize drug infusion pumps and inform on inter-patient PK variability, a step towards precise and personalized cancer chronotherapy.

Evaluation and Management of Sleep and Circadian Rhythm Disturbance in Cancer.

OPINION STATEMENT: Sleep and circadian rhythm disturbance are among the most commonly experienced symptoms in patients with cancer. These disturbances occur throughout the spectrum of cancer care from diagnosis, treatment, and long into survivorship. The pathogenesis of these symptoms and disturbances is based on common inflammatory pathways related to cancer and its' treatments. The evaluation of sleep and circadian disorders requires an understanding of how these symptoms cluster with other cancer-related symptoms and potentiate each other. A thorough evaluation of these symptoms and disorders utilizing validated diagnostic tools, directed review of clinical information, and diagnostic testing is recommended. Treatment of sleep and circadian disturbance in cancer patients should be based on the findings of a detailed evaluation, including specific treatment of primary sleep and circadian disorders, and utilize integrative and personalised management of cancer-related symptoms through multiple pharmacologic and non-pharmacologic modalities. Recognition, evaluation, and treatment of sleep and circadian rhythm disturbance in cancer may lead to improved symptom management, quality of life, and outcomes.

Impact of assessment frequency of patient-reported outcomes: an observational study using an eHealth platform in cancer patients.

BACKGROUND AND AIM: The evaluation of patient-reported outcomes (PRO) in cancer has proven relevant positive clinical impact on patients' communication with healthcare professionals, decision-making for management, well-being, and overall survival. However, the optimal frequency of PRO assessment has yet to be defined. Based on the assumption that more frequent sampling would enhance accuracy, we aimed at identifying the optimal sampling frequency that does not miss clinically relevant insight. METHODS: We used pilot data from 31 advanced cancer patients who completed once daily the 19-item MD Anderson Symptom Inventory at home. The resulting dataset allowed us to compare different PRO assessment frequencies to daily sampling, i.e., alternate days (q2d), every third day (q3d), or once a week (q1w). We evaluated the sampling frequencies for two main outcomes: average symptom intensity and identification of severe symptoms. RESULTS: The majority of the differences between corresponding averages of daily data and those for q2d, q3d, and q1w datasets were close to 0, yet the extremes exceeded 5. Clinically meaningful differences, i.e., > 1, were observed in 0.76% of patient items for q2d, in 2.72% for q3d, and in 11.93% for q1w. Moreover, median values of missed instances of a severe symptom (i.e., > 6) were 14.6% for q2d, 27.8% for q3d, and 55.6% for q1w. CONCLUSIONS: Our analysis suggests that in patients receiving chemotherapy for advanced cancer, increasing the density of PRO collection enhances the accuracy of PRO assessment to a clinically meaningful extent. This is valid for both computations of averages symptom burden and for the recognition of episodes of severe symptom intensity.

A retrospective study of patient-tailored FOLFIRINOX as a first-line chemotherapy for patients with advanced biliary tract cancer.

BACKGROUND: FOLFIRINOX is a pillar first-line regimen in the treatment of pancreatic cancer. Historically, biliary tract cancer (BTC) and pancreatic cancer have been treated similarly with gemcitabine alone or combined with a platinum compound. With growing evidence supporting the role of fluoropyrimidines in the treatment of BTC, we aimed at assessing the outcomes of patients (pts) with BTC on frontline FOLFIRINOX. METHODS: We retrospectively analyzed data of all our consecutive patients with locally advanced (LA) or metastatic (M) BTC who were registered to receive FOLFIRINOX as a first-line therapy between 12/2013 and 11/2017 at Paul Brousse university hospital. The main endpoints were Overall Survival (OS), Time-to-Progression (TTP), best Objective Response Rate (ORR), Disease Control rate (DCR), secondary macroscopically-complete resection (res) and incidence of severe (grade 3-4) toxicity (tox). RESULTS: There were 17 male (40%) and 25 female (60%) pts. aged 36 to 84 years (median: 67). They had PS of 0 (55%) or 1 (45%), and intrahepatic cholangiocarcinoma (CCA) (21 pts., 50%), gallbladder carcinoma (8 pts., 19%), perihilar CCA (7 pts., 17%), distal CCA (4 pts., 10%) and ampulloma (2 pts., 5%). BTC was LA or M in 10 (24%) and 32 pts. (76%) respectively. Biliary stent was placed in 14 pts. (33%). A median of 10 courses was given with median treatment duration of 6 months. There were no untoward toxicity issues, with no febrile neutropenia, emergency admission for toxicity or toxic death. We observed 12 partial responses (29%) and 19 disease stabilisations (45%). Six patients (14%) underwent secondary R0-R1 resection. Median TTP was 8 months [95%CL, 6-10] and median OS was 15 months [13-17]. Patients undergoing secondary resection displayed a 3-y disease-free rate of 83%. CONCLUSIONS: First-line FOLFIRINOX offers promising results in patients with LA and M-BTC. It deserves prospective evaluation to further improve outcomes for advanced BTC.

