Low-dose Metronomic Cyclophosphamide Research Articles

Abstract PD11-11: PD11-11 Results from ALICE – Atezolizumab Combined with Immunogenic Chemotherapy in Patients with Metastatic Triple Negative Breast Cancer, a Randomized Phase IIb Trial

Abstract Background: Immune checkpoint inhibitors (CPI) have shown efficacy against metastatic triple negative breast cancer (mTNBC), but only for PD-L1 positive tumors. It is not known if so-called immunogenic chemotherapies may yield clinical relevant synergies with CPI. We addressed these issues, by conducting a trial evaluating atezolizumab (anti-PD-L1) in combination with doxorubicin, which has been reported to provoke immunogenic cell death, and low-dose metronomic cyclophosphamide, which has been reported to counter immunosuppressive cells. The pegylated liposomal form of doxorubicin (PLD) was selected to avoid steroids and allow for long term therapy in responders. To our knowledge, this is the first randomized trial reporting on the concomitant addition of CPI to antracyclines in mTNBC. Methods: The trial enrolled patients with mTNBC and maximum one previous line of chemotherapy in the metastatic setting. Patients were randomized 2:3 into arm A (n=28), receiving chemotherapy alone, or arm B (n=40), receiving chemotherapy in combination with atezolizumab (840 mg every 2nd week). The chemotherapy consisted of PLD (20mg/m2 every 2nd week) + oral cyclophosphamide (cyclo; 50mg/day, 2/4 weeks) in both arms. The per protocol (PP) population was defined as patients receiving > 3 doses of atezolizumab and >2 doses of PLD. The primary efficacy endpoint was progression-free survival (PFS) in the PP population. The protocol power analysis focused on durable response, as measured by 15 months PFS. Safety, a co-primary endpoint, was evaluated in all patients that started therapy (Full Analysis Set; FAS). Secondary endpoints included PFS in FAS, objective response rate (ORR), clinical benefit rate (CBR), durable response rate (>6 months; DRR), overall survival (OS) and biomarkers. PD-L1 status was determined retrospectively by the Ventana SP142 assay, as tumor-infiltrating immune cells with cut-off ≥ 1%. Efficacy data are given in the PP population unless stated otherwise. Hazard ratios (HR) are given with 95% confidence intervals (CI). Results: A total of 68 patients started therapy (FAS), of which 59 were in the PP population and 57% had not received previous chemotherapy in the metastatic setting. PFS was significantly improved in arm B compared to arm A in both the PP population (HR 0.57; CI 0.33-0.99; p=0.0477) and in the FAS (HR 0.56; CI 0.33-0.95; p=0.0326). Median PFS was 4.3 months in arm B versus 3.5 months in arm A. The progression-free proportion after 15 months was 14.7% (CI 6.4-30.1%) in arm B versus 0% in arm A. The ORR was 30.6%/21.7%, CBR was 52.8%/43.5% and DRR was 13.9%/4.3% in arm B/A. The PFS advantage was observed for both PD-L1+ (n=27; HR 0.58) and PD-L1- subjects (n=31; HR 0.66). All five patients without progression after 15 months belonged to arm B, and three out of these patients were PD-L1 negative. Serious adverse events occurred for 48% in arm B and 29% in arm A (FAS). The most common immune related adverse events of any grade in arm B/A were hypothyroidism (10.0%/7.1 %), pneumonitis (10.0%/3.6%), hyperthyroidism (5.0%/7.1%) and rash (7.5%/3.6%). Further biomarker analyses and assessments of immunological changes during therapy are ongoing. Conclusions: The addition of atezolizumab to PLD and low-dose metronomic cyclophosphamide significantly improved PFS. A benefit was indicated also in patients with PD-L1 negative disease. The combination regimen was well tolerated with no new safety signals. Results from the ongoing analyses of consecutive tumor and blood samples will be important to assess the hypothesized immunological effects of the chemotherapy and to investigate biomarkers associated with the response to the combined treatment. Citation Format: Jon Amund Kyte, Andreas H. Røssevold, Nikolai K. Andresen, Christina Annette Bjerre, Bjørnar Gilje, Erik Hugger Jakobsen, Sunil Xavier Raj, Ragnhild Sørum Falk, Elin Borgen, Thea Jahr, Øystein Garred, Jon Lømo, Randi Margit Mathiesen, Bjørn Naume. PD11-11 Results from ALICE – Atezolizumab Combined with Immunogenic Chemotherapy in Patients with Metastatic Triple Negative Breast Cancer, a Randomized Phase IIb Trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD11-11.

