Supra-additive effect with concurrent paclitaxel and cisplatin in vulvar squamous cell carcinoma in vitro

Immune checkpoint inhibitors reverse tolerogenic mechanisms induced by melanoma targeted radionuclide therapy

In line with the ongoing phase I trial (NCT03784625) dedicated to melanoma targeted radionuclide therapy (TRT), we explore the interplay between immune system and the melanin ligand [¹³¹I]ICF01012 alone or combined with immunotherapy (immune checkpoint inhibitors, ICI) in preclinical models. Here we demonstrate that [¹³¹I]ICF01012 induces immunogenic cell death, characterized by a significant increase in cell surface-exposed annexin A1 and calreticulin. Additionally, [¹³¹I]ICF01012 increases survival in immunocompetent mice, compared to immunocompromised (29 vs. 24 days, p = 0.0374). Flow cytometry and RT-qPCR analyses highlight that [¹³¹I]ICF01012 induces adaptive and innate immune cell recruitment in the tumor microenvironment. [¹³¹I]ICF01012 combination with ICIs (anti-CTLA-4, anti-PD-1, anti-PD-L1) has shown that tolerance is a main immune escape mechanism, whereas exhaustion is not present after TRT. Furthermore, [¹³¹I]ICF01012 and ICI combination has systematically resulted in a prolonged survival (p < 0.0001) compared to TRT alone. Specifically, [¹³¹I]ICF01012 + anti-CTLA-4 combination significantly increases survival compared to anti-CTLA-4 alone (41 vs. 26 days; p = 0.0011), without toxicity. This work represents the first global characterization of TRT-induced modifications of the antitumor immune response, demonstrating that tolerance is a main immune escape mechanism and that combining TRT and ICI is promising.

Targeting DNA repair by coDbait enhances melanoma targeted radionuclide therapy

Radiolabelled melanin ligands offer an interesting strategy for the treatment of disseminated pigmented melanoma. One of these molecules, ICF01012 labelled with iodine 131, induced a significant slowing of melanoma growth. Here, we have explored the combination of [¹³¹I]ICF01012 with coDbait, a DNA repair inhibitor, to overcome melanoma radioresistance and increase targeted radionuclide therapy (TRT) efficacy. In human SK-Mel 3 melanoma xenograft, the addition of coDbait had a synergistic effect on tumor growth and median survival. The anti-tumor effect was additive in murine syngeneic B16Bl6 model whereas coDbait combination with [¹³¹I]ICF01012 did not increase TRT side effects in secondary pigmented tissues (e.g. hair follicles, eyes). Our results confirm that DNA lesions induced by TRT were not enhanced with coDbait association but, the presence of micronuclei and cell cycle blockade in tumor shows that coDbait acts by interrupting or delaying DNA repair. In this study, we demonstrate for the first time, the usefulness of DNA repair traps in the context of targeted radionuclide therapy.

Multi-drug delivery nanocarriers for combination therapy

The main focus of this review is to discuss recent advances in nanoparticle-based multi-drug delivery platforms towards combination therapy.

A preclinical study combining the DNA repair inhibitor Dbait with radiotherapy for the treatment of melanoma

Melanomas are highly radioresistant tumors, mainly due to efficient DNA double-strand break (DSB) repair. Dbait (which stands for DNA strand break bait) molecules mimic DSBs and trap DNA repair proteins, thereby inhibiting repair of DNA damage induced by radiation therapy (RT). First, the cytotoxic efficacy of Dbait in combination with RT was evaluated in vitro in SK28 and 501mel human melanoma cell lines. Though the extent of RT-induced damage was not increased by Dbait, it persisted for longer revealing a repair defect. Dbait enhanced RT efficacy independently of RT doses. We further assayed the capacity of DT01 (clinical form of Dbait) to enhance efficacy of “palliative” RT (10 × 3 Gy) or “radical” RT (20 × 3 Gy), in an SK28 xenografted model. Inhibition of repair of RT-induced DSB by DT01 was revealed by the significant increase of micronuclei in tumors treated with combined treatment. Mice treated with DT01 and RT combination had significantly better tumor growth control and longer survival compared to RT alone with the “palliative” protocol [tumor growth delay (TGD) by 5.7-fold; median survival: 119 vs 67 days] or the “radical” protocol (TGD by 3.2-fold; median survival: 221 vs 109 days). Only animals that received the combined treatment showed complete responses. No additional toxicity was observed in any DT01-treated groups. This preclinical study provides encouraging results for a combination of a new DNA repair inhibitor, DT01, with RT, in the absence of toxicity. A first-in-human phase I study is currently under way in the palliative management of melanoma in-transit metastases (DRIIM trial).

