Neoadjuvant-Adjuvant or Adjuvant-Only Pembrolizumab in Advanced Melanoma.

BACKGROUND: Whether pembrolizumab given both before surgery (neoadjuvant therapy) and after surgery (adjuvant therapy), as compared with pembrolizumab given as adjuvant therapy alone, would increase event-free survival among patients with resectable stage III or IV melanoma is unknown. METHODS: In a phase 2 trial, we randomly assigned patients with clinically detectable, measurable stage IIIB to IVC melanoma that was amenable to surgical resection to three doses of neoadjuvant pembrolizumab, surgery, and 15 doses of adjuvant pembrolizumab (neoadjuvant-adjuvant group) or to surgery followed by pembrolizumab (200 mg intravenously every 3 weeks for a total of 18 doses) for approximately 1 year or until disease recurred or unacceptable toxic effects developed (adjuvant-only group). The primary end point was event-free survival in the intention-to-treat population. Events were defined as disease progression or toxic effects that precluded surgery; the inability to resect all gross disease; disease progression, surgical complications, or toxic effects of treatment that precluded the initiation of adjuvant therapy within 84 days after surgery; recurrence of melanoma after surgery; or death from any cause. Safety was also evaluated. RESULTS: At a median follow-up of 14.7 months, the neoadjuvant-adjuvant group (154 patients) had significantly longer event-free survival than the adjuvant-only group (159 patients) (P = 0.004 by the log-rank test). In a landmark analysis, event-free survival at 2 years was 72% (95% confidence interval [CI], 64 to 80) in the neoadjuvant-adjuvant group and 49% (95% CI, 41 to 59) in the adjuvant-only group. The percentage of patients with treatment-related adverse events of grades 3 or higher during therapy was 12% in the neoadjuvant-adjuvant group and 14% in the adjuvant-only group. CONCLUSIONS: Among patients with resectable stage III or IV melanoma, event-free survival was significantly longer among those who received pembrolizumab both before and after surgery than among those who received adjuvant pembrolizumab alone. No new toxic effects were identified. (Funded by the National Cancer Institute and Merck Sharp and Dohme; S1801 ClinicalTrials.gov number, NCT03698019.).

Autophagy as a therapeutic mechanism to kill drug-resistant cancer cells.

Herein we discuss multiple pre-clinical projects developed by our group that have been translated into patients at Massey Cancer Center. Our work has used multi-kinase inhibitors, for example, sorafenib, regorafenib and neratinib, and combined with additional agents, for example, histone deacetylase inhibitors, the thymidylate synthase inhibitor pemetrexed, and PDE5 inhibitors. In broad-brush terms, our experience has been that these drug combinations enhance signaling by ATM-AMPK-ULK-1 and decrease signaling from growth factor receptors and RAS proteins, thereby lowering the activities of the intracellular signaling kinase ERK1/2, AKT, mTOR and p70 S6K . This collectively results in reduced protein synthesis and the induction of an endoplasmic reticulum stress response alongside autophagosome formation and autophagic flux. The rupture of autolysosomes, releasing proteases such as cathepsin B into the cytosol results in the cleavage and activation of the toxic BH3 domain protein BID which cooperates with BAX, BAK and BIM to cause mitochondrial dysfunction, leading to the release of cytochrome c and AIF, which then execute the tumor cell. For each of our two-drug combinations, we then performed additional laboratory-based studies to define the development of evolutionary resistance mechanisms, with the long-term concept of performing new three-drug clinical trials to prolong therapeutic efficacy and disease control.

A phase 1 study of regorafenib and sildenafil in adults with advanced solid tumors.