PB2078: A RETROSPECTIVE ANALYSIS OF THE EFFICACY OF LOW-DOSE METRONOMIC CYCLOPHOSPHAMIDE FOR TREATMENT IN PATIENTS WITH LOW GRADE NON-HODGKIN LYMPHOMA

Background: Low-dose metronomic cyclophosphamide chemotherapy is an emerging strategy offering a potentially less toxic yet effective treatment modality. Aims: We evaluated the efficacy and safety of low-dose metronomic cyclophosphamide in patients with low grade non-Hodgkin lymphoma (NHL) by retrospectively reviewing the data. Methods: The patients received oral cyclophosphamide (50 mg per day) and/or oral methotrexate (2.5 mg twice weekly) until disease progression or unacceptable toxicity was noted. Results: Of the 36 patients, 17 (47.2%) were male, median age was 66.4 years (range, 37-91 years), and subtypes of NHL were mucosa associated lymphoid tissue lymphoma (55.6%), small lymphocytic lymphoma (13.9%), follicular lymphoma (11.1%), mantle cell lymphoma (8.3%), nodal marginal zone lymphoma (4.5%), splenic marginal zone lymphoma (2.8%), and lymphoplasmacytic lymphoma (2.8%). The stage I, II, III, IV were 38.9%, 13.9%, 11.1%, 36.1%, respectively and 55.6% of patients received this regimen as the first-line treatment, mainly due to frailty, refusal to standard chemotherapy. The overall best response rate (ORR) was 73.5% (12 complete responses, CRs and 13 partial responses, PRs), with 29.1 months of the median duration of response and the disease control rate was 88.2%. The median treatment duration was 8.8 months (range, 0.1-38.4 months); the median progression-free survival (PFS) was 43.5 months, and the median overall survival (OS) was not yet reached. Especially, the ORR in patients who were treated with metronomic cyclophosphamide as the first line treatment and as more than the second line treatment were 78.9% (10 CRs, 5 PRs) and 66.6% (2 CRs, 9 PRs), respectively. The median PFS were not reached in the first line cyclophosphamide treatment group and 26.5 months (range, 5.7-47.2 months) in the other group (p=0.110), and similarly, the median OS were not reached and 64.4 months (0-135.7 months) (p=0.058), respectively. The regimen was generally well tolerated, with small numbers of grade 3-4 toxicities; neutropenia (2%), anemia (3%), thrombocytopenia (3%), fatigue (4%), and anorexia (1%). Summary/Conclusion: We concluded that low-dose metronomic cyclophosphamide represents efficacious and well-tolerated treatment for low-grade NHL patients.

A Retrospective Analysis of the Efficacy of Low-Dose Metronomic Cyclophosphamide for Treatment in Patients with Low Grade Non-Hodgkin Lymphoma

BackgroundLow-dose metronomic cyclophosphamide chemotherapy is an emerging strategy offering a potentially less toxic yet effective treatment modality. We evaluated the efficacy and safety of low-dose metronomic cyclophosphamide in patients with low grade non-Hodgkin lymphoma (NHL) by retrospectively reviewing the data.MethodThe patients received oral cyclophosphamide (50 mg per day) and/or oral methotrexate (2.5 mg twice weekly) until disease progression or unacceptable toxicity was noted.ResultsOf the 36 patients, 17 (47.2%) were male, median age was 66.4 years (range, 37-91 years), and subtypes of NHL were mucosa associated lymphoid tissue lymphoma (55.6%), small lymphocytic lymphoma (13.9%), follicular lymphoma (11.1%), mantle cell lymphoma (8.3%), nodal marginal zone lymphoma (4.5%), splenic marginal zone lymphoma (2.8%), and lymphoplasmacytic lymphoma (2.8%). The stage I, II, III, IV were 38.9%, 13.9%, 11.1%, 36.1%, respectively and 55.6% of patients received this regimen as the first-line treatment, mainly due to frailty, refusal to standard chemotherapy.The overall best response rate (ORR) was 73.5% (12 complete responses, CRs and 13 partial responses, PRs), with 29.1 months of the median duration of response and the disease control rate was 88.2%. The median treatment duration was 8.8 months (range, 0.1-38.4 months); the median progression-free survival (PFS) was 43.5 months, and the median overall survival (OS) was not yet reached. Especially, the ORR in patients who were treated with metronomic cyclophosphamide as the first line treatment and as more than the second line treatment were 78.9% (10 CRs, 5 PRs) and 66.6% (2 CRs, 9 PRs), respectively. The median PFS were not reached in the first line cyclophosphamide treatment group and 26.5 months (range, 5.7-47.2 months) in the other group (p=0.110), and similarly, the median OS were not reached and 64.4 months (0-135.7 months) (p=0.058), respectively.The regimen was generally well tolerated, with small numbers of grade 3-4 toxicities; neutropenia (2%), anemia (3%), thrombocytopenia (3%), fatigue (4%), and anorexia (1%).ConclusionWe concluded that low-dose metronomic cyclophosphamide represents efficacious and well-tolerated treatment for low-grade NHL patients. DisclosuresNo relevant conflicts of interest to declare.

