Even, Caroline

TPS6111 Background: Human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HNSCC) has surpassed cervical cancer as the most common HPV-related cancer in the US, with the majority being caused by HPV16. Persistent expression of HPV16 oncoproteins E6 and E7 by host genome may promote HNSCC. HPV16-positive HNSCC may be associated with poor clinical outcomes in the recurrent/metastatic (R/M) setting. PDS0101 (Versamune HPV) is an HPV16-immunotherapy that generates a potent, targeted T cell attack against HPV16 E6 & E7. In a Phase 2 study, PDS0101 plus pembrolizumab has shown encouraging safety and survival benefit in patients with HPV16-positive R/M HNSCC. (Weiss J et al. ESMO 2024. Poster 879P. NCT04260126). Methods: VERSATILE-003 is a global Phase 3, randomized, controlled, open-label study evaluating PDS0101 plus pembrolizumab vs. pembrolizumab in patients with HPV16-positive R/M HNSCC with PD-L1 positive disease (CPS ≥1). Key eligibility criteria include age ≥18-years-old, histologically- or cytologically-confirmed diagnosis of R/M HNSCC with primary tumor location of oropharynx, oral cavity, hypopharynx, or larynx and no prior systemic anticancer treatment in the R/M setting, HPV16 tumor positivity (centrally tested), PD-L1 positivity defined as CPS ≥ 1 using FDA-approved PD-L1 IHC 22C3 pharmDx kit, and measurable disease based on RECIST 1.1 confirmed by blinded independent central review (BICR). Patients will be randomized 2:1 to receive pembrolizumab 200 mg IV Q3W with PDS0101 1 mL SC administered concurrently during Cycles 1, 2, 3, 4, and 12 (investigational arm), or pembrolizumab 200 mg IV Q3W alone (control arm). The primary objective is to compare overall survival (OS) between the investigational and control arms. Secondary objectives include objective response rate (ORR), disease control rate (DCR), duration of response (DOR), and progression-free survival (PFS) using RECIST 1.1 and assessed by BICR. Exploratory objectives include tumor response assessed by investigator and by irRECIST, PFS2, quality of life as assessed by EQ-5D, QLQ-C30, and QLQ H&N35, and assessment of ctHPVDNA. Updated enrollment data will be provided. Clinical trial information: NCT06790966 .

PURPOSEMutations in the HRAS (m HRAS) proto-oncogene occur in 4%-8% of patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). Tipifarnib is a farnesyltransferase inhibitor that disrupts HRAS function. We evaluated the efficacy of tipifarnib in patients with R/M m HRAS HNSCC.METHODSWe enrolled 30 patients with R/M HNSCC in a single-arm, open-label phase II trial of tipifarnib for m HRAS malignancies; one additional patient was treated on an expanded access program. After an ad hoc analysis of the first 16 patients with HNSCC with m HRAS variant allele frequency (VAF) data, enrollment was limited to those with a m HRAS VAF of ≥ 20% (high VAF). The primary end point was objective response rate. Secondary end points included assessing safety and tolerability. Patients received tipifarnib 600 or 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles.RESULTSOf the 22 patients with HNSCC with high VAF, 20 were evaluable for response at the time of data cutoff. Objective response rate for evaluable patients with high-VAF HNSCC was 55% (95% CI, 31.5 to 76.9). Median progression-free survival on tipifarnib was 5.6 months (95% CI, 3.6 to 16.4) versus 3.6 months (95% CI, 1.3 to 5.2) on last prior therapy. Median overall survival was 15.4 months (95% CI, 7.0 to 29.7). The most frequent treatment-emergent adverse events among the 30 patients with HNSCC were anemia (37%) and lymphopenia (13%).CONCLUSIONTipifarnib demonstrated encouraging efficacy in patients with R/M HNSCC with HRAS mutations for whom limited therapeutic options exist ( NCT02383927 ).