The additive damage model: a mathematical model for cellular responses to drug combinations

Mathematical models to describe dose-dependent cellular responses to drug combinations are an essential component of computational simulations for predicting therapeutic responses. Here, a new model, the additive damage model, is introduced and tested in cases where varying concentrations of two drugs are applied with a fixed exposure schedule. In the model, cell survival is determined by whether cellular damage, which depends on the concentrations of the drugs, exceeds a lethal threshold, which varies randomly in the cell population with a prescribed statistical distribution. Cellular damage is assumed to be additive, and is expressed as a sum of separate terms for each drug. Each term has a saturable dependence on drug concentration. The model has appropriate behavior over the entire range of drug concentrations, and is predictive, given single-agent dose-response data for each drug. The proposed model is compared with several other models, by testing their ability to fit 24 data sets for platinum-taxane combinations and 21 data sets for various other combinations. The Akaike Information Criterion is used to assess goodness of fit, taking into account the number of unknown parameters in each model. Overall, the additive damage model provides a better fit to the data sets than any previous model. The proposed model provides a basis for computational simulations of therapeutic responses. It predicts responses to drug combinations based on data for each drug acting as a single agent, and can be used as an improved null reference model for assessing synergy in the action of drug combinations.

An unexpected complete remission of advanced intestinal-type vulvar adenocarcinoma after neoadjuvant chemotherapy: a case report and a literature review

Vulvar cancer represents approximately 3%-5% of all gynecological malignancies. Squamous cell carcinoma is the most frequent histotype, whereas melanomas, adenocarcinomas, basal cell carcinomas, and sarcomas are much less common. Intestinal-type adenocarcinoma is a rare variant of vulvar carcinoma with only few cases found in the literature. The origin of this neoplasia is still much debated, but the most reliable hypothesis is the origin from cloacal remnants that may persist in the adult in different organs. Because of its extremely low incidence, the optimal management of this kind of vulvar cancer is still debated. We report the case of a woman affected by advanced intestinal-type vulvar adenocarcinoma, who achieved a complete clinical and pathological response after neoadjuvant chemotherapeutic treatment with platinum and paclitaxel.

Use of Nanotechnology to Develop Multi-Drug Inhibitors For Cancer Therapy

Therapeutic agents that inhibit a single target often cannot combat a multifactorial disease such as cancer. Thus, multi-target inhibitors (MTIs) are needed to circumvent complications such as the development of resistance. There are two predominant types of MTIs, (a) single drug inhibitor (SDIs) that affect multiple pathways simultaneously, and (b) combinatorial agents or multi-drug inhibitors (MDIs) that inhibit multiple pathways. Single agent multi-target kinase inhibitors are amongst the most prominent class of compounds belonging to the former, whereas the latter includes many different classes of combinatorial agents that have been used to achieve synergistic efficacy against cancer. Safe delivery and accumulation at the tumor site is of paramount importance for MTIs because inhibition of multiple key signaling pathways has the potential to lead to systemic toxicity. For this reason, the development of drug delivery mechanisms using nanotechnology is preferable in order to ensure that the MDIs accumulate in the tumor vasculature, thereby increasing efficacy and minimizing off-target and systemic side effects. This review will discuss how nanotechnology can be used for the development of MTIs for cancer therapy and also it concludes with a discussion of the future of nanoparticle-based MTIs as well as the continuing obstacles being faced during the development of these unique agents.’