Theoretical premises of a "three in one" therapeutic approach to treat immunogenic and nonimmunogenic cancers: a narrative review.

ObjectiveWe describe experimental and theoretical premises of a powerful cancer therapy based on the combination of three approaches. These include (I) in situ vaccination (intratumoral injections of CpG oligonucleotides and anti-OX40 antibody); (II) chronometric or metronomic low-dose cyclophosphamide (CMLD CP)-based chemotherapy; (III) cancer stem cell-eradicating therapy referred to as Karanahan (from the Sanskrit kāraṇa [“source”] + han [“to kill”]).BackgroundIn murine models, the first two approaches are particularly potent in targeting immunogenic tumors for destruction. In situ vaccination activates a fully fledged anticancer immune response via an intricate network of ligand–receptor–cytokine interactions. CMLD CP-based chemotherapy primarily targets the suppressive tumor microenvironment and activates tumor-infiltrating effectors. In contrast, Karanahan technology, being aimed at replicative machinery of tumor cells (both stem-like and committed), does not depend on tumor immunogenicity. With this technology, mice engrafted with ascites and/or solid tumors can be successfully cured. There is a significant degree of mechanistic and therapeutic overlap between these three approaches. For instance, the similarities shared between in situ vaccination and Karanahan technology include the therapeutic procedure, the cell target [antigen-presenting cells (APC) and dendritic cells (DC)], and the use of DNA-based preparations (CpG and DNAmix). Features shared between CMLD CP-based chemotherapy and Karanahan technology are the timing and the dose of the cytostatic drug administration, which lead to tumor regression.MethodsThe following keywords were used to search PubMed for the latest research reporting successful eradication of transplantable cancers in animal models that relied on approaches distinct from those used in the Karanahan technology: eradication of malignancy, cure cancer, complete tumor regression, permanently eradicating advanced mouse tumor, metronomic chemotherapy, in situ vaccination, immunotherapy, and others.ConclusionWe hypothesize, therefore, that very potent anticancer activity can be achieved once these three therapeutic modalities are combined into a single approach. This multimodal approach is theoretically curative for any type of cancer that depends on the presence of tumor-inducing cancer stem cells, provided that the active therapeutic components are efficiently delivered into the tumor and the specific biological features of a given patient’s tumor are properly addressed. We expect this multimodal approach to be primarily applicable to late-stage or terminal cancer patients who have exhausted all treatment options as well as patients with inoperable tumors.

Trial to evaluate the immunogenicity and safety of a melanoma helper peptide vaccine plus incomplete Freund’s adjuvant, cyclophosphamide, and polyICLC (Mel63)

BackgroundPeptide vaccines designed to stimulate melanoma-reactive CD4+ T cells can induce T cell and antibody (Ab) responses, associated with enhanced overall survival. We hypothesized that adding toll-like receptor 3 agonist...

Adjuvant doxorubicin vs metronomic cyclophosphamide and meloxicam vs surgery alone for cats with mammary carcinomas: A retrospective study of 137 cases.

