Final analysis of phase II results with cemiplimab in metastatic basal cell carcinoma after hedgehog pathway inhibitors

BACKGROUND

Metastatic basal cell carcinoma (mBCC) is a rare condition with no effective second-line treatment options. Cemiplimab is an immune checkpoint inhibitor that blocks the binding of programmed cell death-1 (PD-1) to its ligands, programmed death-ligand 1 (PD-L1) and programmed death-ligand 2 (PD-L2). Here, we present the final analysis of cemiplimab in patients with mBCC after first-line hedgehog pathway inhibitor (HHI) treatment (NCT03132636).

PATIENTS AND METHODS

In this open-label, single-arm, phase II study, adults with mBCC and Eastern Cooperative Oncology Group performance status ≤1, post-HHI treatment, received cemiplimab 350 mg intravenously every 3 weeks for ≤93 weeks or until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by independent central review (ICR). Duration of response (DOR) was a key secondary endpoint. Other secondary endpoints were ORR per investigator assessment, progression-free survival (PFS), overall survival (OS), complete response rate, safety, and tolerability.

RESULTS

Fifty-four patients were enrolled: 70% were male and the median age of patients was 64 [interquartile range (IQR) 57.0-73.0] years. The median duration of follow-up was 8 months (IQR 4-21 months). The ORR per ICR was 22% [95% confidence interval (CI) 12% to 36%], with 2 complete responses and 10 partial responses. Among responders, the median time to response per ICR was 3 months (IQR 2-7 months). The estimated median DOR per ICR was not reached [95% CI 10 months-not evaluable (NE)]. The disease control rate was 63% (95% CI 49% to 76%) per ICR and 70% (95% CI 56% to 82%) per investigator assessment. The median PFS per ICR was 10 months (95% CI 4-16 months); the median OS was 50 months (95% CI 28 months-NE). The most common treatment-emergent adverse events were fatigue [23 (43%)] and diarrhoea [20 (37%)]. There were no treatment-related deaths.

CONCLUSIONS

Cemiplimab demonstrated clinically meaningful antitumour activity, including durable responses, and an acceptable safety profile in patients with mBCC who had disease progression on or intolerance to HHI therapy.

Pembrolizumab versus methotrexate, docetaxel, or cetuximab in recurrent or metastatic head and neck squamous cell carcinoma (KEYNOTE-040): Subgroup analysis by pattern of disease recurrence

BACKGROUND

In the phase 3 KEYNOTE-040 study, pembrolizumab prolonged OS versus chemotherapy in previously treated recurrent or metastatic (R/M) HNSCC. We present a post hoc subgroup analysis by disease recurrence pattern: recurrent-only, recurrent and metastatic (recurrent-metastatic), and metastatic-only HNSCC.

MATERIALS AND METHODS

Patients had HNSCC that progressed during or after platinum-containing treatment for R/M disease or had recurrence or progression within 3-6 months of previous platinum-containing definitive therapy for locally advanced disease. Patients were randomly assigned (1:1) to pembrolizumab 200 mg Q3W or investigator's choice of standards of care (SOC): methotrexate, docetaxel, or cetuximab. Outcomes included OS, PFS, ORR, and DOR. The data cutoff was May 15, 2017.

RESULTS

There were 125 patients (pembrolizumab, 53; SOC, 72) in the recurrent-only subgroup, 204 in the recurrent-metastatic subgroup (pembrolizumab, 108; SOC, 96), and 166 in the metastatic-only subgroup (pembrolizumab, 86; SOC, 80). The hazard ratio (95% CI) for death for pembrolizumab versus SOC was 0.83 (0.55-1.25) in the recurrent-only, 0.78 (0.58-1.06) in the recurrent-metastatic, and 0.74 (0.52-1.05) in the metastatic-only subgroups. PFS was similar between treatment arms in all subgroups. ORR was 22.6% for pembrolizumab versus 16.7% for SOC in the recurrent-only, 10.2% versus 6.3% in the recurrent-metastatic, and 15.1% versus 8.8% in the metastatic-only subgroups. DOR was numerically longer with pembrolizumab in all subgroups.

CONCLUSION

Pembrolizumab provided numerically longer OS and durable responses in all subgroups compared with SOC, suggesting that patients with previously treated R/M HNSCC benefit from pembrolizumab regardless of recurrence pattern.

