89Zr-olaratumab Dosimetry in Participants With Soft Tissue Sarcoma

INCLUSION CRITERIA:

1. ≥18 years of age at the time of signing the informed consent.

2. Histologically confirmed diagnosis of soft tissue sarcoma (STS)

3. At least one mass of > 2 cm in largest diameter seen on standard of care imaging (CT, MRI and/or FDG-PET).

4. For Part A: Participants must have tumour PDGFRα expression confirmed by IHC.Participants must have consented to provide archived FFPE tumour tissue or besubject to a biopsy of the target tumour (if archived tissue is unavailable). For Parts B and C: all participants will be included regardless of their PDGFRαexpression status on archival tissue/biopsy (unless otherwise specified).Participants must have consented to provide available archived FFPE tumour tissue.

5. Adequate haematologic function as defined by an absolute neutrophil count (ANC) ≥ 1500/ μL, haemoglobin ≥ 9.0 g/dL, and a platelet count of 100,000/μL obtained.

6. Adequate hepatic function as defined by a total bilirubin ≤ 1.5 mg/dL, and aspartatetransaminase (AST) and alanine transaminase (ALT) ≤ 3.0 times the upper limit ofnormal (ULN).

7. Adequate renal function as defined by serum creatinine ≤ 1.5 × the institutionalULN. If creatinine is above the ULN, the participant's creatinine clearance is ≥ 45mL/min.

8. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.

9. Life expectancy of at least 6 months.

10. Female participants of childbearing potential must have negative pregnancy tests atscreening, as well as confirmation of negative pregnancy test result within 24 hoursprior to receiving 89Zr-TLX300-CDx. Female participants of childbearing potential ormale participants with female partners of childbearing potential must:

11. be willing to practice full and true sexual abstinence; or

12. be surgically/permanently sterile or with a history of hysterectomy for women;or

13. be willing to practice highly effective contraception by using: a non-oral,injected or implanted non-oestrogen progesterone based hormonal method, malecondom, vaginal diaphragm, cervical cap, intrauterine device, for 3 monthsafter the administration of 89Zr-TLX300-CDx.

14. Capable of giving signed informed consent which includes compliance with therequirements and restrictions listed in the informed consent form (ICF) and in thisprotocol.

EXCLUSION CRITERIA:

1. Known or suspected hypersensitivity to olaratumab, DFOsq, 89Zr or any of theexcipients.

2. IgE antibodies against galactose-α-1,3-galactose (α-Gal) above the upper limit ofnormal, > 0.7 kU/L.

3. Exposure to any experimental diagnostic or therapeutic drug within 30 days from thedate of planned administration of 89Zr-TLX300-CDx.

4. Surgery ≤ 2 weeks prior to the administration of 89Zr-TLX300-CDx or significantongoing complications of surgery. Biopsy ≤ 2 weeks prior to the administration of 89Zr-TLX300-CDx is allowed.

5. Exposure to any radiopharmaceutical within 10 half-lives prior to the administrationof 89Zr-TLX300-CDx.

6. Ongoing toxicity Grade 2 or higher from previous standard or investigationaltherapies (Common Terminology Criteria for Adverse Events [CTCAE] version 5).

7. Planned to commence systemic antineoplastic therapies, immunotherapy, targetedtherapy, radiotherapy and/or surgery for the period between administration of 89Zr-TLX300-CDx and last imaging timepoint.

8. Serious non-malignant disease (e.g., psychiatric, infectious, autoimmune ormetabolic) or any disease that may interfere with the objectives of the study orwith the safety or compliance of the participant, as judged by the Investigator.

9. Pregnant or lactating women.

10. Participants unable to declare meaningful informed consent on their own (e.g., withlegal guardian for mental disorders) or unable to tolerate the study procedures.