byl719 and Squamous-Cell-Carcinoma-of-Head-and-Neck

Alpelisib in combination with cetuximab showed synergistic anti-tumour activity in head and neck squamous cell carcinoma (HNSCC) models.. The recommended phase 2 dose (RP2D) was determined in a phase 1b dose-escalation study. Phase 2 evaluated anti-tumour activity with a randomised part in cetuximab-naïve patients and a non-randomised part in cetuximab-resistant patients..  Alpelisib was administered in 28 d cycles as whole tablets, suspension from crushed tablets or suspension from dispersible tablets in patients with platinum-resistant, recurrent/metastatic HNSCC.. The RP2D determined for alpelisib was 300 mg/d. Alpelisib-cetuximab achieved an overall response rate of 25% and 9.9% and disease control rate of 75% and 43.7% in phase 1b and phase 2 studies, respectively. Median progression-free survival (PFS) per central review was 86 d for combination treatment and 87 d for cetuximab monotherapy (unadjusted HR 1.12; 95% CI 0.69-1.82; P > 0.05). When adjusted for baseline covariates [sum of longest diameters from central data, haemoglobin and white blood cell (WBC), the results favoured combination treatment (adjusted HR 0.54; 95% CI 0.30-0.97; P = 0.039). PFS per investigator assessment resulted in an unadjusted HR of 0.76 (95% CI 0.49-1.19; P > 0.05) favouring combination treatment. The median PFS in cetuximab-resistant patients was 3.9 months.. The addition of alpelisib to cetuximab did not demonstrate a PFS benefit in cetuximab-naïve patients with advanced HNSCC. The alpelisib-cetuximab combination showed moderate activity in cetuximab-resistant patients, with a consistent safety profile.. ClinicalTrials.gov NCT01602315; EudraCT 2011-006017-34.

Topics: Antineoplastic Combined Chemotherapy Protocols; Cetuximab; Head and Neck Neoplasms; Humans; Neoplasm Recurrence, Local; Squamous Cell Carcinoma of Head and Neck

Deregulation of the PI3K signalling pathway is frequent in squamous cell carcinoma of the head and neck (SCCHN) and may be implicated in radioresistance. We report on the results from a phase I 3 + 3 dose escalation study of alpelisib, a class I α-specific PI3K inhibitor in combination with concurrent cisplatin-based chemoradiation (CRT) in patients with locoregionally advanced SCCHN (LA-SCCHN).. Eligible patients had previously untreated LA-SCCHN and were candidates for CRT. The primary objective was to evaluate safety and determine the recommended phase II dose (RP2D). Alpelisib was given orally once daily at two dose levels: 200 mg and 250 mg. CRT consisted of cisplatin 100 mg/m. Nine patients were enrolled (six alpelisib 200 mg, three 250 mg). Oropharynx was the primary site in all patients (seven p16-positive; five T1-2N2M0, four T3-4N2-3M0 [AJCC 7th edition]). All patients completed CRT within seven weeks. Grade 3 alpelisib-related toxicities occurred in four patients. No dose-limiting toxicity (DLT) was observed at 200 mg among three DLT-evaluable patients. Two of two DLT-evaluable patients treated at 250 mg experienced DLTs (inability to complete ≥75% alpelisib secondary to radiation dermatitis and febrile neutropenia). Thus, RP2D was declared at 200 mg. After median follow-up of 39.7 months, two patients developed pulmonary metastases despite locoregional control. Three-year overall survival was 77.8% (95% CI 36.5%-93.9%).. Alpelisib at 200 mg has a manageable safety profile in combination with cisplatin-based CRT in LA-SCCHN.

Topics: Aged; Chemoradiotherapy; Cisplatin; Female; Humans; Middle Aged; Squamous Cell Carcinoma of Head and Neck; Thiazoles

Outcomes for patients with recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) are poor, with median overall survival (OS) ranging from 6 to 18 months. For those who progress on standard-of-care (chemo)immunotherapy, treatment options are limited, necessitating the development of rational therapeutic strategies. Toward this end, we targeted the key HNSCC drivers PI3K-mTOR and HRAS via the combination of tipifarnib, a farnesyltransferase (FTase) inhibitor, and alpelisib, a PI3Kα inhibitor, in multiple molecularly defined subsets of HNSCC. Tipifarnib synergized with alpelisib at the level of mTOR in PI3Kα- or HRAS-dependent HNSCCs, leading to marked cytotoxicity in vitro and tumor regression in vivo. On the basis of these findings, the KURRENT-HN trial was launched to evaluate the effectiveness of this combination in PIK3CA-mutant/amplified and/or HRAS-overexpressing R/M HNSCC. Preliminary evidence supports the clinical activity of this molecular biomarker-driven combination therapy. Combined alpelisib and tipifarnib has potential to benefit >45% of patients with R/M HNSCC. By blocking feedback reactivation of mTORC1, tipifarnib may prevent adaptive resistance to additional targeted therapies, enhancing their clinical utility.. The mechanistically designed, biomarker-matched strategy of combining alpelisib and tipifarnib is efficacious in PIK3CA- and HRAS-dysregulated head and neck squamous carcinoma and could improve outcomes for many patients with recurrent, metastatic disease. See related commentary by Lee et al., p. 3162.