This study aims to evaluate the efficacy and side effects of low dose cyclophosphamide chemotherapy plus meloxicam as an adjuvant treatment, compared with high dose doxorubicin or surgery alone in cats with mammary carcinoma. Medical records of 228 female cats treated for mammary carcinoma between 2008 and 2018, were reviewed in eight veterinary institutions. Only cats with complete tumour staging and radical mastectomy were included in the study. One hundred and thirty-seven cats were divided into three treatment groups: group 1 (n=80) cats treated with surgery, group 2 (n=34) cats that had surgery and adjuvant treatment with doxorubicin, and group 3 (n=23) cats with surgery and adjuvant treatment with low dose metronomic cyclophosphamide and meloxicam. The study endpoints were disease free interval (DFI) and overall survival (OS). Toxicity was evaluated according to the VCOG-CTCAE criteria. The median DFI was 270, 226 and 372 days in groups 1, 2 and 3, respectively. The median OS was 338 (group 1), 421 (group 2) and 430 (group 3) days. The differences between groups were not significant (DFI P=.280 and OS P=.186). Toxicity was observed in 52.9% (n=18) of cats in group 2 and 39.1% (n=9) of cats in group 3, with mild to moderate intensity. Differences were not significant (P=.306). In conclusion, adjuvant chemotherapy treatment did not improve survival and the overall benefit remains unproven. Randomized prospective trials are necessary to clarify the effectiveness of adjuvant chemotherapy treatment for feline mammary carcinomas.

Metronomic low dose cyclophosphamide in combination with a DNA methyltransferase inhibitor limits tumor growth in murine triple negative breast cancer

Abstract Many breast cancers are treated with therapies that target herceptin, estrogen, or progesterone receptors; however, for triple-negative breast cancers (TNBC) that lack these receptors, treatment options are limited, and prognosis is often unfavorable. The goal of this study is to design a therapeutic intervention that can elicit an effective immune response against the tumor and instill immunological memory to eradicate primary and metastatic lesions. Guadecitabine (Guad) is a second-generation DNA methyltransferase inhibitor (DMNTi) that has been reported to have several antitumor properties such as increased antigenicity and depletion of myeloid-derived suppressor cells (MDSC’s). Cyclophosphamide is a FDA approved chemotherapy that has been shown, when given as a low-dose treatment, to selectively deplete regulatory T-cells (T-regs). Both MDSCs and T-regs suppress antitumor immunity. We hypothesize that the combination of Guad and Cyp will synergize and promote anticancer immunity through increased expression of de novo tumor antigens and depletion of MDSCs and T-regs in a low-dose setting. To test this hypothesis, BALB/c mice were challenged with murine TNBC 4T1 tumor cells and the 4T1-bearing mice were administered low-dose Guad and Cyp daily for ten consecutive days. This experiment showed a degree of synergy between Guad and Cyp with the dual therapy reducing tumor burden to a greater extent than either monotherapy.

Abstract B54: Single-cell analytics in claudin-low TNBC reveals immunostimulatory effects of low-dose metronomic cyclophosphamide treatment

Abstract Breast cancer is a heterogeneous disease. It can be classified into at least five subtypes: luminal A and B, normal breast like, Her2 positive, basal like, and claudin low. Among these, claudin-low tumors have relatively poor prognosis. These tumors are characterized by the low expression of cell-cell junction proteins along with an enrichment of EMT markers. They are more aggressive and the rate of response to primary chemotherapy is around 32%. Initial data have shown that murine p53 null claudin-low tumors are only sensitive to cyclophosphamide treatment. Cyclophosphamide (CTX) is a chemotherapy drug that has been used in lymphoma, leukemia, and some solid tumors. At low and continuous doses, it shows immunostimulatory properties. In this study we describe the implementation of a novel combination treatment for claudin-low TNBC as informed by combined scRNA-seq and V(D)J seq. Immune profiles of a murine claudin-low tumor model (T12) shows heavy infiltration by tumor-associated macrophages (TAMs) pretreatment. Initial data in T12 tumors also suggest that CTX induces CD4+ and CD8+ T-cell homing to the primary tumor. Wild-type Balb/c mice implanted with T12 tumors respond favorably to CTX treatment as compared to T cell-deficient NSG mice. We combined 5´ scRNA-seq with V(D)J seq to gain an insight into how immune cell subpopulations change during the course of treatment. Combining tSNE plots for untreated and treated tumors revealed the emergence of new transcriptionally distinct populations in the CTX treated group, which included six T cell subpopulations. Projection of T cells along pseudotime using Monocle3 revealed a shift from naive CD8+ and CD4+ T cells to a terminal effector CD8+ T-cell phenotype and CD4+ effector memory cells in treated tumors while untreated tumors have higher numbers of exhausted Tigit+ CD8+ T cells and Tregs. V(D)J analysis revealed higher numbers of unique TCRs in CTX-treated tumors and greater clonal expansion of T cells. However, we noted a persistence of TAMs in our model even after treatment as well as high recurrence rates upon cessation of treatment. We then examined markers specific to the TAM subsets in the treated and untreated tumors and observed that TAMs expressed high levels of Csf1r. A chow containing PLX3397(iCSF1R) was employed to inhibit CSF1R, a macrophage differentiation/recruitment factor. Combination treatment with CTX and the iCSF1R chow lead to long-term regression of T12 tumors. Rechallenging these mice resulted in much slower tumor growth, indicating the formation of T cell memory. scRNA-seq and V(D)J seq is being performed on these samples to identify the clonal dynamics of effector T cells that assist in this striking regression. We hypothesize that CTX treatment can sensitize T12 primary tumors to T cell-mediated apoptosis, and that TAMS can suppress T-cell function and promote chemoresistance. Furthermore, depleting these TAMs in combination with CTX treatment may lead to long-term durable regression of both the primary tumor and metastases. Citation Format: Swarnima Singh, Ying-Wooi Wan, Nigel Lee, Se-Jin Kim, Zhandong Liu, Charles M. Perou, Xiang Zhang, Jeffrey Rosen. Single-cell analytics in claudin-low TNBC reveals immunostimulatory effects of low-dose metronomic cyclophosphamide treatment [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr B54.

