Metronomic delivery of orally available pemetrexed-incorporated colloidal dispersions for boosting tumor-specific immunity

In this study, we developed oral pemetrexed (PMX) for metronomic dosing to enhance antitumor immunity. PMX was electrostatically complexed with positively charged lysine-linked deoxycholic acid (DL) as an intestinal permeation enhancer, forming PMX/DL, to enhance its intestinal permeability. PMX/DL was also incorporated into a colloidal dispersion (CD) comprised of the block copolymer of poly(ethylene oxide) and poly(propylene oxide), and caprylocaproyl macrogol-8 glycerides (PMX/DL-CD). CD-containing PMX/DL complex in a 1:1 molar ratio [PMX/DL(1:1)-CD] showed 4.66- and 7.19-fold greater permeability than free PMX through the Caco-2 cell monolayer and rat intestine, respectively. This resulted in a 282% improvement in oral bioavailability in rats. In addition, low-dose metronomic PMX led to more immunogenic cell death in CT26.CL25 cells compared to high PMX concentrations at the maximum tolerated dose. In CT26.CL25 tumor-bearing mice, oral metronomic PMX/DL-CD elicited greater antitumor immunity not only by enhancing the number of tumor-infiltrating lymphocytes but also by suppressing T cell functions. Oral PMX/DL-CD substantially increased programmed cell death protein ligand-1 (PD-L1) expression on tumor cells compared to the control and PMX-IV groups. This increased antitumor efficacy in combination with anti-programmed cell death protein-1 (aPD-1) antibody in terms of tumor rejection and immunological memory compared to the combination of PMX-IV and aPD-1. These results suggest that oral metronomic scheduling of PMX/DL-CD in combination with immunotherapy has synergistic antitumor effects.

Metronomic palliative chemotherapy in locally advanced, recurrent and metastatic head-and-neck cancer: A single-arm, retrospective study of a regional cancer center of North India (Asia)

Background

Head-and-neck cancer is the most common cancer in developing countries of Southeast Asia. Most of the patients present to the hospital in advanced stage and have a poor prognosis. This study aims to evaluate the efficacy and toxicity profile of oral metronomic chemotherapy (MCT) in the form of methotrexate and celecoxib in locally advanced, recurrent and metastatic head-and-neck cancers.

Materials and Methods

This was a single-arm retrospective observational study that included posttreatment patients with locally advanced, recurrent and metastatic disease in the year 2016 (January 1, to December 31, 2016). A total of 84 patients warranting palliative chemotherapy but not willing to take intravenous chemotherapy were included in the study. The oral MCT schedule consisted of oral celecoxib (200 mg twice daily) and oral methotrexate (15 mg/m²/week). Response evaluation was done using the Response Evaluation Criteria in Solid Tumors criteria version 1.1, and toxicity profile was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03. Descriptive statistics and Kaplan-Meier analysis were performed.

Results

Eighty-four patients, 68 males and 16 females, with a median age of 62 years (range: 35-80 years), were enrolled in the study to receive oral MCT. The Eastern Cooperative Oncology Group performance status was 0-1 in 62 patients and 2-3 in 22 patients. The primary sites of disease were buccal mucosa (18), tongue (22), tonsil (24), lower alveolus (7), hypopharynx (10), and soft palate (3). The best clinical response rate in post oral MCT was seen in the first 4 months (120 days). Objective response was observed in 67% of patients in the form of stable disease (56%) and partial response (11%). Disease progression was observed in 27% of patients. The median follow-up was 192 (6.4 months) days. The median estimated overall survival was 195 (6.5 months) days. The median estimated progression-free survival was 110 (3.6 months) days. Symptomatic relief with respect to pain was reported in about 75% of patients. Eighteen (21%) patients had Grade I-II mucosal reactions. Grade III-IV mucosal reactions were observed in five (6%) patients. Seventy-eight (93%) patients died at the end of the study at 1 year. Dose reduction was required in 15 (18%) patients.

Conclusion

Oral MCT using celecoxib and methotrexate is an effective, economical, and well-tolerated regimen with good pain control and low toxicity profile in patients with locally advanced, recurrent and metastatic head-and-neck cancer.

Intestinal transport mechanism and in vivo anticancer efficacy of a solid oral formulation incorporating an ion-pairing complex of pemetrexed with deoxycholic acid derivative

Objective

The rational combination of immunotherapy with standard chemotherapy shows synergistic clinical activities in cancer treatment. In the present study, an oral powder formulation of pemetrexed (PMX) was developed to enhance intestinal membrane permeability and investigate its application in metronomic chemotherapy in combination with immunotherapy.

Methods

PMX was ionically complexed with a bile acid derivative (N^α-deoxycholyl-l-lysyl-methylester; DCK) as a permeation enhancer and mixed with dispersing agents, such as poloxamer 188 (P188) and Labrasol, to form an amorphous oral powder formulation of PMX/DCK (PMX/DCK-OP).

Results

The apparent permeability (P_app) of PMX/DCK-OP across a Caco-2 cell monolayer was 2.46- and 8.26-fold greater than that of PMX/DCK and free PMX, respectively, which may have been due to the specific interaction of DCK with bile acid transporters, as well as the alteration of membrane fluidity due to Labrasol and P188. Furthermore, inhibition of bile acid transporters by actinomycin D in Caco-2 cell monolayers decreased the P_app of PMX/DCK-OP by 75.4%, suggesting a predominant role of bile acid transporters in the intestinal absorption of PMX/DCK-OP. In addition, caveola/lipid raft-dependent endocytosis, macropinocytosis, passive diffusion, and paracellular transport mechanisms significantly influenced the permeation of PMX/DCK-OP through the intestinal membrane. Therefore, the oral bioavailability of PMX/DCK-OP in rats was 19.8%±6.93%, which was 294% higher than that of oral PMX. Moreover, an in vivo anticancer efficacy study in B16F10 cell-bearing mice treated with a combination of oral PMX/DCK-OP and intraperitoneal anti-PD1 exhibited significant suppression of tumor growth, and the tumor volume was maximally inhibited by 2.03- and 3.16-fold compared to the oral PMX/DCK-OP and control groups, respectively.

Conclusion

These findings indicated the therapeutic potential of a combination of low-dose oral chemotherapy and immunotherapy for synergistic anticancer efficacy.