Systems Chronotherapeutics.

Chronotherapeutics aim at treating illnesses according to the endogenous biologic rhythms, which moderate xenobiotic metabolism and cellular drug response. The molecular clocks present in individual cells involve approximately fifteen clock genes interconnected in regulatory feedback loops. They are coordinated by the suprachiasmatic nuclei, a hypothalamic pacemaker, which also adjusts the circadian rhythms to environmental cycles. As a result, many mechanisms of diseases and drug effects are controlled by the circadian timing system. Thus, the tolerability of nearly 500 medications varies by up to fivefold according to circadian scheduling, both in experimental models and/or patients. Moreover, treatment itself disrupted, maintained, or improved the circadian timing system as a function of drug timing. Improved patient outcomes on circadian-based treatments (chronotherapy) have been demonstrated in randomized clinical trials, especially for cancer and inflammatory diseases. However, recent technological advances have highlighted large interpatient differences in circadian functions resulting in significant variability in chronotherapy response. Such findings advocate for the advancement of personalized chronotherapeutics through interdisciplinary systems approaches. Thus, the combination of mathematical, statistical, technological, experimental, and clinical expertise is now shaping the development of dedicated devices and diagnostic and delivery algorithms enabling treatment individualization. In particular, multiscale systems chronopharmacology approaches currently combine mathematical modeling based on cellular and whole-body physiology to preclinical and clinical investigations toward the design of patient-tailored chronotherapies. We review recent systems research works aiming to the individualization of disease treatment, with emphasis on both cancer management and circadian timing system-resetting strategies for improving chronic disease control and patient outcomes.

Relevance of a Mobile Internet Platform for Capturing Inter- and Intrasubject Variabilities in Circadian Coordination During Daily Routine: Pilot Study.

BACKGROUND: Experimental and epidemiologic studies have shown that circadian clocks' disruption can play an important role in the development of cancer and metabolic diseases. The cellular clocks outside the brain are effectively coordinated by the body temperature rhythm. We hypothesized that concurrent measurements of body temperature and rest-activity rhythms would assess circadian clocks coordination in individual patients, thus enabling the integration of biological rhythms into precision medicine. OBJECTIVE: The objective was to evaluate the circadian clocks' coordination in healthy subjects and patients through simultaneous measurements of rest-activity and body temperature rhythms. METHODS: Noninvasive real-time measurements of rest-activity and chest temperature rhythms were recorded during the subject's daily life, using a dedicated new mobile electronic health platform (PiCADo). It involved a chest sensor that jointly measured accelerations, 3D orientation, and skin surface temperature every 1-5 min and relayed them out to a mobile gateway via Bluetooth Low Energy. The gateway tele-transmitted all stored data to a server via General Packet Radio Service every 24 hours. The technical capabilities of PiCADo were validated in 55 healthy subjects and 12 cancer patients, whose rhythms were e-monitored during their daily routine for 3-30 days. Spectral analyses enabled to compute rhythm parameters values, with their 90% confidence limits, and their dynamics in each subject. RESULTS: All the individuals displayed a dominant circadian rhythm in activity with maxima occurring from 12:09 to 20:25. This was not the case for the dominant temperature period, which clustered around 24 hours for 51 out of 67 subjects (76%), and around 12 hours for 13 others (19%). Statistically significant sex- and age-related differences in circadian coordination were identified in the noncancerous subjects, based upon the range of variations in temperature rhythm amplitudes, maxima (acrophases), and phase relations with rest-activity. The circadian acrophase of chest temperature was located at night for the majority of people, but it occurred at daytime for 26% (14/55) of the noncancerous people and 33% (4/12) of the cancer patients, thus supporting important intersubject differences in circadian coordination. Sex, age, and cancer significantly impacted the circadian coordination of both rhythms, based on their phase relationships. CONCLUSIONS: Complementing rest-activity with chest temperature circadian e-monitoring revealed striking intersubject differences regarding human circadian clocks' coordination and timing during daily routine. To further delineate the clinical importance of such finding, the PiCADo platform is currently applied for both the assessment of health effects resulting from atypical work schedules and the identification of the key determinants of circadian disruption in cancer patients.

Systems Biology, Systems Medicine, Systems Pharmacology: The What and The Why.

