Therapeutic potential of [177Lu]Lu-DOTAGA-FAPi dimers in metastatic breast cancer patients with limited treatment options: efficacy and safety assessment.

PURPOSE: The upregulation of fibroblast activation protein (FAP) expression has been observed in various cancers, including metastatic breast carcinoma, prompting research into small molecule inhibitors for both diagnostic and therapeutic purposes. While the diagnostic value of PET/CT imaging using 68 Ga- or 18F-labelled FAPi-monomers in breast cancer diagnosis is well-established, there is a significant need for therapeutic analogs. This retrospective study aimed to assess the safety and effectiveness of [177Lu]Lu-DOTAGA.FAPi dimer radionuclide therapy in patients with advanced-stage breast cancer who had previously undergone [68 Ga]Ga-DOTA.SA.FAPi PET/CT scans to confirm the expression of FAP. MATERIALS AND METHODS: Between November 2020 and March 2023, a compassionate treatment approach was utilized to administer [177Lu]Lu-DOTAGA.FAPi dimer radionuclide therapy to heavily pretreated patients with advanced breast cancer. Nineteen patients (18 females, 1 male) with metastatic breast cancer participated in the study, with an average age of 44.6 ± 10.7 years. The therapy was administered at intervals of 8 to 12 weeks, and the median follow-up duration was 14 months. The primary objective of the study was to assess molecular response using [68 Ga]Ga-DOTA.SA.FAPi PET/CT scans, with response evaluation based on the PERCIST criteria. Secondary endpoints included overall survival (OS), progression-free survival (PFS), clinical response assessment, and safety evaluation using CTCAE v5.0 guidelines. RESULTS: A total of 65 cycles were administered, with a mean cumulative activity of 19 ± 5.7 GBq (510 ± 154 mCi) ranging from 11 to 33.3 GBq (300 to 900 mCi) of [177Lu]Lu-DOTAGA.FAPi dimer. The number of cycles ranged from 2 to 6, with a median of 3 cycles. The treatment protocol consisted of different numbers of cycles administered to the patients: specifically, two cycles were given to five patients, three cycles to nine patients, four cycles to one patient, and six cycles to four patients. Most patients had invasive/infiltrative ductal carcinoma (94.7%), while a small percentage had invasive lobular carcinoma (5.3%). All patients had bone metastases, and five of them also had liver involvement, while seven had brain metastases. Response assessment using [68 Ga]Ga-DOTA.SA.FAPi PET/CT scans showed that 25% of the 16 patients evaluated had partial remission, while 37.5% exhibited disease progression. According to the VAS response criteria, 26.3% achieved complete response, 15.7% had partial response, 42% showed minimal response, 11% had stable disease, and 5% had no response. The clinical disease control rate was promising, with 95% of patients achieving disease control. The clinical objective response rate was 84%. The median follow-up period was 14 months. At the time of analysis, the median overall survival was 12 months, and the median progression-free survival was 8.5 months. Notably, no severe hematological, renal, or hepatic toxicities, electrolyte imbalances, or adverse events of grade 3 or 4 were observed during the study. CONCLUSION: The findings suggest that [177Lu]Lu-DOTAGA.FAPi dimer therapy is well-tolerated, safe, and effective for treating end-stage metastatic breast cancer patients. [177Lu]Lu-DOTAGA.FAPi dimer treatment demonstrated promising efficacy in patients with advanced breast cancer, as indicated by high disease control rates, favorable response outcomes, and acceptable safety profile. Further research and longer follow-up are warranted to assess long-term outcomes and validate these findings.

Relevance of polyclonal plasma cells and post-therapy immunomodulation in measurable residual disease assessment in multiple myeloma.

BACKGROUND: Immunophenotypic profile and post-therapy alteration in antigenic expression were evaluated in normal, reactive, and aberrant plasma cells (NPC, RPC, and APC) for impact on measurable residual disease (MRD) assessment in multiple myeloma (MM). METHODS: Samples from non-MM staging marrow (n = 30), Hodgkin's lymphoma (n = 30) and MM (n = 724) were prospectively evaluated for expression profiles of NPC, RPC, and APC using antigens recommended in consensus guidelines. RESULTS: Polyclonal NPC-RPC demonstrated aberrations for all antigens evaluated with a higher frequency of aberrancies in post-therapy samples compared to treatment naïve samples (p < 0.001%). Immunomodulation in APC was observed in 79% of post-therapy samples with a change in expression of 1, 2, and ≥3 antigens in 19.9%, 15.6%, and 43.5% samples, respectively. In 13.4% of samples, APC showed no aberrancy and aberrant status was assigned based on cytoplasmic light chain restriction (cyLCR) alone. 9% samples with an admixture of NPC and APC displayed normal cytoplasmic kappa to lambda ratio (cyKLR) when the percentage of APC of total PC (neoplastic plasma cell index, NPCI), was below 25% and 50% for kappa and lambda restricted cases, respectively. CONCLUSION: The panorama and high frequency of antigenic aberrations on polyclonal PC signify the importance of MRD assay validation on a large cohort under normal and reactive conditions. Frequent Immunophenotypic shifts in APC re-confirm the redundancy of baseline immunophenotype for MRD evaluation. Small clones of APC may be missed by assessment of cyKLR alone and therefore, surface marker aberrancy supported by cyLCR is required for definitive assignment of residual APC.