Low-dose Metronomic Cyclophosphamide Therapy as Postoperative Adjuvant Chemotherapy in 28 Dogs with Malignant Tumors

Low-dose Metronomic Cyclophosphamide Therapy as Postoperative Adjuvant Chemotherapy in 28 Dogs with Malignant Tumors

Low-dose metronomic cyclophosphamide complements the actions of an intratumoral C-class CpG TLR9 agonist to potentiate innate immunity and drive potent T cell-mediated anti-tumor responses.

The synthetic oligonucleotide SD-101 is a potent and specific agonist for toll-like receptor 9. Intratumoral injection of SD-101 induces significant anti-tumor immunity in preclinical and clinical studies, especially when combined with PD-1 blockade. To build upon this strategy, we studied the enhancement of SD-101 activities by combination with low-dose cyclophosphamide, a well-characterized agent with potentially complementary activities. In multiple mouse tumor models, we demonstrate substantial anti-tumor activity of the combination, compared to each single agent. Combination therapy generated CD8+ T cell dependent immunity leading to rejection of both non-injected and injected tumors and long-term survival, even in very large tumors. Mechanistic studies encompassing global gene expression changes and characterization of immune cell infiltrates show the rapid, sequential induction of innate and adaptive responses and identify discrete contributions of SD-101 and cyclophosphamide. Importantly, these changes were prominent in tumors not injected directly with SD-101. Combination treatment resulted in creation of a permissive environment for a systemic anti-tumor immune response, including a reduction of intratumoral regulatory T cells (Tregs) and an increase in “M1” versus “M2” tumor-associated macrophage (TAM) phenotypes. Additionally, we observed increased immunogenic cell death as well as antigen processing in response to combination treatment.

Safety and efficacy of low-dose metronomic cyclophosphamide plus vinorelbine in patients with metastatic breast cancer previously treated with anthracyclines and taxanes.

e13089Background: Metronomic chemotherapy has recently gained attention as a promising experimental strategy, involving alternative or complementary ways of using old and new anticancer chemotherap...

Adjuvant Doxorubicin with or without Metronomic Cyclophosphamide for Canine Splenic Hemangiosarcoma.

This retrospective study investigated the outcome of 33 dogs with splenic hemangiosarcoma treated with surgery followed by adjuvant dose-intensified doxorubicin (DOX) with or without low-dose metronomic cyclophosphamide (LDM-C) maintenance therapy. Among the 33 dogs, 18 dogs received LDM-C. Clinical stage was available for all dogs (5 stage I, 18 stage II, and 10 stage III). Nine dogs had macroscopic, and 24 dogs had microscopic disease at the start of DOX treatment. Median progression-free survival (PFS) and overall survival were 125 and 133 days, respectively. Clinical stage and tumor burden (microscopic versus macroscopic) at the start of chemotherapy was prognostic for PFS. No significant difference was observed in PFS or overall survival for the addition of LDM-C after a completed DOX protocol (P = .563 and P = .148, respectively). Based on the results of this retrospective study, the addition of LDM-C therapy as a maintenance regimen following a completed protocol of DOX adjuvant treatment of canine hemangiosarcoma may not improve outcome.