Drug ratio-dependent antagonism: a new category of multidrug resistance and strategies for its circumvention

A newly identified form of multidrug resistance (MDR) in tumor cells is presented, pertaining to the commonly encountered resistance of cancer cells to anticancer drug combinations at discrete drug:drug ratios. In vitro studies have revealed that whether anticancer drug combinations interact synergistically or antagonistically can depend on the ratio of the combined agents. Failure to control drug ratios in vivo due to uncoordinated pharmacokinetics could therefore lead to drug resistance if tumor cells are exposed to antagonistic drug ratios. Consequently, the most efficacious drug combination may not occur at the typically employed maximum tolerated doses of the combined drugs if this leads to antagonistic ratios in vivo after administration and resistance to therapeutic effects of the drug combination. Our approach to systematically screen a wide range of drug ratios and concentrations and encapsulate the drug combination in a liposomal delivery vehicle at identified synergistic ratios represents a means to mitigate this drug ratio-dependent MDR mechanism. The in vivo efficacy of the improved agents (CombiPlex formulations) is demonstrated and contrasted with the decreased efficacy when drug combinations are exposed to tumor cells in vivo at antagonistic ratios.

Effect of epidermal growth factor receptor inhibitor alone and in combination with cisplatin on growth of vulvar cancer cells

A recent study reported on the efficacy of the EGFR inhibitor on locally advanced vulvar cancer. The aim of this study was to evaluate the effect of an EGFR tyrosine kinase inhibitor (AG1478) alone and in combination with cisplatin on vulvar cancer cells (A431 and SW962). We detected overexpression of EGFR in A431 cells and low expression in SW962 cells. We found that the growth inhibitory effect of AG1478 was dependent upon the expression level of EGFR. The combined treatment of AG1478 with cisplatin failed to exert any synergistic or additive effect in either cell line. In the EGFR signaling pathway, AG1478 decreased the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) in parallel with decreased activity of EGFR in A431 cells, while no changes in ERK and Akt were observed in SW962 cells. The combination of AG1478 with cisplatin completely inhibited the phosphorylation of ERK and Akt in A431 cells but not in SW962 cells. Cisplatin alone and its combination with AG1478 increased the phosphorylation of p38 and c-Jun N-terminal kinase (JNK) in both cell lines. In summary, AG1478 inhibited the growth activity of vulvar cancer cells, depending upon the expression level of EGFR, by inhibiting the activities of EGFR, Akt, and ERK. Given the absence of synergistic effects from the combination of AG1478 with cisplatin, combination therapy should be considered cautiously.

Ratiometric dosing of anticancer drug combinations: controlling drug ratios after systemic administration regulates therapeutic activity in tumor-bearing mice

Anticancer drug combinations can act synergistically or antagonistically against tumor cells in vitro depending on the ratios of the individual agents comprising the combination. The importance of drug ratios in vivo, however, has heretofore not been investigated, and combination chemotherapy treatment regimens continue to be developed based on the maximum tolerated dose of the individual agents. We systematically examined three different drug combinations representing a range of anticancer drug classes with distinct molecular mechanisms (irinotecan/floxuridine, cytarabine/daunorubicin, and cisplatin/daunorubicin) for drug ratio-dependent synergy. In each case, synergistic interactions were observed in vitro at certain drug/drug molar ratio ranges (1:1, 5:1, and 10:1, respectively), whereas other ratios were additive or antagonistic. We were able to maintain fixed drug ratios in plasma of mice for 24 hours after i.v. injection for all three combinations by controlling and overcoming the inherent dissimilar pharmacokinetics of individual drugs through encapsulation in liposomal carrier systems. The liposomes not only maintained drug ratios in the plasma after injection, but also delivered the formulated drug ratio directly to tumor tissue. In vivo maintenance of drug ratios shown to be synergistic in vitro provided increased efficacy in preclinical tumor models, whereas attenuated antitumor activity was observed when antagonistic drug ratios were maintained. Fixing synergistic drug ratios in pharmaceutical carriers provides an avenue by which anticancer drug combinations can be optimized prospectively for maximum therapeutic activity during preclinical development and differs from current practice in which dosing regimens are developed empirically in late-stage clinical trials based on tolerability.

