(P 149) CHARACTERISTICS OF PATIENTS WITH BONE AND SOFT TISSUE SARCOMAS REFERRED TO A DEDICATED EARLY PHASE CLINICAL TRIAL CLINIC

Objective: Advanced bone and soft tissue sarcomas have limited effective systemic treatment options. With the evolution of molecularly targeted agents and immunotherapeutics, early phase clinical trials (ECT) play an important role in expanding the therapeutic options available to patients with these tumours. Our institution implemented a dedicated clinic to streamline recruitment and coordinate a central waiting list for ECTs. This has increased overall recruitment to clinical trials compared to the 12 months prior to implementation across all tumour types.(1) As a state-sarcoma service, bone and soft tissue tumours contribute 17% of referrals to our ECT clinic.(1) The objective of this study was to evaluate the characteristics of patients with bone and soft tissue tumours referred to this ECT clinic.

(1) Chye A, Strach M, Horvath L, Hui M. A Retrospective Study of Early-Phase Oncology Clinical Trial Patients After Implementation of a Dedicated Phase 1 Clinic in an Australian Cancer Centre. Asia Pac J Clin Oncol. 2020;16(S2):29–47.

Methods: We collected demographics, clinicopathological variables, treatment characteristics and follow-up status from patients with advanced bone and soft tissue sarcomas referred to our institution’s dedicated ECT clinic from inception in July 2019 to June 2022. Primary outcomes included proportion of patients recruited to a clinical trial, and for those recruited, the time from referral to the clinic to commencement of the investigational product. Secondary outcomes included overall survival (OS) calculated from dates of diagnosis and ECT referral. Data was analysed using Kaplan Meier and Cox regression methods.

Results: 74 patients with histologically confirmed bone and soft tissue sarcomas were referred for consideration of ECTs. Median follow-up, calculated from the time of ECT referral, was 15.7 months (0.3-37.0). Mean age at diagnosis was 52 (range 20-80) years and median age at ECT referral was 54 (21-83) years. Baseline characteristics are summarised in Table 1. 57% of this cohort were male. 16 (22%) had primary bone sarcomas, 27 (36%) had primary L-sarcoma and 31 (42%) primary soft tissue sarcomas. 35 (49%) of patients referred were recruited to an ECT at our institution and 6 (8%) to an ECT at an external institution. The majority of patients recruited to an ECT received an immunotherapeutic agent (83%), followed by combination immunotherapy and targeted therapy (28%). 20/36 (56%) of patients who received an ECT had a matched therapy. The median time from referral to ECT to receipt of investigational product was 12.5 months (95% CI 7.3-17.7; Figure 1). 35% of patients received ECT treatment by 3 months and 42% by 6 months. Survival outcomes are summarised in Table 2. Median OS from time of referral to clinic was longer for patients recruited to an ECT (23 months) compared to those who were not (10 months), HR 2.8, 95% CI 1.4-5.5, p=0.002 (Figure 2).

Conclusion: This study demonstrates the benefits of engaging patients with bone and soft tissue sarcomas in an ECT clinic, with over half receiving a matched active agent at our or external institution, and the potential for improved survival. It is feasible to consider older patients for referral to ECTs as 23 (31%) were aged above 65. Although 49% of patients referred were successfully recruited to an ECT, a delay was observed to time of commencement on trial. This is contributed by the small number of slots available for dose finding studies and number of trials actively recruiting at time of referral. Hence, it is important to counsel patients regarding expectations of potential ECTs and emphasises the importance of early referral for ECTs and processes to reduce time to trial entry for patients with these sarcomas. The OS benefit seen could have been influenced by selection bias of fitter, younger, motivated patients without rapid progression who are more likely to be enrolled into clinical trials. We plan further study of patient and clinician factors involved in ECT referral.

CTOS_P1Sarc_Table1.pdf

CTOS_P1Sarc_Table2.pdf

CTOS_P1Sarc_Figure1.pdf

CTOS_P1Sarc_Figure2.pdf