Pan-Asian adaptation of the EHNS-ESMO-ESTRO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with squamous cell carcinoma of the head and neck

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of squamous cell carcinoma (SCC) of the oral cavity, larynx, oropharynx and hypopharynx was published in 2020. It was therefore decided by both the ESMO and the Korean Society of Medical Oncology (KSMO) to convene a special, virtual guidelines meeting in July 2021 to adapt the ESMO 2020 guidelines to consider the potential ethnic differences associated with the treatment of SCCs of the head and neck (SCCHN) in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with SCCHN (excluding nasopharyngeal carcinomas) representing the oncological societies of Korea (KSMO), China (CSCO), India (ISMPO), Japan (JSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence and was independent of the current treatment practices and drug access restrictions in the different Asian countries. The latter was discussed when appropriate. This manuscript provides a series of expert recommendations (Clinical Practice Guidelines) which can be used to provide guidance to health care providers and clinicians for the optimisation of the diagnosis, treatment and management of patients with SCC of the oral cavity, larynx, oropharynx and hypopharynx across Asia.

Late toxicities burden in patients with radioiodine-refractory differentiated thyroid cancer treated with lenvatinib

PURPOSE

Radioactive-iodine (RAI)-resistant differentiated thyroid cancer (DTC) patients benefit from multi-kinase inhibitors (MKIs), such as lenvatinib. Incidence of treatment-related (TR) late toxicities has been not yet described.

METHODS

From January 2015 to June 2019 we retrospectively reviewed clinical records of patients with RAI-resistant DTC treated with lenvatinib at Istituto Nazionale dei Tumori (Milan, Italy). New side effect of any grade, appeared after 12 months of lenvatinib, was defined as late adverse event (AE). Descriptive analyses were performed. Survival curves were estimated with Kaplan-Meier method and compared with log-rank test.

RESULTS

Thirty-seven patients were included, 65% had ≥65 years and 68% were female. Thirty patients received lenvatinib for >12 months. Lenvatinib was started at ≤20 mg/daily in 59% of patients, 64% were ≥65 years. The frequency of late AEs was 80% and cardiovascular toxicity was the most common (57%). There was no difference in the incidence of late AEs between younger/older population (77% and 82%, respectively). Median lenvatinib treatment duration (TD) was 39.96 months (95% CI 21.64-NR): 39.96 months for patients <65 years (95% CI: 13.25-NR) and 37.53 months for those ≥65 years, respectively (95% CI: 15.85-NR). Median overall survival (OS) was 39.96 months (95% CI: 21.84-NR), no statistically differences in OS was observed between younger (<65 years) and older patients (≥65 years) (HR 1.013; 95% CI 0.963-1.065; p = 0.62).

CONCLUSION

Late toxicity burden of lenvatinib is not negligible. Cardiovascular toxicity remains the principal side effect even after a prolonged lenvatinib exposition.

Durvalumab with or without tremelimumab in patients with recurrent or metastatic head and neck squamous cell carcinoma: EAGLE, a randomized, open-label phase III study

BACKGROUND

Targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis has demonstrated clinical benefit in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC). Combining immunotherapies targeting PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) has shown evidence of additive activity in several tumor types. This phase III study evaluated the efficacy of durvalumab (an anti-PD-L1 monoclonal antibody) or durvalumab plus tremelimumab (an anti-CTLA-4 monoclonal antibody) versus standard of care (SoC) in R/M HNSCC patients.

PATIENTS AND METHODS

Patients were randomly assigned to receive 1 : 1 : 1 durvalumab (10 mg/kg every 2 weeks [q2w]), durvalumab plus tremelimumab (durvalumab 20 mg/kg q4w plus tremelimumab 1 mg/kg q4w × 4, then durvalumab 10 mg/kg q2w), or SoC (cetuximab, a taxane, methotrexate, or a fluoropyrimidine). The primary end points were overall survival (OS) for durvalumab versus SoC, and OS for durvalumab plus tremelimumab versus SoC. Secondary end points included progression-free survival (PFS), objective response rate, and duration of response.