Effect of Modified Vaccinia Ankara–5T4 and Low-Dose Cyclophosphamide on Antitumor Immunity in Metastatic Colorectal Cancer

The success of immunotherapy with checkpoint inhibitors is not replicated in most cases of colorectal cancer; therefore, different strategies are urgently required. The oncofetal antigen 5T4 is expressed in more than 90% of cases of metastatic colorectal cancer (mCRC). Preliminary data using modified vaccinia Ankara-5T4 (MVA-5T4) in mCRC demonstrated that it safely induced serologic and T-cell responses. To determine whether antitumor immunity in mCRC could be increased using MVA-5T4, metronomic low-dose cyclophosphamide, or a combination of both treatments. In this randomized clinical trial, 55 patients with inoperable mCRC and prior stable disease after standard chemotherapy were enrolled at a single center and randomized to watch and wait (n = 9), cyclophosphamide treatment only (n = 9), MVA-5T4 only (n = 19), and a combination of MVA-5T4 and cyclophosphamide (n = 18). Patients were enrolled and treated from July 9, 2012, through February 8, 2016, and follow-up was completed on December 13, 2016. Data were analyzed based on intention to treat. Patients randomized to a cyclophosphamide group received 50 mg twice daily on treatment days 1 to 7 and 15 to 21. Patients randomized to a MVA-5T4 group received an intramuscular injection at a dose of 1 × 109 50% tissue culture infectious dose on treatment days 22, 36, 50, 64, 78, and 106. The predefined primary end point was the magnitude of anti-5T4 immune responses (5T4-specific T-cell and antibody levels) generated at treatment week 7. Secondary end points included analysis of the kinetics of anti-5T4 responses, progression-free survival (PFS), and overall survival (OS). Fifty-two patients (38 men and 14 women; mean [SD] age, 64.2 [10.1] years) were included in the study analysis. The 5T4-specific antibody immune responses were significantly increased in the MVA-5T4 (83.41 [36.09] relative units [RU]; P = .02) and combination treatment (65.81 [16.68] RU; P = .002) groups compared with no treatment (20.09 [7.20] RU). Cyclophosphamide depleted regulatory T cells in 24 of 27 patients receiving MVA-5T4, independently prolonging PFS (5.0 vs 2.5 months; hazard ratio [HR], 0.48; 95% CI, 0.21-1.11; P = .09). MVA-5T4 doubled baseline anti-5T4 responses in 16 of 35 patients, resulting in significantly prolonged PFS (5.6 vs 2.4 months; HR, 0.21; 95% CI, 0.09-0.47; P < .001) and OS (20.0 vs 10.3 months; HR, 0.32; 95% CI, 0.14-0.74; P = .008). No grade 3 or 4 adverse events were observed. This initial randomized clinical immunotherapy study demonstrates a significant survival benefit in mCRC. Prior depletion of regulatory T cells by cyclophosphamide did not increase immune responses generated by MVA-5T4 vaccination; however, cyclophosphamide and MVA-5T4 each independently induced beneficial antitumor immune responses, resulting in prolonged survival without toxic effects. Larger clinical trials are planned to further validate these data. isrctn.org Identifier: ISRCTN54669986.

Low-dose metronomic delivery of cyclophosphamide is less detrimental to granulosa cell viability, ovarian function, and fertility than maximum tolerated dose delivery in the mouse.

Chemotherapy can cause early menopause or infertility in women and have a profound negative impact on the quality of life of young female cancer survivors. Various factors are known to influence the risk of chemotherapy-induced ovarian failure, including the drug dose and treatment duration; however, the scheduling of dose administration has not yet been evaluated as an independent risk factor. We hypothesized that low-dose metronomic (LDM) chemotherapy scheduling would be less detrimental to ovarian function than the traditional maximum tolerated dose (MTD) strategy. In vitro, MTD cyclophosphamide exposure resulted in decreased proliferation and increased granulosa cell apoptosis, while cells treated with LDM cyclophosphamide were not different from untreated controls. Treatments of MTD cyclophosphamide induced high levels of follicle atresia and enhanced follicle recruitment in mice. In contrast, LDM delivery of an equivalent dose of cyclophosphamide reduced growing follicle numbers, but was not associated with higher levels of follicle atresia or recruitment. MTD cyclophosphamide induced significant vascular disruption and DNA damage in vivo, while LDM chemotherapy with equal cumulative amounts of cyclophosphamide was not different from controls. MTD chemotherapy also had a negative effect on mouse-fertility outcomes. Our findings suggest that LDM scheduling could potentially minimize the long-term effects of cyclophosphamide on female fertility by preventing follicle depletion from enhanced activation.

