Abstract Introduction Treatment retention is crucial for patients with chronic diseases, impacting both clinical outcomes and healthcare costs. Patient Support Programs (PSP), often sponsored by pharmaceutical companies as a wraparound support service for new and innovative medicines, have been shown to be a viable tool in supporting treatment retention and adherence1. Utilizing tools like Patient Activation Measure (PAM®) equips healthcare providers with a means to evaluate the impact of these PSPs on patients' activation and their potential to adhere to medication. The PAM is a behavioural concept focusing on a patient’s understanding of their role in their healthcare, and how competent they feel to fulfil that role. Crucially, there is substantial evidence indicating a strong association between higher PAM scores and improved clinical outcomes2. Aim This study objectives are to evaluate the effectiveness of PSP in reducing treatment drop-off; to investigate the impact of PSP on patient activation/PAM levels; and to analyse potential cost savings from patient activation through PSP participation. Methods The study population includes patients (n= 97795) diagnosed with chronic diseases receiving one of three services from a Clinical Homecare company: (1) Direct-to-patient medication delivery (DD); (2) DD plus self-administration training and (3) DD, self-administration training and PAM-based PSP. Patient “drop-off” from treatment was analysed across all three services and defined as discontinuation of medication due to unwillingness to engage, non-response to engagement attempts, or requests to put the service on hold. Additionally, change in PAM level/activation for patients who completed baseline and follow-up PAM surveys between October 2020 and March 2024 (n=1880) was considered. Finally, expected cost saving was examined, both as a result of the observed change in activation for PSP patients as well as in a hypothetical scenario where patients in DD and self-administration training are redirected to PSP. Ethical approval was not required because the study does not involve any patient interaction/intervention whatsoever. It was a retrospective data analytical study, using existing and fully anonymised patient data from routine clinical care. Results Fewer patients drop off from treatment when they are on the PSP (1.1%) compared to those that are on self-administration training (2.1%) or DD (2.8%). Participation in PSP also positively impacted PAM scores across all therapies, with average improvements ranging from 1 to 8.1 points per patient. Patients in the lower two activation levels (typically at the greatest risk of non-adherence) experienced the most substantial gains (ranging from 8.4 to 17.4 points) emphasizing the significance of intervention. These improvements in PAM scores by PSP translated to substantial cost savings for the health system, amounting to £1,028,669. Finally, where the same treatment drop-off rate and PAM performance ratio are applied to a hypothetical scenario involving the redirection of patients from DD and self-administration training to PSP, there is a further potential cost savings of £4,298,277. Conclusion Participation in PSP improves patient activation and the potential to adhere to prescribed medication, while producing significant financial benefits. Further research is needed to understand how these benefits may vary across different therapy areas and within primary, secondary, and homecare settings.