Old and new perspectives in the management of high-risk, locally advanced or recurrent, and metastatic vulvar cancer

During the last decades there has been a continuing evolution in the surgical approach of squamous cell carcinoma of the vulva that has been traditionally treated with radical vulvectomy and bilateral inguinal-femoral lymphadenectomy. Patients with T1 tumour are usually treated with radical local excision, if the lesion is unifocal and the remainder of the vulva is normal. Patients with T1a disease have no risk of groin metastases and do not need lymphadenectomy, whereas those with T1b disease need ipsilateral inguinal-femoral lymphadenectomy if the lesion is lateral, and bilateral lymphadenectomy if the lesion is midline. Modifications of the surgical technique of deep femoral lymphadenectomy and the mapping of sentinel node can offer new interesting therapeutic perspectives. Postoperative adjuvant pelvic and groin irradiation is warranted for patients with two or more or macroscopically involved groin nodes. Locally advanced squamous cell carcinoma of the vulva has been long surgically treated with en-block radical vulvectomy and bilateral inguinal-femoral lymphadenectomy plus partial resection of urethra, vagina or anum, or by exenteration, with severe postsurgical complications, poor quality of life, and unsatisfactory survival rates. 5-Fluorouracil [5-FU] or 5-FU- and cisplatin-based chemotherapy concurrent with irradiation followed by tailored surgery represents an attractive therapeutic option for advanced disease, planned to avoid such ultra-radical surgical procedures and, hopefully, to improve patient outcome. Chemotherapy has also been used in neoadjuvant setting, with contrasting and generally unsatisfactory results, and in palliative treatment of patients with distant metastases. Surgery is the primary treatment also for vulvar malignancies other than squamous cell carcinoma, whereas the clinical usefulness of adjuvant irradiation or chemotherapy is still to be defined. Primary chemoradiation can be also used for advanced carcinoma of the Bartholin gland or for advanced adenocarcinoma associated with extramammary Paget's disease. The drugs used for chemotherapy of metastatic melanomas or sarcomas of the vulva are the same employed for the melanomas or sarcomas developed in other sites.

Combination of paclitaxel and carboplatin as second-line therapy for patients with metastatic melanoma

BACKGROUND

Patients with metastatic melanoma (MM) have very few therapy options. Based on reports of responses to paclitaxel and carboplatin (PC), 31 patients with MM were treated with PC.

METHODS

Data regarding patients treated with PC were abstracted from medical records. Clinical outcomes as determined by the treating oncologist were used for this analysis. Response determination was retrospectively confirmed using Response Evaluation Criteria in Solid Tumors (RECIST).

RESULTS

Thirty-one patients with MM were treated with PC. Patients had a median of 2 previous therapies, with the majority (29; 94%) having failed prior temozolomide (TMZ) or dacarbazine (DTIC) therapy. The most commonly used regimen was weekly paclitaxel (at a dose of 100 mg/m(2)) and carboplatin (area under the curve 2) administered on Days 1, 8, and 15 of a 28-day cycle. An objective partial response was noted in 8 patients (26%) with an additional 6 patients (19%) having stable disease; therefore, a clinical benefit was noted in 45% of those patients treated. The median time to disease progression for the entire group was 3 months (range, 0-7 mos), with a median overall survival of 7.8 months (range, 1-14 mos). The clinical benefit derived by the 14 patients, which lasted for a median of 5.7 months (range, 2.5-7.3 mos), was considered to be clinically significant. At the time of last follow-up, eight patients continued to receive PC therapy.

CONCLUSIONS

The PC combination appears to have definite and clinically meaningful activity when used as second-line therapy after TMZ or DTIC. Further evaluation of this regimen, alone or as a 'backbone' for other agents, needs to be considered.