Staphylococcus aureus induces drug resistance in cancer T cells in Sézary syndrome.

ABSTRACT: Patients with Sézary syndrome (SS), a leukemic variant of cutaneous T-cell lymphoma (CTCL), are prone to Staphylococcus aureus infections and have a poor prognosis due to treatment resistance. Here, we report that S aureus and staphylococcal enterotoxins (SE) induce drug resistance in malignant T cells against therapeutics commonly used in CTCL. Supernatant from patient-derived, SE-producing S aureus and recombinant SE significantly inhibit cell death induced by histone deacetylase (HDAC) inhibitor romidepsin in primary malignant T cells from patients with SS. Bacterial killing by engineered, bacteriophage-derived, S aureus-specific endolysin (XZ.700) abrogates the effect of S aureus supernatant. Similarly, mutations in major histocompatibility complex (MHC) class II binding sites of SE type A (SEA) and anti-SEA antibody block induction of resistance. Importantly, SE also triggers resistance to other HDAC inhibitors (vorinostat and resminostat) and chemotherapeutic drugs (doxorubicin and etoposide). Multimodal single-cell sequencing indicates T-cell receptor (TCR), NF-κB, and JAK/STAT signaling pathways (previously associated with drug resistance) as putative mediators of SE-induced drug resistance. In support, inhibition of TCR-signaling and Protein kinase C (upstream of NF-κB) counteracts SE-induced rescue from drug-induced cell death. Inversely, SE cannot rescue from cell death induced by the proteasome/NF-κB inhibitor bortezomib. Inhibition of JAK/STAT only blocks rescue in patients whose malignant T-cell survival is dependent on SE-induced cytokines, suggesting 2 distinct ways SE can induce drug resistance. In conclusion, we show that S aureus enterotoxins induce drug resistance in primary malignant T cells. These findings suggest that S aureus enterotoxins cause clinical treatment resistance in patients with SS, and antibacterial measures may improve the outcome of cancer-directed therapy in patients harboring S aureus.

Entinostat in patients with relapsed or refractory abdominal neuroendocrine tumors.

BACKGROUND: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare neoplasms with an increasing annual incidence and prevalence. Many are metastatic at presentation or recur following surgical resection and require systemic therapy, for which somatostatin analogs such as octreotide or lanreotide comprise typical first-line therapies. Nonetheless, treatment options remain limited. Epigenetic processes such as histone modifications have been implicated in malignant transformation and progression. In this study, we evaluated the anti-proliferative effects of a histone deacetylase (HDAC) inhibitor, entinostat, which was computationally predicted to show anti-cancer activity, as confirmed in in vitro and in vivo models of GEP-NETs. METHODS: This was a phase II study to evaluate the efficacy and safety of entinostat in patients with relapsed or refractory abdominal NETs. The primary objective was to estimate the objective response rate to entinostat. Additionally, with each patient as his/her own control we estimated the rates of tumor growth prior to enrollment on study and while receiving entinostat. Patients received 5 mg entinostat weekly until disease progression or intolerable toxicity. The dose could be changed to 10 mg biweekly for patients who did not experience grade ≥ 2 treatment-related adverse events (AEs) in cycle 1, but was primarily administered at the starting 5 mg weekly dose. RESULTS: The study enrolled only 5 patients due to early termination by the drug sponsor. The first patient that enrolled had advanced disease and died within days of enrollment before follow-up imaging due to a grade 5 AE unrelated to study treatment and was considered non-evaluable. Best RECIST response for the remaining 4 patients was stable disease (SD) with time on study of 154+, 243, 574, and 741 days. With each patient as his/her own control, rates of tumor growth on entinostat were markedly reduced with rates 17%, 20%, 33%, and 68% of the rates prior to enrollment on study. Toxicities possibly or definitely related to entinostat included grade 2/3 neutrophil count decrease [2/4 (50%)/ 2/4 (50%)], grade 3 hypophosphatemia [1/4, (25%)], grade 1/2 fatigue [1/4 (25%)/ 2/4 (50%)], and other self-limiting grade 1/2 AEs. CONCLUSION: In the treatment of relapsed or refractory abdominal NETs, entinostat 5 mg weekly led to prolonged SD and reduced the rate of tumor growth by 32% to 83% with an acceptable safety profile (ClinicalTrials.gov Identifier: NCT03211988).

Analysis of data from the PALOMA-3 trial confirms the efficacy of palbociclib and offers alternatives for novel assessment of clinical trials.

