Harnessing tumor immunity with cytotoxics: T cells monitoring in mice bearing lung tumors treated with anti-VEGF and pemetrexed-cisplatin doublet

BACKGROUND

Successful immunotherapy is restricted to some cancers only, and combinatorial strategies with other drugs could help to improve their efficacy. Here, we monitor T cells in NSCLC model after treatment with cytotoxics (CT) and anti-VEGF drugs, to understand when immune checkpoint inhibitors should be best associated next.

METHODS

In vivo study was performed on BALB/c mice grafted with KLN205 cells. Eight treatments were tested including control, cisplatin and pemetrexed as low (LD CT) and full (MTD CT) dose as single agents, flat dose anti-VEGF and the association anti-VEGF + CT. Full immunomonitoring was performed by flow cytometry on tumor, spleen and blood over 3 weeks.

RESULTS

Immunomodulatory effect was dependent upon both treatments and time. In tumors, combination groups shown numerical lower Treg cells on Day 21. In spleen, anti-VEGF and LD CT group shown higher CD8/Treg ratio on Day 7; on Day 14, higher T CD4 were observed in both combination groups. Finally, in blood, Tregs were lower and CD8/Treg ratio higher, on Day 14 in both combination groups. On Day 21, CD4 and CD8 T cells were higher in the anti-VEGF + MTD CT group.

CONCLUSIONS

Anti-VEGF associated to CT triggers notable increase in CD8/Tregs ratio. Regarding the scheduling, a two-week delay after using anti-VEGF and CT could be the best sequence to optimize antitumor efficacy.

Prototyping Trastuzumab Docetaxel Immunoliposomes with a New FCM-Based Method to Quantify Optimal Antibody Density on Nanoparticles

Developing targeted nanoparticles is a rising strategy to improve drug delivery in oncology. Antibodies are the most commonly used targeting agents. However, determination of their optimal number at the surface remains a challenging issue, mainly due to the difficulties in measuring precisely surface coating levels when prototyping nanoparticles. We developed an original quantitative assay to measure the exact number of coated antibodies per nanoparticle. Using flow cytometry optimized for submicron particle analysis and beads covered with known amounts of human IgG-kappa mimicking various amounts of antibodies, this new method was tested as part of the prototyping of docetaxel liposomes coated with trastuzumab against Her2+ breast cancer. This quantification method allowed to discriminate various batches of immunoliposomes depending on their trastuzumab density on nanoparticle surface (i.e., 330 (Immunoliposome-1), 480 (Immunoliposome-2) and 690 (Immunoliposome-3), p = 0.004, One-way ANOVA). Here we showed that optimal number of grafted antibodies on nanoparticles should be finely tuned and highest density of targeting agent is not necessarily associated with highest efficacy. Overall, this new method should help to better prototype third generation nanoparticles.

Micafungin as primary antifungal prophylaxis in patients presenting with acute myeloid leukemia

OBJECTIVE

To study the efficacy and safety of micafungin for prophylaxis of invasive fungal infections in patients undergoing induction chemotherapy for acute myeloid leukemia.

PATIENTS AND METHODS

A prospective observational single-center study of 41 patients from the hematology department between May 2012 and April 2015. Micafungin was administered once daily from the first day of induction chemotherapy to the end of the neutropenic phase.

RESULTS

Neither Candida nor Aspergillus infection was documented in our 41 patients from the first day of micafungin infusion to the end of the neutropenic phase. Patients were followed for three months after discontinuation of micafungin and none of them contracted an invasive fungal infection. Only one patient presented with grade III-IV hepatic and ionic toxicities.

CONCLUSION

Micafungin is associated with a good safety profile and is an interesting option for preventing invasive fungal infections in the high-risk population of patients presenting with hematological disorders.

Liposome-encapsulated anticancer drugs: still waiting for the magic bullet?

Anticancer drugs are essential agents in the global strategy developed to fight cancer. Still, narrow therapeutic indices, erratic pharmacokinetics profiles and lack of selectivity towards malignant tissues often hamper their efficacy at the bedside, when they not cause severe toxicities. In this respect, developing innovative drug delivery strategies that would selectively target malignant tissues is still an ongoing story, both in experimental and in clinical oncology. Delivery systems such as liposomes are usually required when an existing formulation is not satisfactory, because encapsulation is expected to provide higher therapeutic efficacy and safety. Such significant improvement in therapeutic efficacy and/or therapeutic indices has already been achieved in patients with some liposome-encapsulated drugs such as anthracyclines. It is now possible to develop a wide range of vectors varying in size, composition, and surface morphology suitable for a variety of therapeutic applications, including for targeting tumor tissues. Reformulation of anticancer drugs in liposomes remains a challenging opportunity to stretch the therapeutic indices of many cytotoxic drugs, through the optimization of their distribution in the body. Despite these promising and exciting perspectives in oncology, to date only few drugs (e.g., anthracyclines) have actually made their way as liposomes from the bench to the bedside. However, as target therapies have brought a new hope in the cancer war in the 2000's, developing now targeted delivery systems is more and more seen as the next step to further improve clinical outcome in cancer patients. This review covers the achievements, limits, and new expectancies of anticancer drugs as candidates for liposomal encapsulation.

In vitro and in vivo reversal of resistance to 5-fluorouracil in colorectal cancer cells with a novel stealth double-liposomal formulation

Drug resistance is a major cause of treatment failure in cancer chemotherapy, including that with the extensively prescribed antimetabolite, 5-fluorouracil (5-FU). In this study, we tried to reverse 5-FU resistance by using a double-punch strategy: combining 5-FU with a biochemical modulator to improve its tumoural activation and encapsulating both these agents in one same stealth liposome. Experiments carried out in the highly resistant, canonical SW620 human colorectal model showed a up to 80% sensitisation to 5-FU when these cells were treated with our liposomal formulation. Results with this formulation demonstrated 30% higher tumoural drug uptake, better activation with increased active metabolites including critical-5-fluoro-2-deoxyuridine-5-monophosphate, superior inhibition (98%) of tumour thymidylate synthase, and subsequently, higher induction of both early and late apoptosis. Drug monitoring showed that higher and sustained exposure was achieved in rats treated with liposomal formulation. When examined in a xenograft animal model, our dual-agent liposomal formulation caused a 74% reduction in tumour size with a mean doubling in survival time, whereas standard 5-FU failed to exhibit significant antiproliferative activity as well as to increase the lifespan of tumour-bearing mice. Taken collectively, our data suggest that resistance to 5-FU can be overcome through a better control of its intratumoural activation and the use of an encapsulated formulation.