RESULTS

Patients were randomly assigned to receive durvalumab (n = 240), durvalumab plus tremelimumab (n = 247), or SoC (n = 249). No statistically significant improvements in OS were observed for durvalumab versus SoC [hazard ratio (HR): 0.88; 95% confidence interval (CI): 0.72-1.08; P = 0.20] or durvalumab plus tremelimumab versus SoC (HR: 1.04; 95% CI: 0.85-1.26; P = 0.76). The 12-month survival rates (95% CI) were 37.0% (30.9-43.1), 30.4% (24.7-36.3), and 30.5% (24.7-36.4) for durvalumab, durvalumab plus tremelimumab, and SoC, respectively. Treatment-related adverse events (trAEs) were consistent with previous reports. The most common trAEs (any grade) were hypothyroidism for durvalumab and durvalumab plus tremelimumab (11.4% and 12.2%, respectively), and anemia (17.5%) for SoC. Grade ≥3 trAE rates were 10.1%, 16.3%, and 24.2% for durvalumab, durvalumab plus tremelimumab, and SoC, respectively.

CONCLUSION

There were no statistically significant differences in OS for durvalumab or durvalumab plus tremelimumab versus SoC. However, higher survival rates at 12 to 24 months and response rates demonstrate clinical activity for durvalumab.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02369874.

Personalized biomarker-based treatment strategy for patients with squamous cell carcinoma of the head and neck: EORTC position and approach

The molecular landscape of squamous cell carcinoma of the head and the neck (SCCHN) has been characterized and actionable or targetable genomic alterations have been identified. However, targeted therapies have very limited activity in unselected SCCHN, and the current treatment strategy is still based on tumor location and disease stage and not on tumor biology. Trying to select upfront the patients who will benefit from a specific treatment might be a way to improve patients' outcome. With the objective of optimizing the activity of targeted therapies and immunotherapy, we have designed an umbrella biomarker-driven study dedicated to recurrent and/or metastatic SCCHN patients (EORTC-1559-HNCG, NCT03088059). In this article, we review not only the different trial designs for biomarker-driven studies with their respective advantages and opportunities but also the potential pitfalls that led to the design of the EORTC-1559-HNCG protocol. We also discuss the scientific and logistic challenges of biomarker-driven trials.

Difficulties in conducting pure academic research, obstacles in data collection and quality of informations: The example of the INTERCEPTOR study

PURPOSE/OBJECTIVE

On September 2009: We started a randomized multicenter phase III study comparing chemoradiation (CRT) (Aldestein RTOG regimen) versus induction chemotherapy followed by Cetuximab radiation (IBRT). The main study's aim was comparison of overall survival but no formal analyses have been made between the two arms because of low accrual and high amount of missing data. The goal of this paper is to identify the reasons of difference in accrual and quality of data among participating centers.

MATERIAL/METHODS

Statistic: We correlated data collection quality with relevance of the centers, accrual and number of scientific papers (both specific on HNC and other topics) of each PI. We created an HNC publishing score dividing the number of HNC specific papers for the overall number of published papers.

RESULTS

We observed a strong difference in the accrual of pts as well as in the quality of data among the participating centers. The accrual was independent from the quality of data since some centers with low accrual produced high quality data with an excellent follow up. We found a correlation among both number of published papers of each PI and HNC publishing score with the quality of data.

CONCLUSION

The study demonstrated that expertise in HNC is important not only to ensure a better outcomes but also to provide high quality data in phase III trials.

Adjuvant androgen deprivation therapy for poor-risk, androgen receptor-positive salivary duct carcinoma

AIM

Salivary duct carcinoma (SDC), an aggressive subtype of salivary gland cancer, is androgen receptor (AR)-positive in 67-96% of cases. In patients with locally recurrent and metastatic (R/M) AR-positive SDC, androgen deprivation therapy (ADT) has an overall response rate of 18-64.7%. In this study, we describe the efficacy of adjuvant ADT in patients with poor-risk (stage 4a) AR-positive SDC.

METHODS

This is a retrospective cohort study in which patients with stage 4a AR-positive SDC were offered adjuvant ADT, i.e. bicalutamide, luteinizing hormone-releasing hormone (LHRH) analogue or a combination of these after tumour resection. In the control group, data were collected on patients with stage 4a SDC who underwent a tumour resection but did not receive adjuvant ADT.

RESULTS

Twenty-two AR-positive SDC patients were treated with adjuvant ADT for a median duration of 12 months. The control group consisted of 111 SDC patients. After a median follow-up of 20 months in the ADT-treated patients and 26 months in the control group, the 3-year disease-free survival (DFS) was estimated as 48.2% (95% confidence interval [CI] 14.0-82.4%) and 27.7% (95% CI 18.5-36.9%) (P = 0.037). Multivariable Cox regression analysis showed a hazard ratio of 0.138 (95% CI 0.025-0.751, P = 0.022) for DFS and 0.064 (95% CI 0.005-0.764, P = 0.030) for overall survival (OS) in favour of the ADT-treated patients.

