Prospective monitoring of chronic myeloid leukemia patients from the time of TKI discontinuation: the fate of peripheral blood CD26+ leukemia stem cells.

Introduction: In chronic myeloid leukemia (CML), about half of the patients achieving a deep and stable molecular response with tyrosine kinase inhibitors (TKIs) may discontinue TKI treatment without disease recurrence. As such, treatment-free remission (TFR) has become an ambitious goal of treatment. Given the evidence that deepness and duration of molecular response are necessary but not sufficient requisites for a successful TFR, additional biological criteria are needed to identify CML patients suitable for efficacious discontinuation. Leukemia stem cells (LSCs) are supposed to be the reservoir of the disease. Previously, we demonstrated that residual circulating CD34+/CD38-/CD26+ LSCs were still detectable in a consistent number of CML patients during TFR. Methods: CML LSCs could be easily identified by flow-cytometry as they express the CD34+/CD38-/CD26+ phenotype. In this study, we explored the role of these cells and their correlation with molecular response in a cohort of 109 consecutive chronic phase CML patients prospectively monitored from the time of TKI discontinuation. Results: After a median observation time of 33 months from TKI discontinuation, 38/109 (35%) patients failed TFR after a median time of 4 months, while 71/109 (65%) patients are still in TFR. At TKI discontinuation, peripheral blood CD26+LSCs were undetectable in 48/109 (44%) patients and detectable in 61/109 (56%). No statistically significant correlation between detectable/undetectable CD26+LSCs and the rate of TFR loss was found (p = 0.616). The incidence of TFR loss based on the type of TKI treatment was statistically significant for imatinib treatment compared to that of nilotinib (p = 0.039). Exploring the behavior of CD26+LSCs during TFR, we observed fluctuating values that were very variable between patients, and they were not predictive of TFR loss. Discussion: Up to date, our results confirm that CD26+LSCs are detectable at the time of TKI discontinuation and during TFR. Moreover, at least for the observation median time of the study, the persistence of "fluctuating" values of residual CD26+LSCs does not hamper the possibility to maintain a stable TFR. On the contrary, even patients discontinuing TKI with undetectable CD26+LSCs could undergo TFR loss. Our results suggest that factors other than residual LSCs "burden" playing an active role in controlling disease recurrence. Additional studies evaluating CD26+LSCs' ability to modulate the immune system and their interaction in CML patients with very long stable TFR are ongoing.

"Friends and foes" of multiple myeloma measurable/minimal residual disease evaluation by next generation flow.

Next Generation Flow (NGF) represents a gold standard for the evaluation of Minimal Residual Disease (MRD) in Multiple Myeloma (MM) patients at any stage of treatment. Although the assessment of MRD is still not universally employed in clinical practice, numerous studies have demonstrated the strength of MRD as a reliable predictor of long-term outcome, and its potential to supersede the prognostic value of CR. The possibility to acquire millions of events, in combination with the use of standard reagents and a good expertise in the analysis of rare populations, led to high chance of success and a sensitivity of 10-6 that is superimposable to the one of Next Generation Sequencing molecular techniques. Some minor bias, correlated to the protocols applied, to the quality of samples and to the high heterogeneity of plasma cells phenotype, may be overcome using standard protocols and having at disposition personnel expertise for MRD analysis. With the use of NGF we can today enter a new phase of the quantification of residual disease, switching from the definition of "minimal" residual disease to "measurable" residual disease. This review takes account of the principle "friends and foes" of Myeloma "Measurable" Residual Disease evaluation by NGF, to give insights into the potentiality of this technique. The optimization of the quality of BM samples and the analytic expertise that permits to discriminate properly the rare pathologic clones, are the keys for obtaining results with a high clinical value that could be of great impact and relevance in the future.

Long-term CR Multiple Myeloma Patients Show Cured or MGUS-like Minimal Residual Disease Pattern by Next Generation Flow.

BACKGROUND: In the era of novel agents, many multiple myeloma patients can achieve a complete remission, but most of them relapse, and minimal residual disease detection can play a crucial role. Next-generation flow (NGF) can detect monoclonal plasma cells with a sensitivity of 10-6. Little is known about long-term remission patients (> 2 years) and in particular, if more sensitive techniques such as NGF can still detect minimal disease in those patients. OBJECTIVE: Aim of the study was to analyze patients with MM in response to NGF at > 2 years of sustained remission after several treatments. METHODS: MRD was studied by NGF in bone marrow aspirates according to Euroflow Consortium indications. RESULTS: 62 patients with sustained CR at >2 years were studied, MRD+ status was detected at a threshold cut-off of 10-6 in 32/62 (52%); 4/15 (27%) patients were MRD positive at >5 years of remission and they displayed a prevalence of normal vs abnormal monoclonal plasma cell immune-phenotype (MGUS-like). CONCLUSION: NGF is a powerful technique to detect MRD. Myeloma patients in prolonged sustained complete remission can show in high percentage an MRD negative status or MGUS like.

Gemcitabine, oxaliplatin, levofolinate, 5-fluorouracil, granulocyte-macrophage colony-stimulating factor, and interleukin-2 (GOLFIG) versus FOLFOX chemotherapy in metastatic colorectal cancer patients: the GOLFIG-2 multicentric open-label randomized phase III trial.