Whether low-dose metronomic oral cyclophosphamide improves the response to docetaxel in first-line treatment of non-triple-negative metastatic breast cancer

Oral metronomic chemotherapy may target tumor cells indirectly via antiangiogenic activity, restoration of anticancer immune response, or induction of tumor dormancy. We initiated the single-center, randomized, open-label, phase II study to determine whether the addition of metronomic cyclophosphamide to docetaxel (T) (w/o trastuzumab) improves overall response rate (ORR) as first-line treatment among patients with non-triple-negative metastatic breast cancer (MBC). Eligible patients with previously untreated non-triple-negative MBC were randomly assigned (1:1) to receive 3-weekly cycles of Metro-TC (T 75mg/m2, d1 plus oral cyclophosphamide 50 mg daily) or T alone. All patients received treatment until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint was ORR. Finally, 35 patients were randomized to Metro-TC group while 31 to T group. Median treatment cycles of T for both groups were 8. ORR was not improved by addition of metronomic cyclophosphamide to T (71.4% vs. 51.6%; P = 0.09). There was no statistically significant difference with regard to progression free survival (median 18.5 vs. 11.7 months; P = 0.07) or overall survival (median 33.7 vs. 33.6 months; P = 0.84) between the two group. Grade 3/4 adverse events (eg. neutropenia [100% vs. 100%], febrile neutropenia [29% vs. 29%], and neurotoxicity [6% vs. 3%]) were also comparable. There were no treatment-related deaths. We conclude that concomitant administration of metronomic cyclophosphamide and T does not appear to be a significantly active schedule for first-line treatment of non-triple-negative MBC.

Low dose metronomic cyclophosphamide, methotrexate (LDCM) and aspirin for patients with residual disease after neoadjuvant chemotherapy for stage II-III breast cancer.

e12040Background: The risk of recurrence for women who fail to achieve pathological complete response (pCR) to neoadjuvant chemotherapy is high (15-30% at 2 years). We investigated the effect of an...

A phase 2 clinical trial testing DPX-Survivac and metronomic low dose cyclophosphamide as immunotherapy for patients with recurrent diffuse large b-cell lymphoma.

e14578Background: Survivin is strongly expressed in tumors of about 60% of diffuse large B-cell lymphoma (DLBCL) patients. DPX-Survivac contains survivin HLA class I peptides in a novel formulation...

P2-2-55 - Study of low-dose metronomic cyclophosphamide plus vinorelbine in patients with metastatic breast cancer

P2-2-55 - Study of low-dose metronomic cyclophosphamide plus vinorelbine in patients with metastatic breast cancer

Abstract 2508: Multi-modal treatment with peptide vaccine, metronomic cyclophosphamide and anti-PD1 monoclonal antibody provides effective control of tumors in multiple models