PURPOSE: There remains a need for novel therapies for patients with metastatic breast cancer (MBC). We explore the use of a novel biomarker of survival that could potentially expedite the testing of novel therapies. METHODS: We applied a tumor regression-growth model to radiographic measurement data from 393 women with MBC enrolled in PALOMA-3 examining efficacy of palbociclib in disease that had progressed on previous endocrine therapy. 261 and 132 women were randomized to fulvestrant plus palbociclib or placebo, respectively. We estimated rates of regression (d) and growth (g) of the sensitive and resistant fractions of tumors, respectively. We compared the median g of both arms. We examined the relationship between g and progression-free and overall survival (OS). RESULTS: As in other tumors, g is a biomarker of OS. In PALOMA-3, we found significant differences in g among patients with tumors sensitive to endocrine therapy but not amongst resistant tumors, emulating clinical trial results. Subgroup analysis found favorable g values in visceral metastases treated with palbociclib. Palbociclib efficacy demonstrated by slower g values was evident early in the trial, twelve weeks after the first 28 patients had been enrolled. CONCLUSION: Values of g, estimated using data collected while a patient is enrolled in a clinical trial is an excellent biomarker of OS. Our results correlate with the survival outcomes of PALOMA-3 and argue strongly for using g as a clinical trial endpoint to help inform go/no-go decisions, improve trial efficiency, and deliver novel therapies to patients sooner.

A Phase I Study of a Combination of Liposomal Irinotecan and Veliparib in Solid Tumors.

BACKGROUND: Multiple preclinical studies have shown cytotoxic synergy involving combinations of poly (ADP-ribose) polymerase (PARP) inhibitors and topoisomerase 1 (TOP1) inhibitors, but such combinations have proven too toxic in clinical trials. Liposomal irinotecan (nal-IRI) achieved similar intratumoral exposure with better antitumor activity than the conventional TOP1 inhibitor irinotecan in preclinical models. Tumor targeted delivery of TOP1 inhibitor using nal-IRI and an intermittent schedule of administration of PARP inhibitor may provide a tolerable combination. METHODS: A phase I study was performed to evaluate the safety and tolerability of escalating doses of nal-IRI and the PARP inhibitor veliparib in patients with solid tumors resistant to standard treatments. Nal-IRI was administered on days 1 and 15 and veliparib on days 5-12 and 19-25 in 28-day cycles. RESULTS: Eighteen patients were enrolled across 3 dose levels. Five patients encountered dose-limiting toxicities, including grade 3 diarrhea lasting more than 72 h in 3 patients and 1 patient each with grade 4 diarrhea and grade 3 hyponatremia. The most common grade 3 or 4 toxicities included diarrhea (50% of patients), nausea (16.6%), anorexia, and vomiting (11.1% each) (Table 1). There was no difference in frequencies of adverse events based on UGT1A1*28 status or prior opioid use (Table 1). CONCLUSION: The clinical trial was terminated due to high frequency of unacceptable gastrointestinal toxicities, which precluded dose escalation of veliparib in combination with nal-IRI (ClinicalTrials.gov Identifier: NCT02631733).

Tumor Growth Rate Informs Treatment Efficacy in Metastatic Pancreatic Adenocarcinoma: Application of a Growth and Regression Model to Pivotal Trial and Real-World Data.

BACKGROUND: Methods for screening agents earlier in development and strategies for conducting smaller randomized controlled trials (RCTs) are needed. METHODS: We retrospectively applied a tumor growth model to estimate the rates of growth of pancreatic cancer using radiographic tumor measurements or serum CA 19-9 values from 3033 patients with stages III-IV PDAC who were enrolled in 8 clinical trials or were included in 2 large real-world data sets. RESULTS: g correlated inversely with OS and was consistently lower in the experimental arms than in the control arms of RCTs. At the individual patient level, g was significantly faster for lesions metastatic to the liver relative to those localized to the pancreas. Regardless of regimen, g increased toward the end of therapy, often by over 3-fold. CONCLUSIONS: Growth rates of PDAC can be determined using radiographic tumor measurement and CA 19-9 values. g is inversely associated with OS and can differentiate therapies within the same trial and across trials. g can also be used to characterize changes in the behavior of an individual's PDAC, such as differences in the growth rate of lesions based on metastatic site, and the emergence of chemoresistance. We provide examples of how g can be used to benchmark phase II and III clinical data to a virtual reference arm to inform go/no go decisions and consider novel trial designs to optimize and accelerate drug development.

Long-term follow-up experience with adjuvant therapy after irreversible electroporation of locally advanced pancreatic cancer.