CONCLUSION

Poor-risk, AR-positive SDC patients who received adjuvant ADT have a significantly longer DFS compared with patients in the control group, who did not receive adjuvant ADT. For OS, this was just below and above the significance level, in case there was or was no correction for confounders.

Evaluation of the impact of tumor HPV status on outcome in patients with locally advanced unresectable head and neck squamous cell carcinoma (HNSCC) receiving cisplatin, 5-fluorouracil with or without docetaxel: a subset analysis of EORTC 24971 study

Background

EORTC 24971 was a phase III trial demonstrating superiority of induction regimen TPF (docetaxel, cisplatin, 5-fluorouracil) over PF (cisplatin/5-fluorouracil), in terms of progression-free (PFS) and overall survival (OS) in locoregionally advanced unresectable head and neck squamous cell carcinomas. We conducted a retrospective analysis of prospectively collected data aiming to evaluate whether only HPV(-) patients (pts) benefit from adding docetaxel to PF, in which case deintensifying induction treatment in HPV(+) pts could be considered.

Patients and methods

Pretherapy tumor biopsies (blocks or slides) were assessed for high-risk HPV by p16 immunohistochemistry, PCR and quantitative PCR. HPV-DNA+ and/or p16+ tumors were subjected to in situ hybridization (ISH) and HPV E6 oncogene expression qRT-PCR analysis. Primary and secondary objectives were to evaluate the value of HPV/p16 status as predictive factor of treatment benefit in terms of PFS and OS. The predictive effect was analyzed based on the model used in the primary analysis of the study with the addition of a treatment by marker interaction term and tested at two-sided 5% significance level.

Results

Of 358, 119 pts had available tumor samples and 58 of them had oropharyngeal cancer. Median follow-up was 8.7 years. Sixteen of 119 (14%) evaluable samples were p16+ and 20 of 79 (25%) evaluable tumors were HPV-DNA+. 13 of 40 pts (33%) assessed with HPV-DNA ISH and 12 of 28 pts (43%) assessed for HPV E6 mRNA were positive. The preplanned analysis showed no statistical evidence of predictive value of HPV/p16 status for PFS (P = 0.287) or OS (P = 0.118).

Conclusions

The incidence of HPV positivity was low in the subset of EORTC 24971 pts analyzed. In this analysis only powered to detect a large treatment by marker interaction, there was no statistical evidence that treatment effect found overall was different in magnitude in HPV(+) or HPV(-) pts. These results do not justify selection of TPF versus PF according to HPV status.

Efficacy and safety of single-agent pan-human epidermal growth factor receptor (HER) inhibitor dacomitinib in locally advanced unresectable or metastatic skin squamous cell cancer

BACKGROUND

In recurrent or metastatic (R/M) skin squamous cell cancer (sSCC) not amenable to radiotherapy (RT) or surgery, chemotherapy (CT) has a palliative intent and limited clinical responses. The role of oral pan-HER inhibitor dacomitinib in this setting was investigated within a clinical trial.

METHODS

Patients with diagnosis of R/M sSCC were treated. Dacomitinib was started at a dose of 30 mg daily (QD) for 15 d, followed by 45 mg QD. Primary end-point was response rate (RR). Tumour samples were analysed through next-generation sequencing using a custom panel targeting 36 genes associated with sSCC.

RESULTS

Forty-two patients (33 men; median age 77 years) were treated. Most (86%) received previous treatments consisting in surgery (86%), RT (50%) and CT (14%). RR was 28% (2% complete response; 26% partial response), disease control rate was 86%. Median progression-free survival and overall survival were 6 and 11 months, respectively. Most patients (93%) experienced at least one adverse event (AE): diarrhoea, skin rash (71% each), fatigue (36%) and mucositis (31%); AEs grade 3-4 occurred in 36% of pts. In 16% of cases, treatment was discontinued because of drug-related toxicity. TP53, NOTCH1/2, KMT2C/D, FAT1 and HER4 were the most frequently mutated genes. BRAF, NRAS and HRAS mutations were more frequent in non-responders, and KMT2C and CASP8 mutations were restricted to this subgroup.