Systems biology is today such a widespread discipline that it becomes difficult to propose a clear definition of what it really is. For some, it remains restricted to the genomic field. For many, it designates the integrated approach or the corpus of computational methods employed to handle the vast amount of biological or medical data and investigate the complexity of the living. Although defining systems biology might be difficult, on the other hand its purpose is clear: systems biology, with its emerging subfields systems medicine and systems pharmacology, clearly aims at making sense of complex observations/experimental and clinical datasets to improve our understanding of diseases and their treatments without putting aside the context in which they appear and develop. In this short review, we aim to specifically focus on these new subfields with the new theoretical tools and approaches that were developed in the context of cancer. Systems pharmacology and medicine now give hope for major improvements in cancer therapy, making personalized medicine closer to reality. As we will see, the current challenge is to be able to improve the clinical practice according to the paradigm shift of systems sciences.

Relationship between subjective and actigraphy-measured sleep in 237 patients with metastatic colorectal cancer.

OBJECTIVE: Patients with cancers frequently experience sleep and circadian dysfunction. To date, only a few studies have used both a questionnaire and actigraphy for concomitant evaluation of sleep and circadian function in patients with cancer. We sought to evaluate objective sleep and circadian parameters in metastatic colon cancer (MCC) patients and their associations with symptoms and quality of life (QOL). METHODS: Patients reported subjective sleep problems on the EORTC QLQ-C30. Sleep and circadian parameters were calculated using a wrist-actigraph that patients wore for 72 h. RESULTS: 237 Patients with MCC (mean age: 60.4 years; range: 20.7-77.6; Male/Female ratio: 1.66) participated in this cross-sectional study. Subjective sleep problems were reported by 63.4% of patients (S+). No differences in any sleep parameters (sleep efficiency, sleep latency, total sleep time, total time in bed, wake after sleep onset, activity bathyphase) were observed between S+ and S- patients. However, S+ patients displayed a significantly worse circadian function than S- patients (96.4 vs 98.1%; p = 0.005). The presence of poor subjective sleep and objective circadian dysfunction negatively affected symptoms and QOL domains (p = 0.038). CONCLUSIONS: Subjective report of sleep problems was not associated with worse objectively measured sleep parameters in patients with MCC although it was associated with disrupted circadian rest-activity rhythm and poorer QOL. These findings coincide with prior research in cancer patients in that an inconsistent relationship exists between subjective and objective sleep measurements on some sleep domains. This study supports the value of coupled evaluation of self-reported and objective measures of sleep and circadian function in cancer patients.

Relevance of internal time and circadian robustness for cancer patients.

BACKGROUND: Adequate circadian timing of cancer treatment schedules (chronotherapy) can enhance tolerance and efficacy several-fold in experimental and clinical situations. However, the optimal timing varies according to sex, genetic background and lifestyle. Here, we compute the individual phase of the Circadian Timing System to decipher the internal timing of each patient and find the optimal treatment timing. METHODS: Twenty-four patients (11 male; 13 female), aged 36 to 77 years, with advanced or metastatic gastro-intestinal cancer were recruited. Inner wrist surface Temperature, arm Activity and Position (TAP) were recorded every 10 min for 12 days, divided into three 4-day spans before, during and after a course of a set chronotherapy schedule. Pertinent indexes, I < O and a new biomarker, DI (degree of temporal internal order maintenance), were computed for each patient and period. RESULTS: Three circadian rhythms and the TAP rhythm grew less stable and more fragmented in response to treatment. Furthermore, large inter- and intra-individual changes were found for T, A, P and TAP patterns, with phase differences of up to 12 hours among patients. A moderate perturbation of temporal internal order was observed, but the administration of fixed chronomodulated chemotherapy partially resynchronized temperature and activity rhythms by the end of the study. CONCLUSIONS: The integrated variable TAP, together with the asynchrony among rhythms revealed by the new biomarker DI, would help in the personalization of cancer chronotherapy, taking into account individual circadian phase markers.

The effect of melatonin on sleep and quality of life in patients with advanced breast cancer.

BACKGROUND: Fatigue and sleep problems are prevalent in cancer patients and can be associated with disruption of circadian rhythmicity. In this prospective phase II trial, we sought to assess the effect of melatonin on circadian biomarkers, sleep, and quality of life in breast cancer patients. METHODS: Thirty-two patients with metastatic breast cancer, receiving hormonal or trastuzumab therapy, took 5 mg of melatonin at bedtime for 2 months. Before starting and after 2 months on melatonin therapy, sleep and circadian rhythmicity were assessed by actigraphy, diurnal patterns of serum cortisol, and the expression of the core clock genes PER2 and BMAL1 in peripheral blood mononuclear cells. The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 questionnaire was completed for subjective parameters. RESULTS: Bedtime melatonin was associated with a significant improvement in a marker of objective sleep quality, sleep fragmentation and quantity, subjective sleep, fatigue severity, global quality of life, and social and cognitive functioning scales. Morning clock gene expression was increased following bedtime melatonin intake. Melatonin did not affect actigraphy measure of circadian rhythmicity, or the diurnal cortisol pattern. CONCLUSION: These results invite further investigation of melatonin as a potentially useful therapeutic agent for improving sleep and quality of life in cancer patients.