The GOLFIG-2 phase III trial was designed to compare the immunobiological activity and antitumor efficacy of GOLFIG chemoimmunotherapy regimen with standard FOLFOX-4 chemotherapy in frontline treatment of metastatic colorectal cancer (mCRC) patients. This trial was conceived on the basis of previous evidence of antitumor and immunomodulating activity of the GOLFIG regimen in mCRC. GOLFIG-2 is a multicentric open/label phase III trial (EUDRACT: 2005-003458-81). Chemo-naive mCRC patients were randomized in a 1:1 ratio to receive biweekly standard FOLFOX-4 or GOLFIG [gemcitabine (1000 mg/m(2), day 1); oxaliplatin (85 mg/m(2), day 2); levofolinate (100 mg/m(2), days 1-2), 5-fluorouracil (5-FU) (400 mg/m(2) in bolus followed by 24 h infusion at 800 mg/m(2),days 1-2), sc. GM-CSF (100 µg, days 3-7); sc. aldesleukin (0·5 MIU bi-daily, days 8-14 and 17-30)] treatments. The study underwent early termination because of poor recruitment in the control arm. After a median follow-up of 43.83 months, GOLFIG regimen showed superiority over FOLFOX in terms of progression-free survival [median 9·23 (95% confidence interval (CI), 6·9-11.5) vs. median 5.70 (95% CI, 3.38-8.02) months; hazard ratio (HR): 0.52 (95% CI, 0.35-0.77), P=0·002] and response rate [66.1% (95% CI, 0.41-0.73) vs. 37·0% (95% CI, 0.28-0.59), P=0.002], with a trend to longer survival [median 21.63 (95% CI, 18.09-25.18) vs. 14.57 mo (95% CI, 9.07-20.07); HR: 0·79 (95% CI, 0.52-1.21); P=0.28]. Patients in the experimental arm showed higher incidence of non-neutropenic fever (18.5%), autoimmunity signs (18.5%), an increase in the number of monocytes, eosinophils, CD4(+) T lymphocytes, natural killer cells, and a decrease in immunoregulatory (CD3(+)CD4(+)CD25(+)FoxP3(+)) T cells. Taken together, these findings provide proof-of-principle that GOLFIG chemoimmunotherapy may represent a novel reliable option for first-line treatment of mCRC.

Immune-modulating effects of the newest cetuximab-based chemoimmunotherapy regimen in advanced colorectal cancer patients.

Cetuximab is a human-murine chimeric monoclonal antibody to the epidermal growth factor receptor, active for advanced colorectal cancer treatment in combination with chemotherapy. Cetuximab mainly acts by inhibiting epidermal growth factor receptor-mediated pathways in cancer cells; however, in the human host, its IgG1 backbone may offer additional antitumor activity that includes FcγRs-mediated antibody-dependent cell cytotoxicity, phagocytosis, cross priming, and tumor-specific T-cell-mediated immune response. These mechanisms are still under active investigation. At this purpose, we have performed an immunologic investigation in advanced colon cancer patients enrolled in an ongoing phase II trial aimed to test the toxicity and the biological and antitumor activity of a novel biochemotherapy regimen combining polychemotherapy with gemcitabine, irinotecan, levofolinic acid, and fluorouracil with cetuximab and with subcutaneous low-dose metronomic aldesleukin (GILFICet regimen). The peripheral blood mononuclear cells of the first 20 patients enrolled in the GILFICet trial were collected at baseline and after 6 treatment cycles and examined for immune-phenotype change by flow cytometry. Colon cancer-specific T-cell lines were also generated ex vivo from these samples and subsequently characterized for immune phenotype, functional activity, and antigen specificity. We found a treatment-related increase of circulating dendritic cells, natural killer cells, central memory T cells, and activated T cells with a T-helper 1 (Th1)-cytotoxic phenotype. In addition, the ex-vivo characterization of antigen-specific T cells derived from the treated patients revealed a significant increase in proliferating cytotoxic T-lymphocyte precursors specific for carcinoembryonic antigen and thymidylate synthase derivative epitope peptides. On these basis, we concluded that the GILFICet regimen exerts substantial immune-modulating activity that significantly affects tumor antigen-specific T-cell compartment with potential antitumor activity.

Phase II trial of bevacizumab and dose/dense chemotherapy with cisplatin and metronomic daily oral etoposide in advanced non-small-cell-lung cancer patients.

Bevacizumab, is a humanized monoclonal antibody to vasculo-endothelial-growth-factor, with anticancer activity in non-small-cell-lung cancer (NSCLC) patients. Our previous results from a dose/finding phase I trial in NSCLC patients, demonstrated the anti-angiogenic effects and toxicity of a newest bevacizumab-based combination with fractioned cisplatin and daily oral etoposide. We designed a phase II trial to evaluate in advanced NSCLC patients the antitumor activity and the safety of this novel regimen. In particular, 45 patients (36 males and 9 females), with a mean age of 54 years, an ECOG ≤ 2, stage IIIB/IV and NSCLC (28 adenocarcinomas, 11 squamous-cell carcinomas, 2 large-cell carcinomas, 4 undifferentiated carcinomas), were enrolled. They received cisplatin (30 mg/sqm, days 1-3), oral etoposide (50 mg, days 1-15) and bevacizumab (5 mg/kg, day 3) every three weeks (mPEBev regimen). Patients who achieved an objective response or stable disease received maintenance treatment with bevacizumab in combination with erlotinib until progression. Grade I-II hematological, mucosal toxicity and alopecia were the most common adverse events. The occurrence of infections (17%), thromboembolic events (4.4%) and severe mood depression (6.7%) was also recorded. A partial response was achieved in 31 (68.8%) patients, disease remained stable in 8 (17.8%), and disease progressed in 6 (13.3%) with a progression-free-survival of 9.53 months (95%CI, 7.7-11.46). Our bio-chemotherapy regimen resulted very active in advanced NSCLC, however, the toxicity associated with the treatment requires strict selection of the patients to enroll in future studies.