Optimization of a pendant-shaped PEGylated linker for antibody-drug conjugates.

In this work, we conceived and developed antibody-drug conjugates (ADCs) that could efficiently release the drug after enzymatic cleavage of the linker moiety by tumoral proteases. The antibody-drug linkers we used are the result of a rational optimization of a previously reported PEGylated linker, PUREBRIGHT® MA-P12-PS, which showed excellent drug loading capacities but lacked an inbuilt drug discharge mechanism, thus limiting the potency of the resulting ADCs. To address this limitation, we chose to incorporate a protease-sensitive trigger into the linker to favor the release of a "PEGless" drug inside the tumor cells and, therefore, obtain potent ADCs. Currently, most marketed ADCs are based on the Val-Cit dipeptide followed by a self-immolative spacer for releasing the drug in its unmodified form. Here, we selected two untraditional peptide sequences, a Phe-Gly dipeptide and a Val-Ala-Gly tripeptide and placed one or the other in between the drug on one side (N-terminus) and the rest of the linker, including the PEG moiety, on the other side (C-terminus), without a self-immolative group. We found that both linkers responded to cathepsin B, a reference lysosomal enzyme, and liberated a PEG-free drug catabolite, as desired. We then used the two linkers to generate ADCs based on trastuzumab (a HER2-targeting antibody) and DM1 (a microtubule-targeted cytotoxic agent) with an average drug-to-antibody ratio (DAR) of 4 or 8. The ADCs showed restored cytotoxicity in vitro, which was proportional to the DM1 loading and generally higher for the ADCs bearing Val-Ala-Gly in their structure. In an ovarian cancer mouse model, the DAR 8 ADC based on Val-Ala-Gly behaved better than Kadcyla® (an approved ADC of DAR 3.5 used as control throughout this study), leading to a higher tumor volume reduction and more prolonged median survival. Taken together, our results depict a successful linker optimization process and encourage the application of the Val-Ala-Gly tripeptide as an alternative to other existing protease-sensitive triggers for ADCs.

A new schedule of one week on/one week off temozolomide as second-line treatment of advanced neuroendocrine carcinomas (TENEC-TRIAL): a multicenter, open-label, single-arm, phase II trial.

BACKGROUND: There is no consensus on the second-line treatment of patients with progressive high-grade neuroendocrine neoplasms (NENs G3) and large-cell lung neuroendocrine carcinoma. These patients generally have poor performance status and low tolerance to combination therapy. In this trial, we aim to evaluate the efficacy and safety of temozolomide given every other week in patients with advanced platinum-pretreated NENs G3. PATIENTS AND METHODS: This trial is an open-label, non-randomized, phase II trial. Patients with platinum-pretreated metastatic neuroendocrine carcinoma were treated with 75 mg/m2/day of temozolomide for 7 days, followed by 7 days of no treatment (regimen one week on/one week off). The primary endpoint was the overall response rate. Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety and tolerability. This study is registered with ClinicalTrials.gov, NCT04122911. RESULTS: From 2017 to 2020, 38 patients were enrolled. Among the patients with determined Ki67, 12 out of 36 (33.3%) had a Ki67 index <55% and the remaining 24 out of 36 (66.6%) had an index ≥55%. Overall response rate was 18% (7/38), including one complete response and six partial responses. The median PFS was 5.86 months [95% confidence interval (CI) 4.8 months-not applicable) and the median OS was 12.1 months (95% CI 5.6-20.4 months). The 1-year PFS rate was 37%. No statistically significant difference in median PFS [hazard ratio 1.3 (95% CI 0.6-2.8); P = 0.44] and median OS [hazard ratio 1.1 (95% CI 0.5-2.4); P = 0.77] was observed among patients with Ki67 <55% versus ≥55%. Only G1-G2 adverse events were registered, the most common being G1 nausea, diarrhea and abdominal pain. CONCLUSION: One week on/one week off temozolomide shows promising activity in patients with poorly differentiated NEN. The good safety profile confirmed the possibility of using this scheme in patients with poor performance status.

Targeted therapy for advanced hepatocellular cancer in the elderly: focus on sorafenib.

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide. Worldwide progressive population aging demands consensus development for decision making when treating elderly patients. Age itself might not be a critical determinant for the selection of a therapeutic option. In the past few years, the mechanisms of hepato-carcinogenesis have been elucidated, and the involvement of a number of pathways, including angiogenesis, aberrant signal transduction, and dysregulated cell cycle control, have been demonstrated, leading to evaluation of the activity and toxicity of some of the new molecularly targeted agents. Sorafenib was demonstrated to significantly increase the survival of patients with advanced HCC in two prospective, randomized, placebo-controlled trials. Subsequently, a number of retrospective or prospective studies have indicated that the effectiveness of sorafenib therapy in the treatment of HCC is similar in elderly and non-elderly patients. The aim of this review is to describe the impact of age on the effects of sorafenib-targeted therapy in patients with HCC, and the next treatment options with new targeted agents (everolimus, tivantinib, linifanib, etc.).