Topics: Biomarkers; Carcinoma, Squamous Cell; Class I Phosphatidylinositol 3-Kinases; Head and Neck Neoplasms; Humans; Neoplasm Recurrence, Local; Proto-Oncogene Proteins p21(ras); Squamous Cell Carcinoma of Head and Neck; TOR Serine-Threonine Kinases

Blocking the mitogen-activated protein kinase (MAPK) pathway with the MEK1/2 inhibitor trametinib has produced promising results in patients with head and neck squamous cell carcinoma (HNSCC). In the current study, we showed that trametinib treatment leads to overexpression and activation of the epidermal growth factor receptor (EGFR) in HNSCC cell lines and patient-derived xenografts. Knockdown of EGFR improved trametinib treatment efficacy both in vitro and in vivo. Mechanistically, we demonstrated that trametinib-induced EGFR overexpression hyperactivates the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. In vitro, blocking the PI3K pathway with GDC-0941 (pictilisib), or BYL719 (alpelisib), prevented AKT pathway hyperactivation and enhanced the efficacy of trametinib in a synergistic manner. In vivo, a combination of trametinib and BYL719 showed superior antitumor efficacy vs. the single agents, leading to tumor growth arrest. We confirmed our findings in a syngeneic murine head and neck cancer cell line in vitro and in vivo. Taken together, our findings show that trametinib treatment induces hyperactivation of EGFR/PI3K/AKT; thus, blocking of the EGFR/PI3K pathway is required to improve trametinib efficacy in HNSCC.

Topics: Animals; Cell Line, Tumor; ErbB Receptors; Head and Neck Neoplasms; Humans; Mice; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Squamous Cell Carcinoma of Head and Neck

Alpelisib selectively inhibits the p110α catalytic subunit of PI3Kα and is approved for treatment of breast cancers harboring canonical PIK3CA mutations. In head and neck squamous cell carcinoma (HNSCC), 63% of PIK3CA mutations occur at canonical hotspots. The oncogenic role of the remaining 37% of PIK3CA noncanonical mutations is incompletely understood. We report a patient with HNSCC with a noncanonical PIK3CA mutation (Q75E) who exhibited a durable (12 months) response to alpelisib in a phase II clinical trial. Characterization of all 32 noncanonical PIK3CA mutations found in HNSCC using several functional and phenotypic assays revealed that the majority (69%) were activating, including Q75E. The oncogenic impact of these mutations was validated in 4 cellular models, demonstrating that their activity was lineage independent. Further, alpelisib exhibited antitumor effects in a xenograft derived from a patient with HNSCC containing an activating noncanonical PIK3CA mutation. Structural analyses revealed plausible mechanisms for the functional phenotypes of the majority of the noncanonical PIK3CA mutations. Collectively, these findings highlight the importance of characterizing the function of noncanonical PIK3CA mutations and suggest that patients with HNSCC whose tumors harbor activating noncanonical PIK3CA mutations may benefit from treatment with PI3Kα inhibitors.

Topics: Animals; Class I Phosphatidylinositol 3-Kinases; Head and Neck Neoplasms; Humans; Male; Mice; Middle Aged; Mutation; Protein Domains; Squamous Cell Carcinoma of Head and Neck; Thiazoles

High expression of the 110 kDa catalytic subunit of the class IA PI3K (PI3Kp110α) may play an important role in cetuximab resistance exhibited by both colorectal cancer and head and neck squamous cell carcinoma. Therefore, the present study aimed to examine the association between the expression of proteins in the PI3Kp110α pathway and cetuximab resistance, and the antitumor effects of alpelisib (PI3K inhibitor) and cetuximab in oral squamous cell carcinoma (OSCC) cells. The association between PI3Kp110α protein expression levels and the tumor response to cetuximab was determined using immunohistochemistry. OSCC cells were treated with alpelisib, cetuximab, or in combination, and the effects were examined in vitro and in vivo. PI3Kp110α protein expression was significantly associated with the tumor response to cetuximab (P<0.05) and 1‑year progression‑free survival and overall survival (P<0.05). Combined treatment of alpelisib and cetuximab resulted in enhanced antitumor effects in vitro compared with either agent administered alone. In particular, the expression level of N‑cadherin, an epithelial‑mesenchymal transition‑related protein, was decreased, suggesting that the invasion potential of cetuximab‑resistant cells decreased. Furthermore, the expression of proteins in the PI3K pathway were decreased in tumors from mice with OSCC xenografts treated with alpelisib and cetuximab in combination. These results indicate that novel regimens of systemic therapy (such as chemotherapy), with combinations of cetuximab and alpelisib, may be beneficial for patients with cetuximab‑resistant OSCC.