Abstract Future cancer immunotherapies will combine multiple treatments to improve immune responses to cancer through synergistic, multi-modal mechanisms. In a phase I clinical trial, we found that metronomic cyclophosphamide (mCPA; 50 mg BID) enhanced the immunogenicity of a DepoVaxTM (DPX) based cancer vaccine (DPX-Survivac) in ovarian cancer patients. We emulated these results in preclinical transplantable tumor models which allowed us to study the underlying mechanisms of cyclophosphamide induced immune modulation and explore additional combinations to enhance the therapeutic effect. In syngeneic murine models for ovarian cancer (MOSE), melanoma (B16-F10) and HPV-induced cancer (C3), metronomic low dose cyclophosphamide (mCPA) on alternating weeks (20 mg/kg/day PO) in combination with a DPX peptide vaccine provided long-term control of established tumors. The addition of mCPA caused selective enrichment of antigen-specific CD8+ T cells resulting in increased immune responses detected by IFN-γ ELISPOT and in vivo cytotoxicity assay, as well as improved protection from tumors. Efficacy of the vaccine and mCPA combination was limited in mice bearing advanced tumors, yet antigen-specific CD8+ T cells could be detected infiltrating the tumor by flow cytometry along with increased expression of PD-1 by qPCR, suggesting that the combination therapy was able to generate strong cytotoxic T cell response but was still subject to tumor induced suppression within the tumor microenvironment. A triple combination therapy of mCPA, vaccine and anti-PD1 enabled the control and/or regression of established later-treated tumors which could not be achieved with a combination of mCPA and anti-PD1. To better understand the mechanism of the enhanced protection observed with the tri-therapy, mice were implanted with a mixture of C3 and B16 tumor cells and then treated with a vaccine against the C3 tumors alone, in combination with mCPA and anti-PD1. Splenocytes of mice treated with the tri-therapy produced IFN-γ ELISPOT responses towards both cell lines, suggesting epitope spreading. This effect could not be detected in tumor bearing mice treated with mCPA anti-PD1 without vaccine. We conclude that enhanced tumor control mediated by the tri-therapy is mediated by highly active, tumor-specific cytotoxic T lymphocytes produced by a strongly immunogenic vaccine, resulting in epitope spreading that can further facilitate tumor rejection or control. These results provide a rationale for clinical testing of checkpoint blockade therapy in combination with our highly immunogenic combination of mCPA and DPX-Survivac targeting the tumor associated antigen survivin. Citation Format: Genevieve Weir, Olga Hrytsenko, Marianne Stanford, Mohan Karkada, Neil Berinstein, Marc Mansour. Multi-modal treatment with peptide vaccine, metronomic cyclophosphamide and anti-PD1 monoclonal antibody provides effective control of tumors in multiple models. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2508. doi:10.1158/1538-7445.AM2015-2508

Abstract 3773: Identification of ALDH1A3 as a driver of resistance to both low-dose metronomic and conventional cyclophosphamide chemotherapy in prostate cancer

Abstract Prostate cancer (PCa) is the most common cancer in North American males. Conventional, maximum tolerated dose (MTD) chemotherapy with cyclophosphamide (CPA) has been used in the past for PCa treatment, but has been replaced by docetaxel. However, renewed interest in CPA is emerging given its frequent use in low-dose metronomic (LDM) chemotherapy regimens known for their antiangiogenic properties. While therapeutic resistance limits the clinical utility of both LDM and MTD CPA, such resistance appears to occur through at least partially distinct mechanisms. To investigate the molecular changes contributing to resistance formation, we have generated LDM and MTD CPA resistant PC-3 human prostate cancer cell variants (LCR and MCR, respectively), and corresponding control variants (NS), through in vivo passaging in mice. Using next-generation sequencing and gene expression analysis, we observed 453 differentially regulated genes in LCR vs NS, and 1141 genes in MCR vs NS. An intersecting set of 158 genes found to be differentially expressed in both resistant tumor cell lines was further characterized. The genes most up-regulated (including ALDH1A3, MAGEA2 and ELOVL2) and down-regulated (comprising FN1, IL8 and IGFBP3) were chosen for validation by qRT-PCR studies. We also undertook pathway analysis using the DAVID database and the Reactome FI Cytoscape Plugin. Collectively, our studies revealed that glycolysis/gluconeogenesis, biosynthesis of unsaturated fatty acids and activated drug metabolism may contribute to resistance to both LDM and MTD CPA. In addition, numerous chemokine signaling pathway-related genes were found to be downregulated. Current studies are focusing on the role of ALDH1A3 in LDM and MTD CPA resistance. ALDH1A3 is amongst the most differentially regulated genes found in our analysis, and it has been associated with chemotherapy resistance, ‘stemness’ and aggressive tumor behaviour. Despite different mechanisms of action, there are overlapping mechanisms of resistance to LDM and MTD CPA chemotherapy. If our studies confirm an essential role of ALDH13A in such resistance, this could be rapidly clinically translated by repurposing approved pharmacological ALDH inhibitors as anticancer agents. Citation Format: Van C. Hoang, Annabelle Chow, Amy Wong, Lavarnan Sivanathan, Urban Emmenegger. Identification of ALDH1A3 as a driver of resistance to both low-dose metronomic and conventional cyclophosphamide chemotherapy in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3773. doi:10.1158/1538-7445.AM2014-3773