Oral Metronomic Chemotherapy in Advanced and Metastatic Oral Squamous Cell Carcinoma: A Need of the Hour.

Aim: The present review article aims to compile the best available evidence-based data on oral metronomic chemotherapy (OMCT) including its mechanism of action, its utility, and future directions. Methods: A systematic search was carried out in PubMed database for available English literature from last 10 years between 2011 and 2021. Keyword combinations used were 'Oral Metronomic chemotherapy for oral cancer, mechanism of action of OMCT, Oral metronomic chemotherapy in India, OMCT in recurrent and palliative treatment of oral cancers.' Results: Multitudes of studies have been published recently stating the role of OMCT in head and neck squamous cell carcinoma (HNSCC), but the studies with the category of level of evidence required to advocate OMCT as a recognized therapy are still scarce. On careful stratification of these studies, we found that OMCT has a lot to offer in palliative settings, recurrent, and metastatic HNSCC. There is some limited evidence of its role in adjuvant therapy as maintenance and in neoadjuvant setting. Conclusion: With current evidence, there is a definite role of OMCT in treatment of oral SCC. OMCT can be an alternative in patients who are not tolerable or affordable for standard palliative chemotherapy and also an option for patient who are waiting for surgery. However, results of ongoing and future studies on exact mechanism, indications, and implications of this drug regimen would help in integration OMCT in current standard of therapy.

Triple combination of palliative oral metronomic chemotherapy in recurrent and metastatic epithelial ovarian cancer: A retrospective study.

Background: Ovarian cancer is a leading cause of death from gynecological cancer in the world and in India. This study aims to evaluate the efficacy and toxicity profile of oral metronomic chemotherapy (MCT) in the form of etoposide, cyclophosphamide, and tamoxifen in recurrent and metastatic ovarian cancer. Methods: This was a retrospective observational study that included those post-treatment patients who had the recurrent or metastatic disease after completion of treatment in 2018 at Regional Cancer Centre, Bikaner, Rajasthan. Forty patients who were unfit for further intensive intravenous chemotherapy were included. The oral MCT constituted etoposide, cyclophosphamide, and tamoxifen. Descriptive statistics and Kaplan-Meier analyses were performed. Progression-free survival (PFS) and overall survival (OS) were assessed. Results: Forty women with a median age of 62 (range: 35-80) years were enrolled in the study to receive oral MCT. The Eastern Cooperative Oncology Group-Performance Status (ECOG-PS) was 0-1 in 28 patients and 2-3 in 12 patients. The best clinical response rate post-oral MCT was seen in the first 4 months. Objective response was observed in 24 (60%) of patients in the form of stable disease (19, 47.5%) and partial response (5, 12.5%). Disease progression was observed in 10 (25%) of patients. The median follow-up was 6.4 months (4.5-9.2 months). The median estimated OS was 6.5 months. The median estimated PFS was 3.7 months. Nineteen (47.5%) patients had grade-I/II mucositis. Grade-III/IV mucositis were observed in 9 (22.5%) patients. Thirty-seven (92.5%) patients died at the end of the study at 1 year. Dose reduction was required in 15 (37.5%) patients. Conclusion: Oral MCT was found to be an effective and well-tolerated regime with good symptomatic control and low-moderate toxicity profile in patients with relapsed and metastatic ovarian cancer. However, 22% of patients showed grade-III/IV thrombocytopenia.

The Spectrum of Histomorphological Changes and Pathological Tumor Response following Preoperative Oral Metronomic Chemotherapy in Oral Squamous Cell Carcinoma.

Sithara AravindBackground Oral metronomic chemotherapy (OMCT) represents an emerging concept in cancer treatment involving frequent administration of chemotherapeutic drugs at doses below maximum tolerated doses and with no prolonged drug-free break. OMCT is being tried preoperatively in developing nations with constrained resources to prevent disease progression during the waiting period from diagnosis to surgery (bridge OMCT). The aim of the present study was to assess the spectrum of histomorphological changes and pathological tumor response following bridge OMCT in oral squamous cell carcinoma (OSCC) and to propose a new pathological response scoring system. Materials and Methods A retrospective single-center study comprised of tissue sections of tumor proper and metastatic lymph nodes of 50, locally advanced OSCC patients treated with bridge OMCT, and had completed definitive surgery were analyzed. The present study evaluated the histomorphological features and proposed a new scoring system for pathologic tumor response. The pathologic tumor response was categorized as complete response (pCR), no response (pNR), and partial response (pPR). Results Of the total 50 patients, 2 patients had pCR, 3 had pNR, and 45 patients had pPR as per the new proposed scoring system. Note that 96% of the cases showed no disease progression. Conclusion Bridge OMCT is a novel treatment method that can be used to tide over the waiting period between the diagnosis and surgery in resource-constrained institutions with heavy patient load. This mode of treatment in locally advanced OSCC seems to provide promising results in this setting. Large multicentric trials are warranted to confirm these results.