The purpose of this study is to establish the recommended phase 2 dose for regorafenib in combination with sildenafil for patients with advanced solid tumors. Secondary outcomes included identification of antitumor effects of regorafenib and sildenafil, toxicity of the combination, determination of PDE5 expression in tumor samples, and the impact of sildenafil on the pharmacokinetics of regorafenib. This study was a phase 1, open-label single-arm dose-escalation trial using a 3 + 3 design. Additional patients were enrolled at the maximum tolerated dose (MTD) until a total of 12 patients were treated at the MTD. A total of 29 patients were treated in this study. The median duration of treatment was 8 weeks. The recommended phase 2 doses determined in this study are regorafenib 160 mg daily with sildenafil 100 mg daily. The most common toxicities included palmar-plantar erythrodysesthesia syndrome (20 patients, 69%) and hypophosphatemia (18 patients, 62%). Two patients (7%) experienced grade 4 lipase increase. Objective responses were not observed; however, 14 patients (48%) had a period of stable disease during the study. Stable disease for up to 12 months was observed in patients with ovarian cancer as well as up to 20 months for a patient with cervical cancer. The combination of regorafenib and sildenafil at the recommended phase 2 dose is safe and generally well tolerated. Disease control in patients with gynecologic malignancies was especially encouraging. Further evaluation of the combination of regorafenib and sildenafil in gynecologic malignancies is warranted. Clinical Trial Registration Number: NCT02466802.

Pembrolizumab versus placebo as adjuvant therapy in completely resected stage IIB or IIC melanoma (KEYNOTE-716): a randomised, double-blind, phase 3 trial.

BACKGROUND: Pembrolizumab prolongs progression-free and overall survival among patients with advanced melanoma and recurrence-free survival in resected stage III disease. KEYNOTE-716 assessed pembrolizumab as adjuvant therapy in patients with completely resected, high-risk, stage II melanoma. We report results from the planned first and second interim analyses for recurrence-free survival. METHODS: In this double-blind, randomised, placebo-controlled phase 3 study, involving 160 academic medical centres and hospitals in 16 countries (Australia, Belgium, Brazil, Canada, Chile, France, Germany, Israel, Italy, Japan, Poland, South Africa, Spain, Switzerland, the UK, and the USA), patients aged 12 years or older with newly diagnosed, completely resected stage IIB or IIC melanoma (TNM stage T3b or T4 with a negative sentinel lymph node biopsy) were recruited. Eligible patients were randomly assigned (1:1), in blocks of four and stratified by T-category (3b, 4a, and 4b) and paediatric status (age 12-17 years vs ≥18 years), using an interactive response technology system to intravenous pembrolizumab 200 mg (2 mg/kg in paediatric patients) or placebo every 3 weeks for 17 cycles or until disease recurrence or unacceptable toxicity. All patients, clinical investigators, and analysts were masked to treatment assignment. The primary endpoint was investigator-assessed recurrence-free survival (defined as time from randomisation to recurrence or death) in the intention-to-treat (ITT) population (ie, all patients randomly assigned to treatment). The primary endpoint was met if recurrence-free survival was significantly improved for pembrolizumab versus placebo at either the first interim analysis (after approximately 128 patients had events) or second interim analysis (after 179 patients had events) under multiplicity control. Safety was assessed in all patients randomly assigned to treatment who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03553836, and is closed to accrual. FINDINGS: Between Sept 23, 2018, and Nov 4, 2020, 1182 patients were screened, of whom 976 were randomly assigned to pembrolizumab (n=487) or placebo (n=489; ITT population). The median age was 61 years (IQR 52-69) and 387 (40%) patients were female and 589 (60%) were male. 874 (90%) of 976 patients were White and 799 (82%) were not Hispanic or Latino. 483 (99%) of 487 patients in the pembrolizumab group and 486 (99%) of 489 in the placebo group received assigned treatment. At the first interim analysis (data cutoff on Dec 4, 2020; median follow-up of 14·4 months [IQR 10·2-18·7] in the pembrolizumab group and 14·3 months [10·1-18·7] in the placebo group), 54 (11%) of 487 patients in the pembrolizumab group and 82 (17%) of 489 in the placebo group had a first recurrence of disease or died (hazard ratio [HR] 0·65 [95% CI 0·46-0·92]; p=0·0066). At the second interim analysis (data cutoff on June 21, 2021; median follow-up of 20·9 months [16·7-25·3] in the pembrolizumab group and 20·9 months [16·6-25·3] in the placebo group), 72 (15%) patients in the pembrolizumab group and 115 (24%) in the placebo group had a first recurrence or died (HR 0·61 [95% CI 0·45-0·82]). Median recurrence-free survival was not reached in either group at either assessment timepoint. At the first interim analysis, grade 3-4 treatment-related adverse events occurred in 78 (16%) of 483 patients in the pembrolizumab groups versus 21 (4%) of 486 in the placebo group. At the first interim analysis, four patients died from an adverse event, all in the placebo group (one each due to pneumonia, COVID-19-related pneumonia, suicide, and recurrent cancer), and at the second interim analysis, one additional patient, who was in the pembrolizumab group, died from an adverse event (COVID-19-related pneumonia). No deaths due to study treatment occurred. INTERPRETATION: Pembrolizumab as adjuvant therapy for up to approximately 1 year for stage IIB or IIC melanoma resulted in a significant reduction in the risk of disease recurrence or death versus placebo, with a manageable safety profile. FUNDING: Merck Sharp & Dohme, a subsidiary of Merck & Co, Kenilworth, NJ, USA.