Medical treatment of hepatocellular carcinoma.

The management of hepatocellular carcinoma (HCC) has substantially changed in the past few decades, the introduction of novel therapies (such as sorafenib) have improved patient survival. Nevertheless, HCC remains the third most common cause of cancer-related deaths worldwide. Decision-making largely relies on evidence-based criteria, as showed in the US and European clinical practice guidelines, which endorse five therapeutic recommendations: resection; transplantation; radiofrequency ablation; chemoembolization; and sorafenib. However, areas still exist in which uncertainty precludes a strong recommendation, such as the role of adjuvant therapies after resection, radioembolization with yttrium-90 or second-line therapies for advanced HCC. Many clinical trials that are currently ongoing aim to answer these questions. The first reported studies, however, failed to identify novel therapeutic alternatives (that is, sunitinib, erlotinib or brivanib). Efforts that focus on the implementation of personalized medicine approaches in HCC will probably dominate research in the next decade.

Follow-up with CA125 after primary therapy of advanced ovarian cancer: in favor of continuing to prescribe CA125 during follow-up.

Serum cancer antigen 125 (CA125) is widely used in ovarian cancer to monitor the effectiveness of therapy both in first line and recurrence. It is also widely used during follow-up, where it is able to identify a percentage of patients with asymptomatic recurrence. Although a recent Medical Research Council (UK)/European Organisation for Research and Treatment of Cancer trial has demonstrated that early chemotherapy in asymptomatic patients based only on CA125 increase does not prolong survival, we still believe that CA125 monitoring should be prescribed to patients during follow-up. In fact, it can help to identify patients who should undergo radiology in order to select those that can benefit from surgery or from early treatment before the onset of symptoms, which are usually related to an excessive disease burden. The delay of disease symptoms, such as those associated with the appearance of ascites or bowel occlusion, is in our view an important goal of our treatment of recurrence. Moreover, research should be done in patients with asymptomatic CA125 increase in order to identify more effective therapies that will improve survival. Finally, the reliability of CA125 as a surrogate of response under treatment with biological agents should be validated in prospective trials.

A phase I-II study of elacytarabine (CP-4055) in the treatment of patients with ovarian cancer resistant or refractory to platinum therapy.

PURPOSE: Treatment of patients with recurrent ovarian cancer remains a challenge, and there is a need for new and more effective agents. A phase I-II study was designed to determine the recommended dose (RD) and the anti-tumour effect of a prolonged administration of elacytarabine, the elaidic ester of cytarabine, in patients with refractory/resistant recurrent ovarian cancer. EXPERIMENTAL DESIGN: The primary objective of the dose escalation phase I part was to determine the RD for elacytarabine when given twice for five consecutive days in a 4-week schedule, D1-5 and D8(+2)-12(+2) q4w. Three to six patients were to be enrolled at each dose level. The start dose was elacytarabine 75 mg/m(2)/day. The phase II part was designed as a two-step study based on response. RESULTS: A total of 28 patients entered the study, 17 patients in the phase I part and 11(#) patients in phase II. Three dose levels were tested: 75 mg/m(2)/day in 3 patients, 100 mg/m(2)/day in 7 + 11(#) patients, and 125 mg/m(2)/day in 7 patients. Three (17.6%) patients in phase I experienced a dose limiting toxicity (DLT), all at the 125 mg/m(2)/day dose level, establishing the lower dose of 100 mg/m(2)/day as the RD. The DLTs were neutropenia grade 4 according to the Common Terminology Criteria for Adverse Events (CTCAE) and thrombocytopenia grade 4 (2 patients), and vomiting grade 2 with hospitalisation and hypokalaemia grade 3 (1 patient). The best response was a clinically meaningful stabilization observed in 3 patients. In two of them, the disease stabilization exceeded the previous platinum-free interval (PFI). CONCLUSIONS: The RD for elacytarabine was 100 mg/m(2)/day, D1-5 and D8-12 q4w. The safety profile was comparable to the safety profiles reported in previous clinical studies with elacytarabine in solid tumours. Despite some longer-lasting disease stabilisations, two of them exceeding the previous progression-free interval, further investigations of elacytarabine in the ovarian cancer indication are not warranted.

Neo-adjuvant treatment of rectal cancer with capecitabine and oxaliplatin in combination with radiotherapy: a phase II study.

