HPV-Related Head and Neck Cancer Guilherme Rabinowits M.D. Center for Head and Neck Oncology Instructor in Medicine Harvard Medical School Boston, MA

Disclosures Scientific Advisory Board for Onyx Pharmaceuticals Inc. Clinical Trial Support to Institution from Exelixis and Millenium

Introduction HNC - 6th most common cancer worldwide Historically tobacco and ETOH-related cancer Strong evidence linking HPV infection to HNC Increasing incidence of oropharynx cancers, while decrease incidence of other HNCs Proportion of HPV+ disease is increasing: epidemic North European and North American patients Preferentially identified in oropharynx cancer - tonsil and base of tongue HPV 16 is the predominant subtype (>90%) Ang NEJM 2010 Abogunrin BMC Cancer 2014

Patient and Tumor Characteristics Younger patient population Lower smoking rates Men > women Multiple sexual partners Oral sex practice Oropharynx most common location Small primary tumors and advanced nodal disease Cystic nodes Poorly differentiated, basaloid tumors Most pts with HPV+OPC are still men in their 50’s who have a smoking hx. True non-smokers constitutes only a minority D’Souza NEJM 2007 Gillison JNCI 2008 Chatuverdi JCO 2011

Molecular and Biological Events in HNC 5 HNC Can Now Be Divided Into 2 Large and Distinct Subtypes HPV-Related Cancers Environment-Related Cancers Caused by high-risk HPV HPV 16 Driven by viral oncogenes Restricted to oropharynx Distinct molecular markers “Good” prognosis Young, good general health Caused by environmental mutagens Smoking, alcohol Throughout oral mucosa Distinct molecular markers “Poor” prognosis, comorbidity Second primary cancers

Genomic Landscape Hayes et al ASCO 2013 PIK3CA activation promotes cell cycle activation, metabolism and trasncription factors that regulates diverse genes that promote the malignant phenotype Given that both wild-type (vs mutant) p53 and lower EGFR expression are correlated with treatment responsiveness and survival, these biologic differences may in part explain the difference in outcomes based upon HPV status. Additionally, HPV-associated tumors may be less hypoxic, which could increase responsiveness to radiotherapy. Hayes et al ASCO 2013

Proportion of Oropharynx Cancer, USA 1973-2005 New data from 2005 – 2011 revealed continuing alarming increases in age-specific incidence rates by birth cohort among all men born after 1940, age 40-70 years OPC is one of the only 5 cancer types that increased in incidence from 1975 – 2009 (CDC) Jemal JNCI 2013 32% 18% Chaturvedi and Gillison

Tumor HPV Prevalence D’Souza Prev. Med 2011

Latency Period Gillison JCO 2015

Screening Screening at this time for HPV+ OPC is infeasible Inability to detect precursor lesions and subclinical or early-stage cancers Absence of an established intervention to reduce cancer incidence and mortality

HPV Diagnostic Testing p16 immunohistochemistry (very sensitive) In situ hybridization for high risk HPV (very specific) PCR (both sensitive and specific) P16 IHC – procedural simplicity, ease of interpretation and excellent sensitivity P16 IHC x HPV ISH ~25% HPV-associated cases are determined based upon strong nuclear and cytoplasmic staining of at least 70% 11

HPV Oncoproteins Mohanti doi:10.4172/scientificreports.452 Integration of high-risk HPV DNA, into the human cellular genome is an important step in malignant transformation. The E6 oncoprotein disrupts the p53 pathway and causes subsequent degradation of the p53 protein, which results in loss of control at the G1/S and G2/M checkpoints making the cell susceptible to defective repair capacity as well as uncontrolled growth. The E7 oncoprotein is involved in the inactivation retinoblastoma tumor suppressor gene product pRb. Regulatory function of the Rb tumor suppressor protein appears to largely depend on the ability of Rb to bind to and inhibit the family of E2F transcription factors that encode proteins necessary for DNA synthesis, replication and maintenance of cell cycle regulation. The bound Rb-E2F protein serves as inhibitor of transcription for several genes regulating cell proliferation including p16 gene, phosphorylation of Rb leads to the release of the transcription factor E2F. The CyclinD-cdk4/6 complexes (CDKs), when not under the inhibition by p16 phosphorylate Rb leading to the release of the transcription factor E2F and initiating cell cycle progression. P16 regulates the activity of these CyclinD-cdk4/6 complexes. The E7 protein forms complexes with hypophosphorylated forms of the retinoblastoma tumor suppressor protein (pRb) resulting in release of E2F, thereby releasing p16 gene from its transcriptional inhibition and inducing transcription of various genes which lead to cell proliferation. Consequently HPV-positive tumors are characterized by high expression levels of p16  Mohanti doi:10.4172/scientificreports.452