Cellular responses after (neratinib plus pemetrexed) exposure in NSCLC cells.

We previously demonstrated that neratinib interacted with pemetrexed to kill non-small cell lung cancer (NSCLC) cells. From developing other drug combinations, we observed that several days following exposure, cells activated survival mechanisms to counteract drug toxicity. The present studies attempted to define mechanisms that evolve to reduce the efficacy of neratinib and pemetrexed. Neratinib and pemetrexed synergized to kill NSCLC cells expressing wild-type RAS proteins, mutant KRAS (G12S; Q61H; G12A and G12C) or mutant NRAS (Q61K) or mutant ERBB1 (L858R; L858R T790M and exon 19 deletion). Neratinib and pemetrexed interacted in a greater than additive fashion to kill after 24 h, and after a further 24 h culture in the absence of drugs. Mutant KRAS G12V was more cytoprotective than either activated MEK1 or activated AKT. Knockdown of mutant KRAS reduced drug combination killing at the 48 h timepoint. Despite culture for 24 h in the absence of the drugs, the expression and activities of ERBB1, ERBB2 and ERBB4 remained significantly lower as did the activities of mammalian target of rapamycin (mTOR) C1 and mTORC2. The drug combination reduced KRAS and NRAS levels for 24 h, however, in the absence of the drugs, RAS levels had normalized by 48 h. Expression of Beclin1 and ATG5 remained elevated and of MCL1 and BCL-XL lower. No evolutionary activations of survival signaling by ERBB3, c-KIT, c-MET or PDGFRß or in intracellular signaling pathways were observed. These findings argue against the development of 'early' resistance mechanisms after neratinib and pemetrexed exposure. Future studies will be required to understand how NSCLC cells become resistant to neratinib and pemetrexed.

The development of multi-kinase inhibitors as pancreatic cancer therapeutics.

Pancreatic cancer is an almost incurable malignancy whose incidence has increased over the past 30 years. Instead of pursuing the development of modalities utilizing 'traditional' cytotoxic chemotherapeutic agents, we have explored the possibilities of developing novel multi-kinase inhibitor drug combinations to kill this tumor type. Several approaches using the multi-kinase inhibitors sorafenib, regorafenib, and neratinib have been safely translated from the bench to the bedside, with objective anti-tumor responses. This review will discuss our prior preclinical and clinical studies and discuss future clinical opportunities in this disease.

(Curcumin+sildenafil) enhances the efficacy of 5FU and anti-PD1 therapies in vivo.

We have extended our analyses of (curcumin+sildenafil) biology. The drug combination caused vascularization and degradation of mutant K-RAS that correlated with reduced phosphorylation of ERK1/2, AKT T308, mTORC1, mTORC2, ULK1 S757, STAT3, STAT5, and NFκB and increased phosphorylation of eIF2α, ATM, AMPKα, ULK1 S317; all concomitant with elevated ATG13 S318 phosphorylation and autophagosome formation. Prior studies with drug combinations utilizing sildenafil have delineated an ATM-AMPK-ULK1 S317 pathway and an AKT-mTOR-ULK1 S757 pathway as modules which control ATG S318 phosphorylation and autophagosome formation. The knockdown of PKG reduced cell killing as well as reducing drug-enhanced phosphorylation of ATM, AMPKα, and ATG13. In the absence of PKG, no significant increase in ULK1 S317 phosphorylation was observed. In a Beclin1-dependent fashion, the drug combination reduced the expression of multiple histone deacetylase (HDAC) proteins, including HDAC2 and HDAC3. Molecular knockdown of HDAC2, HDAC3, and especially (HDAC2+HDAC3) significantly reduced the expression of PD-L1 and elevated expression of Class I human major histocompatibility complex. In vivo, (curcumin+sildenafil) enhanced the efficacy of 5-flurouracil against CT26 colorectal tumors. Prior exposure of established CT26 tumors to (curcumin+sildenafil) significantly enhanced the efficacy of a subsequently administered anti-PD-1 antibody. Collectively our data argue that (curcumin+sildenafil) has the potential in several settings to be an efficacious neoadjuvant therapy for colon cancer.