BACKGROUND: Preoperative chemoradiation is now standard treatment for stages II-III rectal cancer. Capecitabine (CAP) and oxaliplatin (OX) are synergistic with radiotherapy (RT) and active in colorectal neoplasms. PATIENTS AND METHODS: Two cycles of CAP 825 mg/m(2) b.i.d. (days 1-14) and OX 50 mg/m(2) (days 1 and 8) every 3 weeks were given concomitantly with pelvic conformal RT (45 Gy). Patients with a > or =T3 and/or node-positive rectal tumour were eligible. The pathologic tumour response was defined according to the tumour regression grade (TRG) scale. RESULTS: Forty-six patients were enrolled. Gastrointestinal adverse events were mostly G1-G2; only two patients experienced G3 vomiting and diarrhoea and six patients had G1 peripheral neuropathy. Haematological toxicity was rare. G2 proctitis and anal pain occurred in two patients. Pathological complete response (TRG1) was observed in nine patients (20.9%; 95% CI 8.7%-33.1%); TRG2 in 19 patients (44.2%); TRG3 in 12 patients (27.9%); and TRG4 in three patients (7%). Overall, nine patients recurred: five with distant metastases, one with local recurrence, and three with both local recurrence and distant metastases. CONCLUSIONS: CAP-OX-RT as preoperative treatment for rectal cancer induces a remarkable rate of complete or near-complete pathologically documented response and is well tolerated.

Analysis of prognostic factors in patients with refractory anemia with excess of blasts (RAEB) reclassified according to WHO proposal.

The WHO classification subdivides the FAB RAEB category into RAEB-1 (bone marrow (BM) blasts <10%, peripheral blasts <5%) and RAEB-2 (bone marrow blasts >10% and peripheral blasts >5%). We reclassified according to WHO criteria 228 RAEB patients and analysed them in terms of haematological, karyotypic and prognostic features. We used the database of 680 MDS patients referred to our Institution from 1990 to 2000. Clinical features at presentation, such as sex, age, leukocyte count, polymorphonuclear cell count (PMN), platelet count, haemoglobin level, presence of one or more lineage dysplasia were tested in univariate and multivariate analysis in the two groups of RAEB-1 and RAEB-2 reclassified patients. In multivariate analysis we identified prognostic significant factors in the two patient groups, which consisted of age >70 years and platelet count <100 x 10(9)l(-1) for RAEB-1 category, while for RAEB-2 group parameters negatively influencing survival and risk of progression were haemoglobin <10g/dl, platelet count <100 x 10(9)l(-1), bone marrow blastosis >15% and complex karyotype. We also found differences in cytogenetic data (more balanced translocations and complex karyotypes in RAEB-2 group, p=0.02), and in survival (23.3 months in RAEB-1 vs. 16.1 months in RAEB-2 group, p=0.001). WHO classification provides valuable prognostic information for RAEB patient population, and can identify those subjects with more unfavourable prognosis who should be offered alternative therapeutic strategies.

Chronic myelomonocytic leukemia with antecedent refractory anemia with excess blasts: further evidence for the arbitrary nature of current classification systems.

From a retrospective analysis of our series of myelodysplastic patients, we found 16 patients who were initially diagnosed as having a refractory anemia with excess of blasts (RAEB) according to FAB criteria, but later on (median time 4 months, range 2-8) developed a peripheral monocytosis >1 x 10(9)/L, leading to a disease re-classification into a dysplastic type of chronic myelomonocytic leukemia (MD-CMML). Analysis of clinical and prognostic aspects in this subgroup of patients as compared with those of primarily diagnosed MD-CMML patients, showed some significant differences in Hb level, platelet count, percentage of immature circulating precursor (IPC), bone marrow blastosis and trilineage dysplasia. Median survival for present group of patients was 33 months compared with 20 months for MD-CMML. Different prognostic scores were applied for evaluation of risk distribution and relative impact on survival prediction. We suggest on a possible atypical presentation of CMML and indicate a careful attention to be addressed to myelodysplastic patients who develop peripheral monocytosis, who might have a CMML variant, with more favourable prognosis and prolonged survival. Furthermore, we believe this is a further evidence for the arbitrary nature of current classification systems, which definitely exclude CMML from myelodysplastic syndromes.

The highway code of T cell trafficking.

Coordinated migratory events are required for the development of effective and regulated immunity. Naïve T lymphocytes are programmed to recirculate predominantly in secondary lymphoid tissue by non-specific stimuli. In contrast, primed T cells must identify specific sites of antigen location in non-lymphoid tissue to exert targeted effector responses. Following priming, T cells acquire the ability to establish molecular interactions mediated by tissue-selective integrins and chemokine receptors (homing receptors) that allow their access to specific organs, such as the skin and the gut. Recent studies have shown that an additional level of specificity is provided by the induction of specific T cell migration into the tissue following recognition of antigen displayed by the endothelium. In addition, co-stimulatory signals (such as those induced by CD28 and CTLA-4 molecules) have been shown not only to regulate T cell activation and differentiation, but also to orchestrate the anatomy of the ensuing T cell response.