Topics: Aged; Aged, 80 and over; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cetuximab; Chemoradiotherapy, Adjuvant; Class I Phosphatidylinositol 3-Kinases; Drug Resistance, Neoplasm; Female; Humans; Male; Mice; Middle Aged; Mouth Mucosa; Mouth Neoplasms; Neoplasm Invasiveness; Progression-Free Survival; Retrospective Studies; Squamous Cell Carcinoma of Head and Neck; Thiazoles; Xenograft Model Antitumor Assays

Aberrant activation of the phosphatidylinositol 3-kinase (PI3K) pathway is common in many malignancies, including head and neck squamous cell carcinoma (HNSCC). Despite pre-clinical and clinical studies, outcomes from targeting the PI3K pathway have been underwhelming and the development of drug resistance poses a significant barrier to patient treatment. In the present study, we examined mechanisms of acquired resistance to the PI3Kα inhibitor alpelisib (formerly BYL719) in HNSCC cell lines and patient-derived xenografts (PDXs).. Five unique PDX mouse models and three HNSCC cell lines were used. All cell lines and xenografts underwent genomic characterization prior to study. Serial drug treatment was conducted in vitro and in vivo to develop multiple, clinically-significant models of resistance to alpelisib. We then used reverse phase protein arrays (RPPAs) to profile the expression of proteins in parental and drug-resistant models. Top hits were validated by immunoblotting and immunohistochemistry. Flow cytometric analysis and RNA interference studies were then used to interrogate the molecular mechanisms underlying acquired drug resistance.. Prolonged treatment with alpelisib led to upregulation of TAM family receptor tyrosine kinases TYRO3 and AXL. Importantly, a significant shift in expression of both TYRO3 and AXL to the cell surface was detected in drug-resistant cells. Targeted knockdown of TYRO3 and AXL effectively re-sensitized resistant cells to PI3Kα inhibition. In vivo, resistance to alpelisib emerged following 20-35 days of treatment in all five PDX models. Elevated TYRO3 expression was detected in drug-resistant PDX tissues. Downstream of TYRO3 and AXL, we identified activation of intracellular MAPK signalling. Inhibition of MAPK signalling also re-sensitized drug-resistant cells to alpelisib.. We have identified TYRO3 and AXL receptors to be key mediators of resistance to alpelisib, both in vitro and in vivo. Our findings suggest that pan-TAM inhibition is a promising avenue for combinatorial or second-line therapy alongside PI3Kα inhibition. These findings advance our understanding of the role TAM receptors play in modulating the response of HNSCC to PI3Kα inhibition and suggest a means to prevent, or at least delay, resistance to PI3Kα inhibition in order to improve outcomes for HNSCC patients.

Topics: Animals; Apoptosis; Axl Receptor Tyrosine Kinase; Biomarkers, Tumor; Cell Movement; Cell Proliferation; Class I Phosphatidylinositol 3-Kinases; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; Humans; MAP Kinase Signaling System; Mice; Prognosis; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Squamous Cell Carcinoma of Head and Neck; Survival Rate; Thiazoles; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

AXL overexpression is a common resistance mechanism to anti-cancer therapies, including the resistance to BYL719 (Alpelisib) - the p110α isoform specific inhibitor of phosphoinositide 3-kinase (PI3K) - in esophagus and head and neck squamous cell carcinoma (ESCC, HNSCC respectively). However, the mechanisms underlying AXL overexpression in resistance to BYL719 remain elusive. Here we demonstrated that the AP-1 transcription factors, c-JUN and c-FOS, regulate AXL overexpression in HNSCC and ESCC. The expression of AXL was correlated with that of c-JUN both in HNSCC patients and in HNSCC and ESCC cell lines. Silencing of c-JUN and c-FOS expression in tumor cells downregulated AXL expression and enhanced the sensitivity of human papilloma virus positive (HPVPos) and negative (HPVNeg) tumor cells to BYL719 in vitro. Blocking of the c-JUN N-terminal kinase (JNK) using SP600125 in combination with BYL719 showed a synergistic anti-proliferative effect in vitro, which was accompanied by AXL downregulation and potent inhibition of the mTOR pathway. In vivo, the BYL719-SP600125 drug combination led to the arrest of tumor growth in cell line-derived and patient-derived xenograft models, and in syngeneic head and neck murine cancer models. Collectively, our data suggests that JNK inhibition in combination with anti-PI3K therapy is a new therapeutic strategy that should be tested in HPVPos and HPVNeg HNSCC and ESCC patients.