Neratinib degrades MST4 via autophagy that reduces membrane stiffness and is essential for the inactivation of PI3K, ERK1/2, and YAP/TAZ signaling.

The irreversible ERBB1/2/4 inhibitor neratinib causes plasma membrane-associated K-RAS to mislocalize into intracellular vesicles liminal to the plasma membrane; this effect is enhanced by HDAC inhibitors and is now a Phase I trial (NCT03919292). The combination of neratinib and HDAC inhibitors killed pancreatic cancer and lymphoma T cells. Neratinib plus HDAC inhibitor exposure was as efficacious as (paclitaxel+gemcitabine) at killing pancreatic cancer cells. Neratinib reduced the phosphorylation of PAK1, Merlin, LATS1/2, AKT, mTOR, p70 S6K, and ERK1/2 which required expression of Rubicon, Beclin1, and Merlin. Neratinib altered pancreatic tumor cell morphology which was associated with MST4 degradation reduced Ezrin phosphorylation and enhanced phosphorylation of MAP4K4 and LATS1/2. Knockdown of the MAP4K4 activator and sensor of membrane rigidity RAP2A reduced basal LATS1/2 and YAP phosphorylation but did not prevent neratinib from stimulating LATS1/2 or YAP phosphorylation. Beclin1 knockdown prevented MST4 degradation, Ezrin dephosphorylation and neratinib-induced alterations in tumor cell morphology. Our findings demonstrate that neratinib enhances LATS1/2 phosphorylation independently of RAP2A/MAP4K4 and that MST4 degradation and Ezrin dephosphorylation may represent a universal trigger for the biological actions of neratinib.

Considering adjuvant therapy for stage II melanoma.

Melanoma is among the few cancers that demonstrate an increasing incidence over time. Simultaneously, this trend has been marked by an epidemiologic shift to earlier stage at diagnosis. Before 2011, treatment options were limited for patients with metastatic disease, and the median overall survival was less than 1 year. Since then, the field of melanoma therapeutics has undergone major changes. The use of anti-CTLA-4 and anti-PD1 immune checkpoint inhibitors and combination BRAF/MEK inhibitors for patients with BRAF V600 mutations has significantly extended survival and allowed some patients to remain in durable disease remission off therapy. It has now been confirmed that these classes of agents have a benefit for patients with stage III melanoma after surgical resection, and anti-PD1 and BRAF/MEK inhibitors are standards of care in this setting. Some patients with stage II disease (lymph node-negative; American Joint Committee on Cancer stage IIB and IIC) have worse melanoma-specific survival relative to some patients with stage III disease. Given these results, expanding the population of patients who are considered for adjuvant therapy to include those with stage II melanoma has become a priority, and randomized phase 3 clinical trials are underway. Moving into the future, the validation of patient risk-stratification and treatment-benefit prediction models will be important to improve the number needed to treat and limit exposure to toxicity in the large population of patients with early stage melanoma.

A multi-institutional phase 2 trial of regorafenib in refractory advanced biliary tract cancer.