HPV Status as a Prognostic Factor Modality Time HPV+ HPV- p Radiation (DAHANCA)1 5 yrs 62% 26% 0.0003 ChemoRT (TROG)2 2 yrs 91% 74% 0.004 ChemoRT (RTOG 0129)3 3 yrs 82% 57% 0.001 Sequential (ECOG)4 95% 0.005 Sequential (TAX324)5 35% 0.0001 1Lassen, JCO, 2009; 2Rischin, JCO, 2010; 3Ang NEJM, 2010; 4Fakhry, JNCI, 2008; 5Posner Ann Onc, 2011

Treatment Toxicity Acute: mucositis, dermatitis, dysphagia, odynophagia Chronic: xerostomia, dysgeusia Can therapy for all HPV+ OPC be deintensified to decrease risk of acute and long-term toxicities? Are there other prognostic factors within OPC other than HPV status?

Stage III/IV (T2, N2-3, M0 or T3-4, any N, M0) SCCHN RTOG 0129 Phase III Trial: Concomitant CRT With Standard vs. Accelerated Fractionation RT CRT Stage III/IV (T2, N2-3, M0 or T3-4, any N, M0) SCCHN Oral cavity, oropharynx, hypopharynx, and larynx No previous treatment N=743 Cisplatin (IV on d1, d22, d43) Standard fractionation RT (5 d/wk for 7 wks) R A N D O M I Z E Cisplatin (IV on d1 and d22) Accelerated fractionation RT (5 d/wk for 3.5 wks; then bid, 5 d/wk for 2.5 wks) 3-year OS, PFS or pattern of relapse were similar between groups Ang NEJM 2010 15

RTOG 0129: HPV Analysis 433 (60%) of 721 had OP primary 323 (75%) of 433 had HPV testing 206 (64%) of 323 were HPV+ P16-positive P16-negative HPV-positive 192 (93%) 7 (3%) HPV-negative 22 (19%) 94 (80%) Kappa = 0.80: 95%CI 0.73-0.87 Ang NEJM 2010

RTOG 0129: OS and PFS by HPV Status 100 75 50 25 OS 100 75 50 25 PFS OS (%) HPV negative HPV positive HPV negative HPV positive HR=0.38 (95% CI: 0.26-0.55); P<0.001 HR=0.40 (95% CI: 0.29-0.557; P<0.001 3-Yr Outcomes HPV Positive (%) HPV Negative (%) P Value OS 82.4 57.1 <0.001 PFS 73.7 43.4 Locoregional failure 13.6 35.1 Distant metastases 8.7 14.6 0.23 Ang NEJM 2010 17

RTOG 0129 RPA: HPV, Smoking Status, Staging RPA: Statistical Method for Multivariable Analysis; Creates a Classification of a Population Based on Independent Variables Ang NEJM 2010

Risk Groups Risk Characteristics 3-year OS Low HPV+, Non-Smoker HPV+, Smoker N0-2a 93% (95% CI, 88.3-97.7) Intermediate HPV+, Smoker, N2b-3 HPV-, Non-Smoker T2-3 71% (95% CI, 60.7-80.8) High HPV-, Non-Smoker, T4 HPV-, Smoker 46% (95% CI, 34.7-57.7) Ang NEJM 2010

LC RC DC Retrospective analysis OPC treated with RT or CRT 2001-2009 Risk of distant metastasis HPV+ OPC Similar risk of distant metastasis despite differences in loco-regional control LC RC DC HPV+ 94% 95% 90% HPV- 80% 82% 86% P<0.01 P=0.53 Median f/u 3.9 years O’Sullivan JCO 2013

PMH RPA HPV Positive Low Risk Modified Multivariate analysis identified that HPV negativity (hazard ratio [HR], 2.9; 95% CI, 2.0 to 5.0), N2b-N3 (HR, 2.9; 95% CI, 1.8 to 4.9), T4 (HR, 1.8; 95% CI, 1.2 to 2.9), and RT alone (HR, 1.8; 95% CI, 1.1 to 2.5) predicted a lower recurrence-free survival. More than 10 pack-year smokers had a lower 3-year OS compared with their ≤ 10 pack-year counterparts (77% [95% CI, 70% to 82%] v 89% [95% CI, 84% to 93%], respectively; P < .001) but similar RFS (86% [95% CI, 79% to 90%] v 83% [95% CI, 77% to 88%], respectively;P = .43). The late toxicity rate was marginally higher in more than 10 pack-year smokers (13% v 21% for ≤ 10 pack-year smokers; P = .06). A higher proportion of more than 10 pack-year smokers developed a second primary cancer (11% v 4% for ≤ 10 pack-year smokers; P = .009; Table 1). HPV Positive Low Risk Modified *N2c removed from final grouping -Difference for RT vs CRT *Also remove N2b heavy smokers O’Sullivan JCO 2013

PMH Results HPV+ group recommended for deintensification: Low risk: T1-T3, N0-N2c (DC 93%; LRC 95%) High risk: T4, N3 (DC 78%; LRC 82%) HPV- Low risk: T1-T2, N0-N2c (DC 93%; LRC 76%) High risk: T3-T4, N3 (DC 72%; LRC 62%) The DC rates for HPV-positive, low-risk N0-2a or less than 10 pack-year N2b patients were similar for RT alone and CRT, but the rate was lower in the N2c subset managed by RT alone (73% v 92% for CRT; P = .02). HPV+ group recommended for deintensification: T1-T3, N0-N2a T1-T3, N2b <10 Pack-Years O’Sullivan JCO 2013

What about Clinical Trials and Future Directions?