A novel oral metronomic chemotherapy provokes tumor specific immunity resulting in colon cancer eradication in combination with anti-PD-1 therapy.

In this study, we investigated the immune-modulating effects of a novel metronomic chemotherapy (MCT) featuring combined oral oxaliplatin (OXA) and pemetrexed (PMX) for colon cancer. OXA and PMX were ionically complexed with lysine derivative of deoxycholic acid (DCK), and incorporated into nanoemulsions or colloidal dispersions, yielding OXA/DCK-NE and PMX/DCK-OP, respectively, to improve their oral bioavailabilities. MCT was not associated with significant lymphotoxicity whereas the maximum tolerated dose (MTD) afforded systemic immunosuppression. MCT was associated with more immunogenic cell death and tumor cell MHC-class I expression than was MTD. MCT improved the tumor antigen presentation of dendritic cells and increased the number of functional T cells in the tumor. MCT also helped to enhance antigen-specific memory responses both locally and systemically. By combining MCT with anti-programmed cell death protein-1 (αPD-1) therapy, the tumor volume was suppressed by 97.85 ± 84.88% compared to the control, resulting in a 95% complete response rate. Upon re-challenge, all tumor-free mice rejected secondary tumors, indicating the induction of a tumor specific memory response. Thus, MCT using an OXA and PMX combination, together with αPD-1, successfully treated colon cancer by activating both innate and adaptive immune cells and elicited tumor-specific long-term immune memory while avoiding toxicity caused by MTD treatment.

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.

Modulating tumor immunity by metronomic dosing of oxaliplatin incorporated in multiple oral nanoemulsion.

In this study, a system for oral delivery of oxaliplatin (OXA) was prepared for metronomic chemotherapy to enhance antitumor efficacy and modulate tumor immunity. OXA was complexed with Nα-deoxycholyl-l-lysyl-methylester (DCK) (OXA/DCK) and formulated as a nanoemulsion (OXA/DCK-NE). OXA/DCK-NE showed 3.35-fold increased permeability across a Caco-2 cell monolayer, resulting in 1.73-fold higher oral bioavailability than free OXA. In addition, treatment of the B16F10.OVA cell line with OXA/DCK-NE resulted in successful upregulation of immunogenic cell death (ICD) markers both in vitro and in vivo. In a B16F10.OVA tumor-bearing mouse model, treatment with OXA/DCK-NE substantially impeded tumor growth by 63.9 ± 13.3% compared to the control group, which was also greater than the intravenous (IV) OXA group. Moreover, treatment with a combination of oral OXA/DCK-NE and anti-programmed cell death protein-1 (αPD-1) antibody resulted in 78.3 ± 9.67% greater inhibition compared to controls. More important, OXA/DCK-NE alone had immunomodulatory effects, such as enhancement of tumor antigen uptake, activation of dendritic cells in tumor-draining lymph nodes, and augmentation of both the population and function of immune effector cells in tumor tissue as well as in the spleen; no such effects were seen in the OXA IV group. These observations provide a rationale for combining oral metronomic OXA with immunotherapy to elicit synergistic antitumor effects.

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 (Nα-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 (Papp) 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 Papp 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.

Outcomes of Oral Metronomic Therapy in Patients with Lymphomas.

Oral Metronomic chemotherapy (OMC) is used in patients with lymphoma who may not tolerate intravenous chemotherapy or have refractory disease. It is cheaper, less toxic and easy to administer. Adult patients with lymphoma who received OMC (combination of cyclophosphamide, etoposide and prednisolone) were included in this retrospective analysis. Response assessment was clinical with limited use of radiology. Progression free and overall survival (PFS and OS) were calculated from the time of start of OMC until documentation of disease progression or death. Between 2007 and 2017, 149 patients were given OMC [median age: 62 years (19-87); 94 patients (63.1%) male]. Majority [112 patients (75.2%)] had stage III/IV disease. The most common subtype of lymphoma was diffuse large B cell lymphoma (40.9%). OMC was used at diagnosis in 41 patients (27.5%) and after relapse in 108 patients (72.5%). Overall response rates were 43.9 and 41.7% with clinical CR in 14 (34.1%) and 21 (19.4%) in patients given first line and later lines of OMC respectively. After a median follow up of 12 months (range 1-123 months), median PFS and OS were 10.5 (95% CI 8.6-12.5) and 18.8 (95% CI 12.1-25.5) months respectively. PFS and OS at 12 months were 47.6 and 64.2% respectively. Though OMC is used in many centers in India, there is scanty published information on its efficacy in lymphoma. In this analysis, we demonstrate its activity in a subset of patients with predominantly high-grade and advanced stage NHL. OMC is a useful option in frail patients and a small proportion can achieve deep and long lasting responses.