BACKGROUND: Regorafenib is an oral multikinase inhibitor targeting angiogenesis, oncogenesis, and cancer proliferation/metastasis. This study evaluated the efficacy of regorafenib in refractory biliary tract cancer (BTC) in a multi-institutional phase 2 study. METHODS: Patients with BTC who progressed on at least 1 line of systemic therapy received regorafenib at 160 mg daily for 21 days on and 7 days off. The primary endpoint was 6-month overall survival (OS), and the secondary endpoints were median OS, progression-free survival (PFS), and objective response rates. Pretreatment plasma was collected for cytokine evaluation. RESULTS: A total of 39 patients were enrolled, and 33 were evaluable for efficacy. The median PFS and OS were 3.7 and 5.4 months, respectively, with survival rates of 46.2% at 6 months, 35.9% at 12 months, and 25.6% at 18 months for the intention-to-treat population. For the 33 evaluable patients who received regorafenib for at least 3 weeks, the median PFS and OS were 3.9 and 6.7 months, respectively, with survival rates of 51.5% at 6 months, 39.4% at 12 months, and 27.3% at 18 months. The objective response rate was 9.1%, and the disease control rate was 63.6%. Twenty-eight patients (71.8%) experienced grade 3/4 adverse events. Among the 23 cytokines analyzed, elevated baseline vascular endothelial growth factor D (VEGF-D) was associated with shorter PFS, whereas elevated baseline interleukin 6 (IL-6) and glycoprotein 130 (GP130) were associated with shorter OS. CONCLUSIONS: Regorafenib demonstrated modest clinical efficacy in heavily pretreated patients with BTC. Further exploration of biomarkers is warranted to identify a group of patients with BTC who may benefit from regorafenib.

KEYNOTE-716: Phase III study of adjuvant pembrolizumab versus placebo in resected high-risk stage II melanoma.

Patients with high-risk stage II melanoma are at significant risk for recurrence after surgical resection. Adjuvant treatment options to lower the risk for distant metastases are limited. Although adjuvant IFN-α2b is associated with improved relapse-free survival in patients with high-risk melanoma, toxicity and limited overall survival benefits limit its use. Adjuvant treatment with the PD-1 inhibitor pembrolizumab significantly improved recurrence-free survival, compared with placebo, in patients with resected stage III melanoma in the Phase III KEYNOTE-054 trial; efficacy in patients with stage II disease has not been established. This article describes the design and rationale of KEYNOTE-716 (NCT03553836), a two-part, randomized, placebo-controlled, multicenter Phase III study of adjuvant pembrolizumab in patients with surgically resected high-risk stage II melanoma. Clinical trial registry & ID: ClinicalTrials.gov, NCT03553836.

Neratinib augments the lethality of [regorafenib + sildenafil].

Regorafenib is approved for the treatment of colorectal cancer and hepatocellular carcinoma. In the trial NCT02466802, we have discovered that regorafenib can be safely combined with the phosphodiesterase 5 inhibitor sildenafil in advanced solid tumor patients. The present studies determined whether the approved ERBB1/2/4 and RAS downregulating drug neratinib, could enhance the lethality of [regorafenib + sildenafil]. Neratinib enhanced [regorafenib + sildenafil] lethality in a greater than additive fashion in colon cancer cells. The drug combination reduced the expression of mutant K-RAS and of multiple histone deacetylase (HDAC) proteins that required autophagosome formation. It caused green fluorescent protein or red fluorescent protein-tagged forms of K-RAS V12 to localize into large intracellular vesicles. Compared with [regorafenib + sildenafil], the three-drug combination caused greater and more prolonged activation of the ATM-AMPK-ULK-1 pathway and caused a greater suppression and prolonged inactivation of mammalian target of rapamycin, AKT, and p70 S6K. Approximately 70% of enhanced lethality caused by neratinib required ataxia-telangiectasia-mutated (ATM)-AMP-dependent protein kinase (AMPK) signaling whereas knockdown of Beclin1, ATG5, FADD, and CD95 completely prevented the elevated killing effect. Exposure of cells to [regorafenib + sildenafil] reduced the expression of the checkpoint immunotherapy biomarkers programmed death-ligand 1, ornithine decarboxylase, and indoleamine 2,3-dioxygenase-1 and increased the expression of major histocompatibility complex A (MHCA), which also required autophagosome formation. Knockdown of specific HDAC proteins recapitulated the effects observed using chemical agents. In vivo, using mouse cancer models, neratinib significantly enhanced the antitumor efficacy of [regorafenib + sildenafil]. Our data support performing a new three drug Phase I trial combining regorafenib, sildenafil, and neratinib.

BMI, irAE, and gene expression signatures associate with resistance to immune-checkpoint inhibition and outcomes in renal cell carcinoma.