Treatment Deintensification Strategies Reduced radiation dose Reduced concurrent chemotherapy dose Substitute biologic agent for chemotherapy Use induction chemotherapy to select responders and then reduce radiation dose 24 24

Cetuximab loading dose = 400mg/m2 on Day1 of Cycle1 with Induction E1308: Phase II HPV-specific Trial Chemotherapy to Select Patients for Lower Dose Radiation INDUCTION (3 cycles) Weekly Paclitaxel + Weekly Cetuximab Q3 wks Cisplatin ELIGIBILITY Stage III, IVA Resectable HPV or P16+ Oropharynx CONCURRENT IMRT 54Gy/27 fxs Cetuximab 250mg/m2 qwk CR CONCURRENT IMRT 69.3Gy/33fxs Cetuximab 250mg/m2 qwk <CR N=80 Cetuximab loading dose = 400mg/m2 on Day1 of Cycle1 with Induction

E1308: Results Endpoint: 2-year PFS and OS Cohort (n) 2-year PFS (90% CI) 2-year OS (90% CI) All low dose pts (62) 0.8 (0.7, 0.88) 0.93 (0.85, 0.97) T4a (7) 0.54 (0.19, 0.79) 0.86 (0.45, 0.97) Non-T4a (55) 0.84 (0.73, 0.91) 0.94 (0.86, 0.98) N2c (19) 0.77 (0.56, 0.89) 0.95 (0.76, 0.99) Non-N2c (43) 0.82 (0.69, 0.9) 0.93 (0.82, 0.97) Smoker > 10pk-yrs (22) 0.57 (0.35, 0.73) 0.86 (0.67, 0.94) Smoker < 10 pk-yrs (40) 0.92 (0.81, 0.97) 0.97 (0.87, 0.995) Smoker < 10pk-yrs, <T4, <N2c (27) 0.96 (0.82, 0.99) All high dose pts (15; 3 didn’t get RT) 0.65 (0.41, 0.82) 0.87 (0.63, 0.96) 23% dose reduction in RT allowed for a significant reduction in toxicity while maintaining high PFS and OS Cmelak ASCO 2014, adapted

RTOG 1016: A Randomized Phase III Trial of RT with Cisplatin or Cetuximab in P16+ OPC 27 RANDOMIZE Cisplatin 100 mg/m2/q21d ELIGIBILITY Stage III, IVA/B Resectable P16+ Oropharynx Cancer IMRT 70Gy Cetuximab 400/250 mg/m2 weekly IMRT 70Gy Stratify: HPV, smoking, stage Cetuximab loading dose = 400 mg/m2 on Day 1 of Cycle1 with induction 27

RTOG 1333: A Randomized Phase II Trial of Lower Dose RT with or without Cisplatin in HPV+ OPC 28 RANDOMIZE Cisplatin 40 mg/m2/qwk ELIGIBILITY Stage T1-2 N1-2b T3N0-2b < 10 pack/yr HPV+ OPC IMRT 60Gy IMRT 60Gy 28

29 ECOG 3311 – Phase II Randomized Trial of TORS followed by Low- or Standard-dose IMRT in Resectable p16+ Locally Advanced OPC LOW RISK: T1-T2N0-N1 negative margins Observation Assess Eligibility: HPV (p16+) OPC Stage III-IV: cT1-2, N1-2b (no T1N1) Baseline Functional/ QOL Assessment Radiation Therapy IMRT 50Gy/25 Fx RANDOMIZE INTERMEDIATE: Close margins < 1 mm ECS 2–4 metastatic LN PNI LVI Evaluate for 2-yr PFS Local-Regional Recurrence, Functional Outcomes/QOL Transoral Resection (any approach) with neck dissection Radiation Therapy IMRT 60 Gy/30 Fx HIGH RISK: Positive Margins > 1 mm ECS or ≥ 5 metastatic LN Radiation Therapy IMRT 66 Gy/33 Fx + CDDP 40 mg/m2 wkly 29

Conclusions Majority of OPC are now HPV 16 related Better prognosis regardless of standard therapy applied Specific HPV+ sub-groups do better independent of staging Future standard treatment for these patients is undefined Deintensification remains investigational and should not be done outside of a clinical trial As treatment deintensification proves successful, we hope the quality of life for cured patients significantly improves

Thank You !!