BACKGROUND: Irreversible electroporation (IRE) expands the surgical options for patients with unresectable pancreatic cancer. This study evaluated for differences in survival stratified by type of IRE and receipt of adjuvant chemotherapy. METHODS: Patients with locally advanced pancreatic cancer treated by IRE (2012-2020) were retrospectively included. Overall survival (OS) and recurrence-free survival (RFS) were compared by type of IRE (in situ for local tumor control or IRE of potentially positive margins with resection) and by receipt of adjuvant chemotherapy. RESULTS: Thirty-nine patients had IRE in situ, 61 had IRE for margin extension, and 19 received adjuvant chemotherapy. Most (97.00%) underwent induction chemotherapy. OS was 28.71 months (interquartile range [IQR] 19.17, 51.19) from diagnosis, with no difference by IRE type (hazard ratio [HR] 1.05 for margin extension [p = 0.85]) or adjuvant chemotherapy (HR 1.14 [p = 0.639]). RFS was 8.51 months (IQR 4.95, 20.17) with no difference by IRE type (HR 0.90 for margin extension [p = 0.694]) or adjuvant chemotherapy (HR 0.90 [p = 0.711]). CONCLUSION: These findings suggest that adjuvant therapy may have limited benefit for patients treated with induction chemotherapy followed by local control with IRE for unresectable pancreatic cancer. Further study of the duration and timing of systemic therapy is warranted to maximize benefit and limit toxicity.

Antibiotics and Imiquimod for Cutaneous T-Cell Lymphoma in Veterans: A Patient Population with Agent Orange Exposure.

LESSONS LEARNED: Staphylococcus aureus infection in cutaneous T-cell lymphoma (CTCL) is thought to contribute to disease progression; thus, adjunctive treatment with antibiotics warrants further investigation. This trial of antibiotic therapy followed by imiquimod in early stage CTCL was not completed because of difficulties with patient accrual. BACKGROUND: Cutaneous T-cell lymphoma (CTCL), a form of non-Hodgkin lymphoma, is a heterogeneous group of malignancies of mature memory T lymphocytes. It has an annual age-adjusted incidence of 7.5 per million persons in the U.S. population [1]. The etiology of CTCL is unknown, but epidemiological studies have reported potential associations with environmental and occupational factors, including Agent Orange exposure in Vietnam Veterans [2]. Both topical and systemic therapies have been identified as effective in CTCL; the choice of treatment is dependent on disease stage, with the overall goal of improving symptoms given the chronic and recurrent nature of the disease. Several studies have suggested that CTCL is exacerbated by the presence of Staphylococcus aureus in the skin and can be ameliorated by treatment with antibiotics [3]. METHODS: Our study was designed to assess the effects of antibiotics and imiquimod on early stage CTCL. Patients between the ages of 30-89 years with stage I and II CTCL were eligible for enrollment. They could not be receiving concurrent therapy, and the study design included a 14-day washout period after discontinuation of CTCL therapy. The washout period was followed by doxycycline 100 mg p.o. b.i.d. for 14 days and then two packets (250 mg per packet) of imiquimod 5% cream topically to the most clinically active lesions 3 days a week (Monday, Wednesday, and Friday) for 28 days. Skin lesions were measured using the modified Severity Weighted Assessment Tool (mSWAT). RESULTS: Our study enrolled only two patients with early stage CTCL because of difficulty locating patients with active CTCL able to discontinue all therapy. The two enrolled patients completed all therapy. One patient had a complete response after imiquimod, whereas the other patient had stable disease. CONCLUSION: Antibiotics and imiquimod have reported activity as single agents in CTCL; we did not enroll enough patients to assess value in the sequence of antibiotic therapy followed by imiquimod.

Prevention of Venous Thromboembolism in Pancreatic Cancer: Breaking Down a Complex Clinical Dilemma.

Venous thromboembolism (VTE) frequently occurs in patients with cancer, and particularly those with pancreatic ductal adenocarcinoma (PDAC). Therapeutic anticoagulation with either low-molecular-weight heparin or a direct oral anticoagulant is clearly beneficial in patients who develop a VTE. However, whether thromboprophylaxis improves patient outcomes remains unclear. Studies assessing this risk show a 10%-25% risk of VTE, with reduction to 5%-10% with thromboprophylaxis but no impact on survival. To aid in the risk stratification of patients, several tools have been developed to identify those at highest risk for a VTE event. However, the clinical application of these risk stratification models has been limited, and most patients, even those at the highest risk, will never have a VTE event. New oral anticoagulants have greatly improved the feasibility of prophylaxis but do show increased risk of bleeding in patients with the underlying gastrointestinal dysfunction frequently found in patients with pancreatic cancer. Recently, several completed clinical trials shed new light on this complicated risk versus benefit decision. Here, we present this recent evidence and discuss important considerations for the clinician in determining whether to initiate thromboprophylaxis in patients with PDAC. IMPLICATIONS FOR PRACTICE: Given the high risk of venous thromboembolism in patients with pancreatic adenocarcinoma (PDAC), whether to initiate prophylactic anticoagulation is a complex clinical decision. This review discusses recent evidence regarding the risk stratification and treatment options for thromboprophylaxis in patients with PDAC, with the goal of providing practicing clinicians with updates on recent developments in the field. This article also highlights important considerations for individualizing the treatment approach for a given patient given the lack of general consensus of uniform recommendations for this patient population.