CONCLUSIONS

In sSCC, dacomitinib showed activity similar to what was observed with anti-epidermal growth factor receptor agents, and durable clinical benefit was observed. Safety profile was comparable to previous experiences in other cancers. Molecular pt selection could improve therapeutic ratio.

Treatment of Cancer of the Base of the Tongue and Glosso-Epiglottic Region: A Multicenter Italian Survey

BACKGROUND

The current treatment options for cancer of the base of the tongue and glosso-epiglottic region are surgery, radiotherapy, or a combination of both modalities. Comparisons between different modalities are not common in the literature, and a real standard of treatment has not yet been established. The purpose of our study was to evaluate the results of treatment in a large series of patients from 18 Italian institutions in relation to the main treatment adopted.

METHODS

The present study is a retrospective survey. The series was divided into a combined surgery group and a radiotherapy group. The Kaplan-Meier method and the log-rank test were used for survival calculations and comparisons.

RESULTS

Eight hundred patients were registered (25.7% stage III and 62% stage IV), 336 in the surgery and 372 in the radiotherapy group. Conventional fractionation was adopted in almost all cases. The five-year overall and disease free survival of the whole series was 32% and 38%, respectively. Survival was slightly better for patients with tumors of the glosso-epiglottic region than for those with a tumor of the base of the tongue. Five-year disease-free survival was 55% for patients treated with surgery +/- radiochemotherapy and 26% for those submitted to radiotherapy alone or in combination with chemotherapy. As far as the total dose and the treatment duration were concerned, only 26% of the patients of the radiotherapy group met the established criteria of adequacy, but in patients with adequate radiation the control rate was better only for small tumors (T1-T2).

CONCLUSIONS

The results in patients treated with surgery +/- postoperative radiotherapy were similar to or better than those reported in the best series in the literature. By contrast, the survival rate of irradiated patients was lower than those reported by other centers.

Vismodegib in patients with advanced basal cell carcinoma: Primary analysis of STEVIE, an international, open-label trial

BACKGROUND

The SafeTy Events in VIsmodEgib study (STEVIE, ClinicalTrials.gov, NCT01367665), assessed safety and efficacy of vismodegib-a first-in-class Hedgehog pathway inhibitor demonstrating clinical benefit in advanced basal cell carcinoma (BCC)-in a patient population representative of clinical practice. Primary analysis data are presented.

PATIENTS AND METHODS

Patients with locally advanced or metastatic BCC received oral vismodegib 150 mg/d until progressive disease, unacceptable toxicity, or withdrawal. Primary objective was safety. Efficacy variables were assessed as secondary end-points.

RESULTS

Evaluable adult patients (N = 1215, 1119 locally advanced; 96 metastatic BCC) from 36 countries were treated; 147 patients (12%) remained on study at time of reporting. Median (range) treatment duration was 8.6 (0-44) months. Most patients (98%) had ≥1 treatment-emergent adverse event (TEAE). The incidence of the most common TEAEs was consistent with reports in previous analyses. No association between creatine phosphokinase (CPK) abnormalities and muscle spasm was observed. Serious TEAEs occurred in 289 patients (23.8%). Exposure ≥12 months did not lead to increased incidence or severity of new TEAEs. The majority of the most common TEAEs ongoing at time of treatment discontinuation resolved by 12 months afterwards, regardless of Gorlin syndrome status. Response rates (investigator-assessed) in patients with histologically confirmed measurable baseline disease were 68.5% (95% confidence interval (CI) 65.7-71.3) in patients with locally advanced BCC and 36.9% (95% CI 26.6-48.1) in patients with metastatic BCC.

CONCLUSIONS

The primary analysis of STEVIE demonstrates that vismodegib is tolerable in typical patients in clinical practice; safety profile is consistent with that in previous reports. Long-term exposure was not associated with worsening severity/frequency of TEAEs. Investigator-assessed response rates showed high rate of tumour control. CLINICALTRIALS.GOV: NCT01367665.

A randomized, phase 2 study of cetuximab plus cisplatin with or without paclitaxel for the first-line treatment of patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck

BACKGROUND

B490 (EudraCT# 2011-002564-24) is a randomized, phase 2b, noninferiority study investigating the efficacy and safety of first-line cetuximab plus cisplatin with/without paclitaxel (CetCis versus CetCisPac) in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN).