Clinical Relevance of the First Domomedicine Platform Securing Multidrug Chronotherapy Delivery in Metastatic Cancer Patients at Home: The inCASA European Project.

BACKGROUND: Telehealth solutions can improve the safety of ambulatory chemotherapy, contributing to the maintenance of patients at their home, hence improving their well-being, all the while reducing health care costs. There is, however, need for a practicable multilevel monitoring solution, encompassing relevant outputs involved in the pathophysiology of chemotherapy-induced toxicity. Domomedicine embraces the delivery of complex care and medical procedures at the patient's home based on modern technologies, and thus it offers an integrated approach for increasing the safety of cancer patients on chemotherapy. OBJECTIVE: The objective was to evaluate patient compliance and clinical relevance of a novel integrated multiparametric telemonitoring domomedicine platform in cancer patients receiving multidrug chemotherapy at home. METHODS: Self-measured body weight, self-rated symptoms using the 19-item MD Anderson Symptom Inventory (MDASI), and circadian rest-activity rhythm recording with a wrist accelerometer (actigraph) were transmitted daily by patients to a server via the Internet, using a dedicated platform installed at home. Daily body weight changes, individual MDASI scores, and relative percentage of activity in-bed versus out-of-bed (I

The circadian rest-activity rhythm, a potential safety pharmacology endpoint of cancer chemotherapy.

The robustness of the circadian timing system (CTS) was correlated to quality of life and predicted for improved survival in cancer patients. However, chemotherapy disrupted the CTS according to dose and circadian timing in mice. A continuous and repeated measures longitudinal design was implemented here to characterize CTS dynamics in patients receiving a fixed circadian-based chemotherapy protocol. The rest-activity rhythm of 49 patients with advanced cancer was monitored using a wrist actigraph for 13 days split into four consecutive spans of 3-4 days each, i.e., before, during, right after and late after a fixed chronotherapy course. The relative amount of activity in bed vs. out of bed (I

Digital Remote Monitoring Using an mHealth Solution for Survivors of Cancer: Protocol for a Pilot Observational Study.

BACKGROUND: Healthy lifestyle interventions have a positive impact on multiple disease trajectories, including cancer-related outcomes. Specifically, appropriate habitual physical activity, adequate sleep, and a regular wholesome diet are of paramount importance for the wellness and supportive care of survivors of cancer. Mobile health (mHealth) apps have the potential to support novel tailored lifestyle interventions. OBJECTIVE: This observational pilot study aims to assess the feasibility of mHealth multidimensional longitudinal monitoring in survivors of cancer. The primary objective is to test the compliance (user engagement) with the monitoring solution. Secondary objectives include recording clinically relevant subjective and objective measures collected through the digital solution. METHODS: This is a monocentric pilot study taking place in Bangor, Wales, United Kingdom. We plan to enroll up to 100 adult survivors of cancer not receiving toxic anticancer treatment, who will provide self-reported behavioral data recorded via a dedicated app and validated questionnaires and objective data automatically collected by a paired smartwatch over 16 weeks. The participants will continue with their normal routine surveillance care for their cancer. The primary end point is feasibility (eg, mHealth monitoring acceptability). Composite secondary end points include clinically relevant patient-reported outcome measures (eg, the Edmonton Symptom Assessment System score) and objective physiological measures (eg, step counts). This trial received a favorable ethical review in May 2023 (Integrated Research Application System 301068). RESULTS: This study is part of an array of pilots within a European Union funded project, entitled "GATEKEEPER," conducted at different sites across Europe and covering various chronic diseases. Study accrual is anticipated to commence in January 2024 and continue until June 2024. It is hypothesized that mHealth monitoring will be feasible in survivors of cancer; specifically, at least 50% (50/100) of the participants will engage with the app at least once a week in 8 of the 16 study weeks. CONCLUSIONS: In a population with potentially complex clinical needs, this pilot study will test the feasibility of multidimensional remote monitoring of patient-reported outcomes and physiological parameters. Satisfactory compliance with the use of the app and smartwatch, whether confirmed or infirmed through this study, will be propaedeutic to the development of innovative mHealth interventions in survivors of cancer. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/52957.