BACKGROUND: Clinical variables may correlate with lack of response to treatment (primary resistance) or clinical benefit in patients with clear cell renal cell carcinoma (ccRCC) treated with anti-programmed death 1/ligand one antibodies. METHODS: In this multi-institutional collaboration, clinical characteristics of patients with primary resistance (defined as progression on initial computed tomography scan) were compared to patients with clinical benefit using Two sample t-test and Chi-square test (or Fisher's Exact test). The Kaplan-Meier method was used to estimate the distribution of progression-free survival (PFS) and overall survival (OS) in all patients and the subsets of patients with clinical benefit or primary resistance. Cox's regression model was used to evaluate the correlation between survival endpoints and variables of interest. To explore clinical factors in a larger, independent patient sample, The Cancer Genome Atlas (TCGA) was analyzed. RNAseq gene expression data as well as demographic and clinical information were downloaded for primary tumors of 517 patients included within TCGA-ccRCC. RESULTS: Of 90 patients, 38 (42.2%) had primary resistance and 52 (57.8%) had clinical benefit. Compared with the cohort of patients with initial benefit, primary resistance was more likely to occur in patients with worse ECOG performance status (p = 0.03), earlier stage at diagnosis (p = 0.04), had no prior nephrectomy (p = 0.04) and no immune-related adverse events (irAE) (p = 0.02). In patients with primary resistance, improved OS was significantly correlated with lower International Metastatic RCC Database Consortium risk score (p = 0.02) and lower neutrophil:lymphocyte ratio (p = 0.04). In patients with clinical benefit, improved PFS was significantly associated with increased BMI (p = 0.007) and irAE occurrence (p = 0.02) while improved OS was significantly correlated with overweight BMI (BMI 25-30; p = 0.03) and no brain metastasis (p = 0.005). The cohort TCGA-ccRCC was examined for the correlations between gene expression patterns, clinical factors, and survival outcomes observing associations of T-cell inflammation and angiogenesis signatures with histologic grade, pathologic stage and OS. CONCLUSIONS: Clinical characteristics including performance status, BMI and occurrence of an irAE associate with outcomes in patients with ccRCC treated with immunotherapy. The inverse association of angiogenesis gene signature with ccRCC histologic grade highlight opportunities for adjuvant combination VEGFR2 tyrosine kinase inhibitor and immune-checkpoint inhibition.

Prognostic Value of Low Tumor Burden in Patients With Melanoma.

The therapeutic landscape for cutaneous melanoma has dramatically advanced in the last several years with the development, validation, and approval by the US Food and Drug Administration of several new therapies that have proven effective in treating metastatic disease. Considerable effort has been put into identifying prognostic and predictive markers of therapeutic response to better delineate the patient populations most likely to benefit from treatment. Baseline tumor burden has been described as a common clinical factor associated with treatment response: lower tumor burden at the time of therapeutic intervention is associated with improved responses and survival outcomes on several therapies. Some therapies have shown efficacy as adjuvant interventions in patients with subclinical disease following definitive treatment, further supporting their role in patients with minimal tumor burden. The increasing evidence that patients with lower tumor burden may be the ones who derive maximal benefit from several melanoma-directed therapies points toward the critical need for risk-tailored surveillance to permit early identification of melanoma metastasis in patients at high risk for recurrence.

Sorafenib/regorafenib and lapatinib interact to kill CNS tumor cells.

The present studies were to determine whether the multi-kinase inhibitor sorafenib or its derivative regorafenib interacted with the ERBB1/ERBB2 inhibitor lapatinib to kill CNS tumor cells. In multiple CNS tumor cell types sorafenib and lapatinib interacted in a greater than additive fashion to cause tumor cell death. Tumor cells lacking PTEN, and anoikis or lapatinib resistant cells were as sensitive to the drug combination as cells expressing PTEN or parental cells, respectively. Similar data were obtained using regorafenib. Treatment of brain cancer cells with [sorafenib + lapatinib] enhanced radiation toxicity. The drug combination increased the numbers of LC3-GFP vesicles; this correlated with a reduction in endogenous LC3II, and p62 and LAMP2 degradation. Knock down of Beclin1 or ATG5 significantly suppressed drug combination lethality. Expression of c-FLIP-s, BCL-XL, or dominant negative caspase 9 reduced drug combination toxicity; knock down of FADD or CD95 was protective. Expression of both activated AKT and activated MEK1 or activated mTOR was required to strongly suppress drug combination lethality. As both lapatinib and sorafenib are FDA approved agents, our data argue for further determination as to whether lapatinib and sorafenib is a useful glioblastoma therapy.