PATIENTS AND METHODS

Eligible patients had confirmed R/M SCCHN (oral cavity/oropharynx/larynx/hypopharynx/paranasal sinus) and no prior therapy for R/M disease. Cetuximab was administered on day 1 (2-h infusion, 400 mg/m2), then weekly (1-h infusions, 250 mg/m2). Cisplatin was given as a 1-h infusion (CetCis arm: 100 mg/m2; CetCisPac arm: 75 mg/m2) on day 1 of each cycle for a maximum of six cycles. Paclitaxel was administered as a 3-h infusion (175 mg/m2) on day 1 of each cycle. After six cycles, maintenance cetuximab was administered until disease progression or unacceptable toxicity. The primary end point was progression-free survival (PFS). We assumed a noninferiority margin of 1.40 as compatible with efficacy.

RESULTS

A total of 201 patients were randomized 1 : 1 to each regimen; 191 were assessable. PFS with CetCis (median, 6 months) was noninferior to PFS with CetCisPac (median, 7 months) [HR for CetCis versus CetCisPac 0.99; 95% CI: 0.72-1.36, P = 0.906; margin of noninferiority (90% CI of 1.4) not reached]. Median overall survival was 13 versus 11 months (HR = 0.77; 95% CI: 0.53-1.11, P = 0.117). The overall response rates were 41.8% versus 51.7%, respectively (OR = 0.69; 95% CI: 0.38-1.20, P = 0.181). Grade ≥3 adverse event rates were 76% and 73% for CetCis versus CetCisPac, respectively, while grade 4 toxicities were lower in the two-drug versus three-drug arm (14% versus 33%, P = 0.015). No toxic death or sepsis were reported and cardiac events were negligible (1%).

CONCLUSION

The two-drug CetCis regimen proved to be noninferior in PFS to a three-drug combination with CetCisPac. The median OS of both regimens is comparable with that observed in EXTREME, while the life-threatening toxicity rate appeared reduced.

CLINICAL TRIAL NUMBER

EudraCT# 2011-002564-24.

Overall survival analysis of EXAM, a phase III trial of cabozantinib in patients with radiographically progressive medullary thyroid carcinoma

BACKGROUND

Primary analysis of the double-blind, phase III Efficacy of XL184 (Cabozantinib) in Advanced Medullary Thyroid Cancer (EXAM) trial demonstrated significant improvement in progression-free survival with cabozantinib versus placebo in patients with progressive medullary thyroid cancer (MTC). Final analysis of overall survival (OS), a key secondary endpoint, was carried out after long-term follow-up.

PATIENTS AND METHODS

EXAM compared cabozantinib with placebo in 330 patients with documented radiographic progression of metastatic MTC. Patients were randomized (2:1) to cabozantinib (140 mg/day) or placebo. Final OS and updated safety data are reported.

RESULTS

Minimum follow-up was 42 months. Kaplan-Meier analysis showed a 5.5-month increase in median OS with cabozantinib versus placebo (26.6 versus 21.1 months) although the difference did not reach statistical significance [stratified hazard ratio (HR), 0.85; 95% confidence interval (CI), 0.64-1.12; P = 0.24]. In an exploratory assessment of OS, progression-free survival, and objective response rate, cabozantinib appeared to have a larger treatment effect in patients with RET M918T mutation-positive tumors compared with patients not harboring this mutation. For patients with RET M918T-positive disease, median OS was 44.3 months for cabozantinib versus 18.9 months for placebo [HR, 0.60; 95% CI, 0.38-0.94; P = 0.03 (not adjusted for multiple subgroup analyses)], with corresponding values of 20.2 versus 21.5 months (HR, 1.12; 95% CI, 0.70-1.82; P = 0.63) in the RET M918T-negative subgroup. Median treatment duration was 10.8 months with cabozantinib and 3.4 months with placebo. The safety profile for cabozantinib remained consistent with that of the primary analysis.

CONCLUSION

The secondary end point was not met in this final OS analysis from the trial of cabozantinib in patients with metastatic, radiographically progressive MTC. A statistically nonsignificant increase in OS was observed for cabozantinib compared with placebo. Exploratory analyses suggest that patients with RET M918T-positive tumors may experience a greater treatment benefit with cabozantinib.

TRIAL REGISTRATION NUMBER

NCT00704730.