Abstract Background: This Phase 2 study (NCT02383927) is a multi-institutional, open-label trial to determine the efficacy and safety of tipifarnib in patients (pts) with locally advanced/unresectable and/or metastatic solid tumors that carry HRAS missense mutations. HRAS is a proto-oncogene that is overexpressed and mutated in head and neck squamous cell carcinomas (HNSCC) and other SCCs. Tipifarnib is a potent and highly selective inhibitor of farnesyltransferase, a critical enzyme for HRAS activity. Methods: Pts received tipifarnib at a starting dose of 600 – 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles. Disease assessments were conducted according to RECIST v1.1 criteria. Null hypothesis and objective response of interest were respectively 10% and 30%. Prior to its completion, this study met its primary objective and, based on preliminary efficacy results (Ho, et. al, ESMO 2018), was amended to continue enrolling only pts with HNSCC (Cohort 2) and other SCC tumors (Cohort 3) carrying HRAS missense mutations at a high variant allele frequency (VAF >35% or ≥20% if baseline serum albumin is >3.5 g/dL). Results: As of May 1, 2019, 23 pts with HNSCC and 10 pts with tumors with other SCC histologies have been treated with tipifarnib. Pts had relapsed/refractory disease with a median of 2 prior regimens. Of note, no objective partial responses were observed on their last therapy prior to study entry, including platinum, immunotherapy and cetuximab +/- chemotherapy. In 15 HNSCC pts meeting the HRAS mutation high VAF inclusion criteria, a 53% overall response rate (ORR) was observed, with 8 confirmed partial responses (PR) and 5 disease stabilizations (SD). Two pts await first on-study tumor response assessment. Overall median progression free survival (PFS) was 5.4 mos (95% CI 4.5 to 19.5 mos, N=15); 19 mos (95% CI 5.3 to 19.5 mos) for pts experiencing a PR and 4.5 mos (95% CI 1.6 to 5.4 mos) for those experiencing SD. Median PFS on last prior therapy was 3.2 mos. All pts had at least 1 treatment-emergent adverse event (TEAE). The most frequently observed drug-related Grade >3 TEAEs occurring in ≥10% pts were blood and lymphatic system disorders, gastrointestinal disorders and renal disorders. Conclusions: Encouraging activity of tipifarnib was observed in HRAS mutant HNSCC. Based on these data, a pivotal study (AIM-HN and SEQ-HN Study, NCT03719690) evaluating the efficacy of this agent in HRAS mutant HNSCC (AIM-HN) and the impact of HRAS mutations on first line therapy of HNSCC (SEQ-HN) has been initiated. Citation Format: Alan Ho, Irene Brana, Robert Haddad, Jessica Bauman, Keith Bible, Laurence Faugeras, Sjoukje Oosting, Deborah J Wong, Myung-Ju Ahn, Valentina Boni, Caroline Even, Jerome Fayette, Maria Jose Flor, Kevin Harrington, Sung-Bae Kim, Lisa Licitra, Ioanna Nixon, Nabil F Saba, Cyrus Sayehli, Pol Specenier, Francis Worden, Binaifer Balsara, Jeanne Britt, Vishnu Mishra, Catherine Scholz, Antonio Gualberto. Preliminary results from a phase 2 trial of tipifarnib in squamous cell carcinomas (SCCs) with HRAS mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr PR08. doi:10.1158/1535-7163.TARG-19-PR08

Abstract Background: HRAS is a proto-oncogene that is mutated in head and neck, bladder, thyroid, and salivary gland tumors, among others. While discovered over 40 years ago, no specific therapies have yet been developed targeting mutant HRAS. Tipifarnib is a potent and highly selective inhibitor of farnesyltransferase, a critical enzyme requisite for HRAS activation. Over 5,000 patients (pts) have been treated with tipifarnib; although responses have been documented in several tumor indications, the mechanisms of response are still poorly understood. Tipifarnib has demonstrated robust activity in HRAS mutant patient derived xenograft (PDX) models of head and neck squamous cell carcinoma (HNSCC) and squamous non-small cell lung cancer that are resistant to standard therapies. This Phase 2 study (NCT02383927) was conducted to test the hypothesis that inhibition of mutant HRAS oncogenic activity with tipifarnib could translate to objective responses in HNSCC pts driven by the HRAS oncogene. Methods: The study was originally designed to enroll pts into 2 single-arm study cohorts: Cohort 1 (thyroid cancer) and Cohort 2 (other solid tumors), each one with a 2-stage design (11+7 evaluable pts) to determine overall response rate (ORR) as the primary objective. This design has 80% power to detect a difference between 10% and 30% ORR at one-sided significance level of 0.087. Two objective responses were needed to be observed in the first stage for each cohort to proceed to stage 2. The study is considered positive if at least 4 responses are observed in one of the 2 cohorts (N=18 each, stages 1 and 2 combined). The prespecified activity goal for the first stage of accrual in Cohort 2 was met and based on data observed in the first stage of this Cohort, ongoing enrollment to the second stage of Cohort 2 was limited to HRAS mutant HNSCC. For enrollment, pts must have an HRAS mutant, locally advanced/unresectable and/or metastatic solid tumor malignancy and RECIST v1.1 measurable disease. Tipifarnib is given at 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles. Response assessments are conducted every 8 weeks. Results: As of August 30, 2017, 28 pts have been enrolled. Tipifarnib was generally well tolerated with myelosuppression, gastrointestinal disturbances (nausea, vomiting and diarrhea) and fatigue constituting the most common adverse events (≥30% of pts, all grades). Twenty four pts are currently evaluable for efficacy: 10 in Cohort 1 and 14 in Cohort 2. Stage 1 enrollment continues in Cohort 1. The primary objective was met for Cohort 2 prior to completing full enrollment, with 4 confirmed responses observed out of 14 evaluable pts. Notably, of the 6 pts in Cohort 2 with HNSCC currently evaluable for efficacy, 4 (67%) achieved a confirmed partial response. Three of these pts remain on treatment in cycles 3, 5, and 19, and one subject discontinued at Cycle 21. Two (33%) pts had disease stabilization as best response (4 cycles, ongoing and 7 cycles). Importantly, 4 of these pts were refractory to prior therapies, including regimens containing immunotherapy (pembrolizumab, nivolumab) or cetuximab +/- chemotherapy. None of the 6 HNSCC patients experienced an objective partial response on their last prior therapy. Conclusions: These data suggest that HRAS mutant HNSCC pts may be refractory to standard therapies but can derive prolonged clinical benefit from tipifarnib treatment. Based on the encouraging activity of tipifarnib in pts with HNSCC with HRAS mutations, enrollment continues in this cohort. Citation Format: Alan Ho, Nicole Chau, Deborah J. Wong, Maria E. Cabanillas, Jessica Bauman, Marcia S. Brose, Keith Bible, Valentina Boni, Irene Brana, Charles Ferte, Caroline Even, Francis Burrows, Linda Kessler, Vishnu Mishra, Kelly Magnuson, Catherine Scholz, Antonio Gualberto. Preliminary results from a phase 2 proof of concept trial of tipifarnib in tumors with HRAS mutations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-A10.