Page 55 - ARNM-3-3

Advances in Radiotherapy
& Nuclear Medicine LuPSMA response patterns on PSMA PET

Figure 2. The distributions of resolved, reducing, stable, increasing, and new lesions are shown for each participant. Most participants had a heterogenous
tumor response which included resolved, reducing, increasing, and new lesions.

TLW-defined progression. In contrast, only 11% (1/9) of Table 3. Univariable Cox regression analysis for association
TLW “responders” had PSA progression (Table 2). with OS from time of post‑treatment PSMA PET. Results
are presented as HR with 95%CI, with reference groups
All “responders” (9/9, 100%) demonstrated a reduction indicated in brackets
in PSMA TTV on whole-body quantitation. However, only
OS
27% (4/15) of “low-volume progressors” and 62% (8/13) of Univariable Cox regression analysis HR (95%CI)
“high-volume progressors” demonstrated any increase in
PSMA TTV. The remaining 16 participants had decreased TLW response pattern
PSMA TTV, despite the presence of new or “increasing” Responder 1.00 (ref)
lesions identified by TLW. Low-volume progressor 1.4 (0.4–4.5)
High-volume progressor 4.8 (1.4–15.8), p=0.01
3.3. TLW response patterns and survival outcomes
PSA progression* 4.8 (1.8–13.4)
Median OS from the date of post-treatment imaging p=0.002
was 17.7 months (95%CI, 12.7–22.8) for “responders,” Radiographic progression* 6.7 (2.2–20)
12.0 months (95%CI, 9.1–14.9) for “low-volume p≤0.001
progressors,” and 7.5 months (95%CI, 3.0–12.0) for “high- Note: * Indicates at time of post-treatment imaging.
volume progressors.” “Responders” demonstrated longer Abbreviations: CI: Confidence intervals; HR: Hazard ratio; OS: Overall
OS than “low-volume progressors” (hazard ratio [HR], 1.4; survival; PSA: Prostate-specific antigen; PSMA PET: Prostate-specific
95%CI, 0.4–4.6) and “high-volume progressors” (HR, 4.8; membrane antigen-positron emission tomography; ref: Reference group.
95%CI, 1.4–15.8; overall p=0.005) (Table 3 and Figure 3).
Multistate modeling supported this, showing that the (95%CI, 12.7–22.8), compared with 14.0 months (95%CI,
hazard for death was consistently lower in “responders” 10.3–17.7) for RECIP-SD, and 3.3 months (95%CI, 1.3–5.2)
than in “low-volume progressors” or in “high-volume for RECIP-PD. RECIP-PR was associated with improved
progressors” from the time of study entry (Figure A1). survival compared with RECIP-SD (HR, 1.5; 95%CI, 0.5–
PSA progression and radiographic progression at the 4.8) and RECIP-PD (HR, 15; 95%CI, 3.4–67; p<0.001). The
time of post-treatment imaging were also associated with C-index was similar for TLW and RECIP 1.0, at 0.70 and
poorer survival (HR, 6.2; 95%CI, 2.2–17.0; p =0.002) and 0.75, respectively.
(HR, 6.6; 95%CI, 2.2–20; p<0.001), respectively.
3.5. Patterns of progression
3.4. Comparison with RECIP 1.0 response The differences in PSMA intensity for TLW “responders”

The RECIP 1.0 response assessment criteria were and “progressors” were compared. TLW “progressors”
applied to this cohort. A total of 24% (9/37) had demonstrated a persistently high PSMA SUV (median
max
a RECIP partial response (RECIP-PR), 51% (19/37) had 16, range 6–73) compared with pre-treatment SUV max
RECIP stable disease (RECIP-SD), and 24% (9/37) had (median 20.4, range 5.6–122). The SUV mean remained
RECIP progressive disease (RECIP-PD). Participants relatively stable (median 4.8, range 4–10) compared with
with a RECIP-PR had a median survival of 17.7 months pre-treatment SUV mean (median 6.6, range 3.7–22.6).

Volume 3 Issue 3 (2025) 47 doi: 10.36922/ARNM025110011