Critical evaluation of the utility of pre- and post-therapy immunophenotypes in assessment of measurable residual disease in B-ALL.

Measurable residual disease (MRD) is an important parameter to predict outcome in B-cell acute lymphoblastic leukemia (B-ALL). Two different approaches have been used for the assessment of MRD by multiparametric flow cytometry that include the "Leukemia Associated Aberrant Immunophenotype (LAIP)" and "Difference from Normal (DFN)" approach. In this retrospective study, we analyzed 539 samples obtained from 281 patients of which 258 were paired samples and the remaining 23 samples were from post-induction time point only, to explore the utility of baseline immunophenotype (IPT) for MRD assessment. Single-tube 10-color panel was used both at diagnosis and MRD time points. Out of 281 patients, 31.67% (n = 89) were positive and 68.32% (n = 192) were negative for MRD. Among 258 paired diagnostic and follow-up samples, baseline IPT was required in only 9.31% (24/258) cases which included cases with hematogone pattern and isolated dim to negative CD10 expression patterns. Comparison of baseline IPT with post-induction MRD positive samples showed a change in expression of at least one antigen in 94.04% cases. Although the immunophenotypic change in expression of various antigens is frequent in post-induction samples of B-ALL, it does not adversely impact the MRD assessment. In conclusion, the baseline IPT is required in less than 10% of B-ALL, specifically those with hematogone pattern and/or dim to negative expression of CD10. Hence, a combination of DFN and LAIP approach is recommended for reliable MRD assessment.

Comparative assessment of prognostic models in chronic lymphocytic leukemia: evaluation in Indian cohort.

Prognostic indices combining several clinical and laboratory parameters have been proposed for prognostication in chronic lymphocytic leukemia (CLL). Recently, international consortium on CLL proposed an international prognostic index (CLL-IPI) integrating clinical, molecular, and genetic parameters. The present study was designed to evaluate the reproducibility of CLL-IPI in Indian CLL cohort. The prognostic ability of CLL-IPI in terms of overall survival (OS) and time to first treatment (TTFT) was investigated in treatment-naive CLL patients and also compared with other existing prognostic scores. For assigning scores, clinical and laboratory details were obtained from medical records, and IGHV gene mutation status, ß2-microglobulin levels, and copy number variations were determined using c-DNA, ELISA, and multiplex ligation-dependent probe amplification (MLPA), respectively. The scores were generated as per the weighted grades assigned to each variable involved in score categorization. The predictive value of prognostic models was assessed and compared using Harrell's C-index and Akaike's information criterion (AIC). Stratification of patients according to CLL-IPI yielded significant differences in terms of OS and TTFT (p < 0.001). Comparative assessment of scores for OS suggested better performance of CLL-IPI (C = 0.64, AIC = 740) followed by Barcelona-Brno (C = 0.61, AIC = 754) and MDACC score (C = 0.59, AIC = 759). Comparison of predictive value of prognostic scores for TTFT illustrated better performance of CLL-IPI (C = 0.72, AIC = 726) followed by Barcelona-Brno (C = 0.68, AIC = 743), modified GCLLSG (C = 0.66, AIC = 744), and O-CLL1 index (C = 0.55, AIC = 773). The results suggest better performance of CLL-IPI in terms of both OS and TTFT as compared to other available scores in our cohort.

Assessment of 285 cases of chronic lymphocytic leukemia seen at single large tertiary center in Northern India.

Chronic lymphocytic leukemia (CLL) is the most common lymphoproliferative disorder in the West accounting for about 30% of leukemias, but about 2-4% in India. There is no large series reported from India, and hence we decided to undertake this study. We assessed the clinicohematological profiles and treatment outcomes in 285 patients seen over 11 years at our center (median age 59 years, 209 males). Sixty-three patients (22%) were asymptomatic and diagnosed incidentally. The median total leukocyte count at presentation was 50 × 10(9)/L. Rai stage distribution was: stage 0, 10%; stage I, 16%; stage II, 33%; stage III, 20%; and stage IV, 21%. Fifty percent of patients required treatment at presentation. Ninety-six patients received chlorambucil-based (overall response rate [ORR] 69%, complete remission [CR] 3%) and 27 patients received fludarabine-based (ORR 89%, CR 44%) chemotherapy. With a median follow-up of 2.9 years, the median overall survival (OS) and event-free survival (EFS) were 5.1 and 4.6 years, respectively. Fludarabine was more toxic, as half of the patients developed febrile neutropenia and various infections. The majority of patients presented with advanced stage disease. Fludarabine was less commonly used as first-line therapy. Advanced clinical stage (Rai III and IV) was associated with poor OS (hazard ratio [HR] 2.46, 95% confidence interval [CI] 1.19-5.11, p = 0.001) and EFS.