Topics: Animals; Anthracenes; Antineoplastic Agents; Axl Receptor Tyrosine Kinase; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Drug Resistance, Neoplasm; Drug Synergism; Esophageal Neoplasms; Head and Neck Neoplasms; Humans; JNK Mitogen-Activated Protein Kinases; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, SCID; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Squamous Cell Carcinoma of Head and Neck; Thiazoles; Tongue; TOR Serine-Threonine Kinases; Transcription Factor AP-1; Xenograft Model Antitumor Assays

BYL719 is a PI3K inhibitor that has demonstrated efficacy in the treatment of head and neck squamous cell carcinoma. BYL719 exerts its therapeutic effect by suppressing AKT and other proliferative signaling mechanisms. Despite PI3K inhibition and AKT suppression, residual activity of protein S6, a core marker of proliferative activation, has been observed. HER3, either via dimerization or activation by its ligand neurgeulin (NRG), is known to activate PI3K. Thus, we hypothesized that co-targeting HER3 and PI3K would lead to greater suppression of the PI3K-AKT signaling pathway and greater tumor suppression than with BYL719 alone. We investigated biochemical expression and activation of the HER3-PI3K-AKT-S6 pathway in HNSCC cell lines and patient-derived xenografts (PDXs). Antitumor effects of HER3 and PI3K inhibitors alone and in combination were evaluated in cell culture and murine models. Treatment of HNSCC cell lines with BYL719 significantly reduced AKT activation and suppressed tumor growth. However, S6 was persistently activated despite suppression of AKT. Combination treatment with KTN3379, a monoclonal antibody targeted against HER3, and BYL719 led to enhanced suppression of in vitro and in vivo cancer growth and durable suppression of AKT and S6. Therefore, inhibition of HER3 with KTN3379 enhanced the effects of PI3K inhibition in pre-clinical HNSCC models. These data support co-targeting HER3 and PI3K for the treatment of HSNCC.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Humans; Mice; Molecular Targeted Therapy; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Receptor, ErbB-3; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; Thiazoles; Up-Regulation; Xenograft Model Antitumor Assays

The PI3K/AKT/mTOR pathway is frequently altered in head and neck squamous cell cancer (HNSCC), making this pathway a logical therapeutic target. However, PI3K targeting is not universally effective. Biomarkers of response are needed to stratify patients likely to derive benefit and exclude those unlikely to respond.. We examined the sensitivity of cell lines with constitutively-active (G12V mutant) HRAS and wild-type HRAS to PI3K inhibition using flow cytometry and cell viability assays. We then overexpressed and silenced HRAS and measured sensitivity to the PI3K inhibitor BYL719. Immunoblotting was used to determine activation of the PI3K pathway. MEK and mTOR inhibitors were then tested in HRAS mutant cells to determine their efficacy.. HRAS mutant cell lines were non-responsive to PI3K inhibition. Overexpression of HRAS led to reduced susceptibility to PI3K inhibition, while knockdown improved sensitivity. Immunoblotting revealed suppressed AKT phosphorylation upon PI3K inhibition in both wild-type and HRAS mutant cell lines, however mutant lines maintained phosphorylation of S6, downstream of mTOR. Targeting mTOR effectively reduced viability of HRAS mutant cells and we subsequently examined the ERK-TSC2-mTOR cascade as a mediator of resistance to PI3K inhibition.. HRAS mutant cells are resistant to PI3K inhibition and our findings suggest the involvement of a signalling intersection of the MAPK and PI3K pathways at the level of ERK-TSC2, leading to persistent mTOR activity. mTOR inhibition alone or in combination with MAPK pathway inhibition may be a promising therapeutic strategy for this subset of HNSCC tumors.

Topics: Cell Cycle; Cell Line, Tumor; Drug Resistance, Neoplasm; Genes, ras; Head and Neck Neoplasms; Humans; MAP Kinase Kinase Kinases; MAP Kinase Signaling System; Mechanistic Target of Rapamycin Complex 1; Molecular Targeted Therapy; Mutation, Missense; Neoplasm Proteins; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Protein Processing, Post-Translational; Proto-Oncogene Proteins p21(ras); Ribosomal Protein S6 Kinases; RNA Interference; Squamous Cell Carcinoma of Head and Neck; Thiazoles; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein