Prognostic Value of FDG-PET/CT Parameters in Patients with Relapse/Refractory Multiple Myeloma before Anti-CD38 Based Therapy

• Main Authors: Guillemette Fouquet, Myriam Wartski, Amina Dechmi, Lise Willems, Bénédicte Deau-Fischer, Patricia Franchi, Justine Descroocq, Paul Deschamps, Estelle Blanc-Autran, Jérôme Clerc, Didier Bouscary, Sylvain Barreau, Nicolas Chapuis, Marguerite Vignon, Anne-Ségolène Cottereau
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Cancers
• Subjects: myeloma; immunotherapy; anti-CD38; FDG-PET/CT; prognostic factor; focal bone lesion
• Online Access: https://www.mdpi.com/2072-6694/13/17/4323

Although anti-CD38 monoclonal antibodies have improved the prognosis of relapsed/refractory multiple myeloma (RRMM), some patients still experience early relapses with poor outcomes. This present study evaluated the predictive value of FDG PET/CT parameters for RRMM prior to initiating anti-CD38 treatment. We included 38 consecutive RRMM patients who underwent a PET/CT scan treated at our institution at relapse. The median PFS was 12.5 months and the median OS was not reached. 42% of the patients had an initial ISS score of 1, 37% of 2, and 21% of 3. The presence of >3 focal lesions (FLs, <i>n</i> = 19) and the ISS score were associated with inferior PFS (<i>p</i> = 0.0036 and <i>p</i> = 0.0026) and OS (<i>p</i> = 0.025 and <i>p</i> = 0.0098). Patients with >3 FLs had a higher initial ISS score (<i>p</i> = 0.028). In multivariable analysis, the ISS score and >3 FLs were independent prognostic factors for PFS (<i>p</i> = 0.010 and <i>p</i> = 0.025 respectively), and combined they individualized a high-risk group with a median PFS and OS of 3.1 months and 8.5 months respectively vs. not reached for the other patients. The presence of >3 FLs on PET was predictive of survival outcomes in patients with RRMM treated using CD38 targeted therapy. Combined with the initial ISS, an ultra-high-risk RRMM population can thus be identified.