Abstract 4758
Background
HPV induces many alterations in CDK4-Cyclin D-Rb and apoptotic pathways such as up-regulation of p16, loss of Rb and p53 functions in SCCHN carcinogenesis. Loss of p16 expression is known as a poor prognostic marker in SCCHN for survival. Palbociclib is a highly selective inhibitor of CDK4/6 by blocking Rb phosphorylation with radiosensitizing activity in preclinical studies. Addition of palbociclib to cetuximab and IMRT provides a strong rationale to improve efficacy of treatment in locally advanced SCCHN, especially in p16/HPV-negative tumour.
Methods
This is a phase I study designed to determine the maximum tolerated dose (MTD) and toxicity of palbociclib, cetuximab, and IMRT, using a classical 3 + 3 design (NCT03024489). The study included locally advanced SCCHN of oral cavity, oropharynx, larynx, and hypopharynx. Palbociclib dose was escalated with 3 dose levels (DLs), starting from 75 to 125 mg/d orally for 21 day-on and 7 day-off for 2 cycles. For all DLs, cetuximab was administered at 400 mg/m2IV on day -7 and then 250 mg/m2weekly for 7 weeks. IMRT was delivered 5 day-on and 2 day-off with a total dose of 70 Gy for 33 fractions. MRI and PET scans pre- and post-treatment was used to evaluate preliminary efficacy.
Results
A total of 13 eligible patients were enrolled in the dose escalation cohort. No MTD was observed. One DLT, febrile neutropenia (FN) was reported in 1 of 7 patients who received 125 mg of palbociclib (DL3) at the 6thweek of IMRT. The FN recovered without G-CSF support within 7 days after discontinuation of palbociclib. Overall, toxicities were related to cetuximab and IMRT. Complete response was observed in 7 of 10 evaluable patients (70%), while overall objective response was demonstarted in 9 of 10 patients (90%).
Conclusions
The recommended phase 2 dose was palbociclib 125 mg/d for 21 days on and 7 days off with full standard dose of cetuximab and IMRT for locally advanced SCCHN. MTD was not achieved. The combination was well tolerated with promising preliminary efficacy. The expansion cohort of palbociclib 125 mg/d is currently accruing up to 15 locally advanced p16-negative SCCHN patients.
Clinical trial identification
NCT#03024489.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Pfizer.
Disclosure
N. Ngamphaiboon: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution), Travel / Accommodation / Expenses: Roche; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): AstraZeneca; Honoraria (self), Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Eisai; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Amgen; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution), Travel / Accommodation / Expenses: MSD; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Novartis; Advisory / Consultancy: Boehringer Ingelheim; Travel / Accommodation / Expenses: Merck; Travel / Accommodation / Expenses: Taiho. T. Siripoon: Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Boehringer Ingelheim. S. Lukerak: Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): MSD; Research grant / Funding (institution): AstraZeneca. N. Sankaseam: Research grant / Funding (institution): Roche; Research grant / Funding (institution): MSD; Research grant / Funding (institution): AstraZeneca. E. Sirachainan: Honoraria (self), Travel / Accommodation / Expenses: MSD; Honoraria (self): Sanofi/Aventis; Honoraria (self): Merck; Honoraria (self), Travel / Accommodation / Expenses: Amgen; Honoraria (self), Travel / Accommodation / Expenses: Roche; Travel / Accommodation / Expenses: Mundipharma; Honoraria (self), Research grant / Funding (institution), Travel / Accommodation / Expenses: AstraZeneca; Honoraria (self): LF Asia; Honoraria (self): Diethelm Keller Logistics; Honoraria (self): BMS; Honoraria (self): Boehringer Ingelheim. All other authors have declared no conflicts of interest.
Resources from the same session
2600 - Atezolizumab (atezo) vs chemotherapy (chemo) in patients (pts) with platinum-treated locally advanced or metastatic urothelial carcinoma (mUC): a long-term overall survival (OS) and safety update from the Phase III IMvigor211 study
Presenter: Michiel Van der Heijden
Session: Poster Display session 3
Resources:
Abstract
3598 - Three-Year Follow-Up From the Phase 3 KEYNOTE-045 Trial: Pembrolizumab (Pembro) Versus Investigator’s Choice (Paclitaxel, Docetaxel, or Vinflunine) in Recurrent, Advanced Urothelial Cancer (UC)
Presenter: Andrea Necchi
Session: Poster Display session 3
Resources:
Abstract
2382 - First Report of Efficacy and Safety From a Phase 2 Trial of Tislelizumab, an Anti-PD-1 Antibody, for the Treatment of PD-L1+ Locally Advanced or Metastatic Urothelial Carcinoma (UC) in Asian Patients
Presenter: Dingwei Ye
Session: Poster Display session 3
Resources:
Abstract
2388 - Quality of Life of Metastatic Urothelial Cancer (mUC) Patients Treated with Enfortumab Vedotin (EV) Following Platinum-Containing Chemotherapy and a Checkpoint Inhibitor (CPI): Data from EV-201 Cohort 1
Presenter: Bradley McGregor
Session: Poster Display session 3
Resources:
Abstract
3748 - Safety and efficacy of atezolizumab (atezo) in patients (pts) with autoimmune disease (AID): subgroup analysis of the SAUL study in locally advanced/metastatic urinary tract carcinoma
Presenter: Yohann Loriot
Session: Poster Display session 3
Resources:
Abstract
1126 - Validation of the VIO prognostic index in patients with metastatic urothelial carcinoma treated with immune-checkpoint inhibitors
Presenter: Rafael Morales Barrera
Session: Poster Display session 3
Resources:
Abstract
3693 - Pathologic outcomes after neoadjuvant chemotherapy for high-risk muscle invasive bladder cancer
Presenter: Justin Matulay
Session: Poster Display session 3
Resources:
Abstract
4840 - Analysis of response to prior therapies and therapies after treatment with erdafitinib in fibroblast growth factor receptor (FGFR)-positive patients (pts) with metastatic urothelial carcinoma (mUC)
Presenter: Arlene Siefker-Radtke
Session: Poster Display session 3
Resources:
Abstract
1221 - Clinical outcomes by sex with atezolizumab (atezo) monotherapy in patients (pts) with locally advanced/metastatic urothelial carcinoma (mUC)
Presenter: Jean Hoffman-censits
Session: Poster Display session 3
Resources:
Abstract
1715 - National Small Cell Bladder Cancer Audit: Results from 26 UK institutions
Presenter: Caroline Chau
Session: Poster Display session 3
Resources:
Abstract