Nexavar/Stivarga and viagra interact to kill tumor cells.

We determined whether the multi-kinase inhibitor sorafenib or its derivative regorafenib interacted with phosphodiesterase 5 (PDE5) inhibitors such as Viagra (sildenafil) to kill tumor cells. PDE5 and PDGFRα/ß were over-expressed in liver tumors compared to normal liver tissue. In multiple cell types in vitro sorafenib/regorafenib and PDE5 inhibitors interacted in a greater than additive fashion to cause tumor cell death, regardless of whether cells were grown in 10 or 100% human serum. Knock down of PDE5 or of PDGFRα/ß recapitulated the effects of the individual drugs. The drug combination increased ROS/RNS levels that were causal in cell killing. Inhibition of CD95/FADD/caspase 8 signaling suppressed drug combination toxicity. Knock down of ULK-1, Beclin1, or ATG5 suppressed drug combination lethality. The drug combination inactivated ERK, AKT, p70 S6K, and mTOR and activated JNK. The drug combination also reduced mTOR protein expression. Activation of ERK or AKT was modestly protective whereas re-expression of an activated mTOR protein or inhibition of JNK signaling almost abolished drug combination toxicity. Sildenafil and sorafenib/regorafenib interacted in vivo to suppress xenograft tumor growth using liver and colon cancer cells. From multiplex assays on tumor tissue and plasma, we discovered that increased FGF levels and ERBB1 and AKT phosphorylation were biomarkers that were directly associated with lower levels of cell killing by 'rafenib + sildenafil. Our data are now being translated into the clinic for further determination as to whether this drug combination is a useful anti-tumor therapy for solid tumor patients.

OSU-03012 and Viagra Treatment Inhibits the Activity of Multiple Chaperone Proteins and Disrupts the Blood-Brain Barrier: Implications for Anti-Cancer Therapies.

We examined the interaction between OSU-03012 (also called AR-12) with phosphodiesterase 5 (PDE5) inhibitors to determine the role of the chaperone glucose-regulated protein (GRP78)/BiP/HSPA5 in the cellular response. Sildenafil (Viagra) interacted in a greater than additive fashion with OSU-03012 to kill stem-like GBM cells. Treatment of cells with OSU-03012/sildenafil: abolished the expression of multiple oncogenic growth factor receptors and plasma membrane drug efflux pumps and caused a rapid degradation of GRP78 and other HSP70 and HSP90 family chaperone proteins. Decreased expression of plasma membrane receptors and drug efflux pumps was dependent upon enhanced PERK-eIF2α-ATF4-CHOP signaling and was blocked by GRP78 over-expression. In vivo OSU-03012/sildenafil was more efficacious than treatment with celecoxib and sildenafil at killing tumor cells without damaging normal tissues and in parallel reduced expression of ABCB1 and ABCG2 in the normal brain. The combination of OSU-03012/sildenafil synergized with low concentrations of sorafenib to kill tumor cells, and with lapatinib to kill ERBB1 over-expressing tumor cells. In multiplex assays on plasma and human tumor tissue from an OSU-03012/sildenafil treated mouse, we noted a profound reduction in uPA signaling and identified FGF and JAK1/2 as response biomarkers for potentially suppressing the killing response. Inhibition of FGFR signaling and to a lesser extent JAK1/2 signaling profoundly enhanced OSU-03012/sildenafil lethality.

PDE5 inhibitors enhance celecoxib killing in multiple tumor types.