Targeting mitochondrial hexokinases increases efficacy of histone deacetylase inhibitors in solid tumor models.

Hexokinase 1 and 2 have been shown to inhibit Bak- and Bax-mediated apoptosis, leading us to combine the histone deacetylase inhibitor romidepsin with clotrimazole or bifonazole, two compounds that reportedly decrease mitochondrial localization of hexokinases. Cancer cell lines derived from breast, kidney, lung, colon or ovarian cancers were treated with a short-term exposure to 25 ng/ml romidepsin combined with either clotrimazole or bifonazole. The combination of romidepsin with 25 µM clotrimazole or bifonazole resulted in increased annexin staining compared to cells treated with any of the drugs alone. Cell death was caspase-mediated, as the pan-caspase inhibitor Q-VD-OPh was found to inhibit apoptosis induced by the combination. A549 lung cancer cells or HCT-116 cells deficient in Bak and Bax were also resistant to apoptosis with the combination implicating the intrinsic apoptotic pathway. We found that a 24 h treatment with clotrimazole or bifonazole decreased total hexokinase 2 expression, resulting in a 76% or 60% decrease, respectively, of mitochondrial expression of hexokinase 2. Mitochondrial hexokinase 1 levels increased 2-fold or less. Our work suggests that the combination of a short-term romidepsin treatment with bifonazole or clotrimazole leads to increased apoptosis, most likely due to decreased mitochondrial expression of hexokinase 2.

Cisplatin versus cetuximab with definitive concurrent radiotherapy for head and neck squamous cell carcinoma: An analysis of Veterans Health Affairs data.

BACKGROUND: The addition of cisplatin or cetuximab to radiation therapy (RT) improves outcomes in comparison with RT alone in the nonoperative management of head and neck squamous cell carcinoma (HNSCC), but limited data exist for comparing these approaches. Using Veterans Health Affairs data, this study compared the outcomes of patients treated with RT plus cisplatin or cetuximab. METHODS: Patients with stage III to IVb HNSCC who had been treated nonsurgically with RT and cisplatin or cetuximab from 2000 to 2016 within the Veterans Health Affairs system were identified. Patients were analyzed by the drug used in the first treatment cycle (intent to treat). Overall survival (OS) was compared by treatment group with Cox regression models, and propensity score (PS) methods were used to account for a treatment allocation bias. The risk of toxicities was determined, with logistic regression models fit into propensity-matched cohorts. RESULTS: A total of 4520 patients were included in the analysis with a median follow-up of 3 years: 83% received cisplatin. Cisplatin patients were younger (P < .001) and had fewer comorbidities (P < .001). In an unmatched analysis, cetuximab was associated with inferior OS (P < .001). After PS matching, cetuximab treatment remained statistically significantly associated with inferior OS (1.7 vs 4.1 years; hazard ratio, 1.61; 95% confidence interval, 1.44-1.79; P < .001). These differences remained significant across all primary HNSCC subsites and in comparison with low- and high-dose cisplatin. CONCLUSIONS: Cetuximab with RT yields inferior OS in comparison with cisplatin for the nonoperative management of stage III to IVb HNSCC. According to this study, cisplatin may be the most appropriate partner for RT in this setting.

Publish or Perish v2.

Communication of clinical trial outcomes is important, but the results of many clinical trials are never published. If we do not publish the results of clinical trials, the lessons learned from those trials will perish. The Oncologist offers a powerful solution through the Clinical Trial Results publishing platform, which uses an established template for authors to easily build a manuscript by simply providing the essential trial data. Through it, every patient's legacy of clinical trial enrollment can matter.

PD-1 Pandemonium at the American Association for Cancer Research Annual Meeting.

This editorial describes the results of discussions between the U.S. FDA Oncology Center of Excellence and members of six pharmaceutical companies­a forum aptly named PD­1 Pandemonium­regarding development and regulatory approvals of immune checkpoint inhibitors.

Conflict of Interest: An Ethical Firestorm with Consequences for Cancer Research.

As the challenge of proper reporting of potential financial conflicts of interest is once again brought into the national spotlight, this editorial considers the recent events, expands on current systems for enforcing accurate reporting of financial disclosures, and considers ways to move forward.