JOURNAL ONKOLOGIE – STUDIE

Head-to-head Comparison of 68Ga-PSMA-11 and 18F-PSMA-1007

Studien-Informationen Einschlusskriterien Studien-Rationale Studien-Arme Geprüfte Regime

Rekrutierend

NCT-Nummer:
NCT05079828

Studienbeginn:
Juli 2022

Letztes Update:
25.04.2023

Wirkstoff:
-

Indikation (Clinical Trials):
Prostatic Neoplasms

Geschlecht:
Männer

Altersgruppe:
Erwachsene (18+)

Phase:
-

Sponsor:
University Hospital Inselspital, Berne

Collaborator:
-

Studienleiter

Axel Rominger, MD
Study Chair
Inselspital

Kontakt

Céline Birrer
Kontakt:
Phone: +41 31 632 24 54
E-Mail: celine.birrer@insel.ch» Kontaktdaten anzeigen

Ali Afshar-Oromieh, MD
Kontakt:
Phone: +41 31 632 24 54
E-Mail: ali.afshar@insel.ch» Kontaktdaten anzeigen

Studienlocations
(1 von 1)

Inselspital, Universitätsspital Bern
3010 Bern
SwitzerlandRekrutierend» Google-Maps

Studien-Informationen

Detailed Description:

Prostate Cancer (PC) is the most common malignancy in men and the second leading cause of

cancer-related death in men. Despite initial therapy at early stage disease, biochemical

recurrence remains a commonly encountered entity and presents a challenge for conventional

imaging modalities given their limited abilities to detect disease at early stages of

recurrence.

PET/CT with ligands of the prostate specific membrane antigen has been shown to have a

significant impact on treatment and is now the sine qua non for staging of recurrent PC. For

example, accurate identification of PC lesions allows for more accurate radiotherapy

planning, allowing for an individualised treatment strategy. There is therefore a substantial

clinical requirement for the accurate identification and stratification of individuals in

whom prostate cancer is diagnosed and at earlier stages of recurrent disease when the chance

of a curative treatment is at its highest.

It is in this context that PSMA has become the focus of much attention owing to its high

levels of expression on PC cells and has rapidly established itself as the investigation of

choice in recurrent PC. Furthermore, PSMA-directed radioligand therapy is a rapidly evolving

treatment modality for metastatic disease, creating an additional therapeutic role for

PSMA-ligand molecular imaging, for which the term "theragnostics" has been coined. The

challenge for nuclear medicine is therefore to develop tracers and examination protocols that

provide optimal detection and characterisation of disease, thus improving upon this promising

technique.

There are currently no published prospective head-to-head studies comparing these two tracers

in recurrent PC. Because of this lack of data, there are no clear recommendations about which

tracer to use and in which situation.

This study aims to fill this gap and provide comprehensive data with the potential to improve

the diagnosis of PC. By providing robust data comparing the two tracers, such data will also

provide guidance to clinicians faced with the scenario of an initially negative 68Ga-PSMA-11

PET as to the diagnostic utility of an additional 18F-PSMA-1007 PET, or vice-versa, and in

which scenarios repeated scanning may be justified.

Finally, the application of the radiotracer into the same patient allows for a comparison of

tracer kinetics. Although radiotracer kinetics are well known from the original pioneering

dosimetric publications, they have never been compared in a head to head fashion and not in

biochemical recurrence. Obtaining dynamic scans over the first hour post injection will allow

intra-individual dosimetry and a head-to-head comparison of parametric imaging parameters,

allowing a direct comparison of the radiotracer's affinity using standard parametric imaging

techniques.

Ein-/Ausschlusskriterien

Inclusion Criteria:

- Patients with known biochemical recurrence of a histologically confirmed prostate

cancer post radical prostatectomy, defined as two consecutive prostate specific

antigen (PSA) values > 0.2 ng/ml:

- Post prostatectomy: Patients > 18 y/o

- PSA measured within ± 4 weeks of the first PSMA-PET/CT

- Patients providing written informed consent

- No change in PC treatment in the period between the first and second scans

Exclusion Criteria:

- Patients receiving androgen deprivation therapy (ADT) within 6 months prior to the

PSMA-PET/CT

- Patients with contraindication to diuresis with 20mg Furosemide

- Patients with renal dialysis or relevant renal impairment (eGFR < 35 ml/min)

- Inability to provide written informed consent

- Inability to schedule and attend two consecutive PET examinations

- Patients undergoing active treatment for a second non-prostatic malignancy at the time

of the first scan.

- Known sensitivity or allergy to PSMA-ligands or one of the components of the

radiotracer solutions used.

Studien-Rationale

Primary outcome:

1. Patient-level detection rate (Time Frame - 3-6 months following final scan):
The primary endpoint is the proportion of patients with a pathological PSMA-positive finding (= patient-based sensitivity) at one time-point (2h) with the existing standard-of-care (68Ga-PSMA-11) compared to the new tracer (18F-PSMA-1007).

Secondary outcome:

1. Comparison of tracer kinetics (Time Frame - For the first n=10 individuals, expected to be after 3 months):
Intra-individual comparison of the parametric imaging parameter KD (measure of tracer affinity) for the two radiotracers.

2. Per region-based detection rate (Time Frame - Confirmed by 12 months' follow up from date of scan to a composite standard):
- The number of pathological, benign and uncertain lesions for each tracer in five regions (prostate bed, pelvic lymph nodes, extra-pelvic lymph nodes, bone, or other organs) classified by six blinded readers (three for each tracer) using previously published interpretation guidelines (PSMA-Rads 1.0)

3. Interreader reliability (Time Frame - Within 3-6 months of last scan):
Readers shall independently classify all PSMA-avid lesions according to previously published diagnostic criteria. The frequency of benign, equivocal and pathological lesions will be noted. Lesions will additionally be classified by region (prostate bed (T), pelvic lymph nodes (N), extrapelvic lymph nodes (M1a), bone (M1b) or other organs (M1c)). The interreader reliability for these classifications will be compared between all readers.

4. Region based PPV (Time Frame - 12 months from the last scan):
- The positive predictive value (PPV) stratified by region (local recurrence, lymph node, solid organ, bone) i.e. the percentage of pathological lesions that are confirmed pathological at the twelve months follow-up (based on the subset of patients and lesions with follow-up data at twelve months).

5. Lesion semiquantitative radiotracer uptake (Time Frame - Within 6 months of scan date):
- semiquantitative radiotracer uptake will be assessed by standardised uptake values (SUV) as well as tumour to background contrast in a lesion based analysis. The tumour to background ratio (TBR) is defined as lesion SUV ÷ SUV of reference background region, where the background uptake is defined by convention as the left gluteal musculature

6. Number of patients with adverse events and their severity (Time Frame - 48 hours):
- Number and severity of adverse events per tracer (up to 48 hours follow up).

7. Lesion based PPV (Time Frame - 12 months from the last scan):
In a second round of tumour classification, two readers (in consensus) will classify each lesion as pathological, benign or uncertain in a lesion-specific approach and perform a lesion based follow-up to assess PPV on the lesion level.

Studien-Arme

Active Comparator: Arm 1
Patients receive first a PET/CT with 68Ga-PSMA-11 and a second PET/CT with 18F-PSMA-1007
Active Comparator: Arm 2
Patients receive first a PET/CT with 18F-PSMA-1007 and a second with 68Ga-PSMA-11

Geprüfte Regime

18F-PSMA-1007:
PET/CT scan using 18F-PSMA-1007
68Ga-PSMA-11:
PET/CT scan using 68Ga-PSMA-11

Quelle: ClinicalTrials.gov

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