The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with a clinically relevant NSAID, celecoxib, to kill tumor cells. Celecoxib and PDE5 inhibitors interacted in a greater than additive fashion to kill multiple tumor cell types. Celecoxib and sildenafil killed ex vivo primary human glioma cells as well as their associated activated microglia. Knock down of PDE5 recapitulated the effects of PDE5 inhibitor treatment; the nitric oxide synthase inhibitor L-NAME suppressed drug combination toxicity. The effects of celecoxib were COX2 independent. Over-expression of c-FLIP-s or knock down of CD95/FADD significantly reduced killing by the drug combination. CD95 activation was dependent on nitric oxide and ceramide signaling. CD95 signaling activated the JNK pathway and inhibition of JNK suppressed cell killing. The drug combination inactivated mTOR and increased the levels of autophagy and knock down of Beclin1 or ATG5 strongly suppressed killing by the drug combination. The drug combination caused an ER stress response; knock down of IRE1α/XBP1 enhanced killing whereas knock down of eIF2α/ATF4/CHOP suppressed killing. Sildenafil and celecoxib treatment suppressed the growth of mammary tumors in vivo. Collectively our data demonstrate that clinically achievable concentrations of celecoxib and sildenafil have the potential to be a new therapeutic approach for cancer.

Phosphodiesterase 5 inhibitors enhance chemotherapy killing in gastrointestinal/genitourinary cancer cells.

The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with clinically relevant chemotherapies to kill gastrointestinal/genitourinary cancer cells. In bladder cancer cells, regardless of H-RAS mutational status, at clinically achievable doses, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/mitomycin C/gemcitabine/cisplatin/paclitaxel to cause cell death. In pancreatic tumor cells expressing mutant active K-RAS, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/gemcitabine/paclitaxel to cause cell death. The most potent PDE5 inhibitor was sildenafil. Knock down of PDE5 expression recapitulated the combination effects of PDE5 inhibitor drugs with chemotherapy drugs. Expression of cellular FLICE-like inhibitory protein-short did not significantly inhibit chemotherapy lethality but did significantly reduce enhanced killing in combination with sildenafil. Overexpression of B-cell lymphoma-extra large suppressed individual and combination drug toxicities. Knock down of CD95 or Fas-associated death domain protein suppressed drug combination toxicity. Combination toxicity was also abolished by necrostatin or receptor interacting protein 1 knock down. Treatment with PDE5 inhibitors and chemotherapy drugs promoted autophagy, which was maximal at ∼24 hour posttreatment, and 3-methyl adenine or knock down of Beclin1 suppressed drug combination lethality by ∼50%. PDE5 inhibitors enhanced and prolonged the induction of DNA damage as judged by Comet assays and γhistone 2AX (γH2AX) and checkpoint kinase 2 (CHK2) phosphorylation. Knock down of ataxia telangiectasia mutated suppressed γH2AX and CHK2 phosphorylation and enhanced drug combination lethality. Collectively our data demonstrate that the combination of PDE5 inhibitors with standard of care chemotherapy agents for gastrointestinal/genitourinary cancers represents a novel modality.

Delayed Postoperative Intracerebral Hemorrhage Associated With Oral Multikinase Inhibitor Therapy for Cancer: A Case Report.

Regorafenib is a multikinase inhibitor with anti-vascular endothelial growth factor receptor (VEGF) activity used as an antiangiogenic agent for metastatic colorectal cancer treatment and has been studied as a potential therapeutic agent for several other cancer treatments. Adverse reactions commonly reported with the use of regorafenib and similar oral multikinase inhibitors include hemorrhage, gastrointestinal fistulas, hypertension, and incomplete wound healing. We report a case of a 59-year-old man with metastatic colorectal adenocarcinoma post-colostomy on regorafenib treatment presenting to the emergency department with altered mental status. MRI showed a left frontoparietal mass, which was resected with a left frontal craniotomy. Postoperative MRI showed a resection cavity without significant hemorrhage. He had been prescribed regorafenib preceding his hospitalization, which was continued after admission before surgery and on postoperative day 1. Thirty-two hours after surgery, the patient exhibited sudden right-sided facial droop and right arm weakness. Imaging revealed an acute intraparenchymal hemorrhage within and adjacent to the tumor resection bed, which was managed conservatively. The patient was subsequently discharged to an inpatient rehabilitation facility. The unusual timing of the hemorrhage suggests that the hemorrhage was due to adverse effects of regorafenib. Patients undergoing neurosurgery should have regorafenib discontinued in preparation for surgery. Similar management should be considered for other anti-VEGF medications to avoid serious complications.