Erlotinib for advanced hepatocellular carcinoma
===============================================

* Jing Zhang
* Yuan Zong
* Gang-Zhu Xu
* Ke Xing

## A systematic review of phase II/III clinical trials

## Abstract

**Objectives:** To evaluate the efficacy and safety of erlotinib for the treatment of advanced hepatocellular carcinoma (HCC).

**Methods:** A systematic literature search was undertaken in June 2015. Phase II/III trials of erlotinib for the treatment of advanced HCC were included. A descriptive analysis was applied. The study was conducted in College of Medicine, Honghui Hospital, Xi’an Jiaotong University, Xi’an, China, between June 2015 and January 2016.

**Results:** Ten trials, comprising 9 phase II and one phase III trial, were included in the systematic review. The tumor response rate was 0% in 4 of the phase II trials, <10% in 3 of the phase II trials and the phase III trial, and >20% in 2 of the phase II trials. The disease control rate was 42.5-79.6% in most studies. Three studies reported a median progression-free survival (PFS) of 6.5-9.0 months, although PFS was <3.5 months in most studies. Most trials reported a median overall survival of 6.25-15.65 months. The most frequent grade 3/4 toxicities were fatigue (11.9%), diarrhea (10%), increased alanine and aspartate transaminases (7.3%), and rash/desquamation (6.9%).

**Conclusion:** Erlotinib provides efficacious and well-tolerated treatment for advanced HCC. However, more detailed investigations of HCC pathogenesis and evaluation of sensitive patient subsets are needed to improve outcomes of patients with advanced HCC. Additional well-designed, randomized, controlled trials are needed to evaluate the efficacy and safety of erlotinib as monotherapy or combination with other drugs for advanced HCC.

Globally, hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor in adults and the third-most frequent cause of cancer-induced mortality.1,2 Because early-stage HCC typically has no symptoms and monitoring is infrequently performed, most patients with HCC are diagnosed at an advanced or unresectable stage.3 For advanced or unresectable HCC, the treatment options are few, and therapeutic outcome is poor.4 Erlotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is orally bioavailable. Erlotinib can inhibit proliferation, invasion, metastasis, and angiogenesis in tumor cells.5,6 Some clinical trials have evaluated erlotinib for the management for advanced HCC,7-11 but these studies are compromised by having small and underpowered sample sizes. There is no comprehensive summary of these trials; therefore, the true impact of erlotinib on advanced HCC is unknown. We conducted a systematic literature review of the currently available data to obtain a full overview of the efficacy and safety of erlotinib for the treatment of advanced HCC.

## Methods

### Search strategy

In June 2015, we systematically searched the Cochrane Library database, the World Health Organization trial registry, clinicaltrials.gov, MEDLINE, and EMBASE without language or year restrictions. We used the following search terms: “Erlotinib”, “Tarceva”, “OSI-774”, “hepatocellular carcinoma OR hepatoma OR liver cell carcinoma OR hepatocellular cancer”, and “unresectable OR advanced”. The bibliographies of all eligible articles and related reviews were searched manually to retrieve any additional relevant articles not discovered by electronic searches.

### Inclusion and exclusion criteria

We included any articles that reported phase II/III trials of erlotinib for the treatment of unresectable or advanced HCC. The exclusion criteria were animal studies and meeting abstracts that did not report data for the outcomes of interest. Two independent reviewers initially screened and excluded studies based on the titles and abstracts. The remaining publications were scrutinized for relevant outcomes of interest.

### Study design

A systematic literature review of phase II/III trials of erlotinib for the treatment of unresectable or advanced HCC was performed.

### Outcome measures

Based on the National Cancer Institute Common Terminology Criteria (version 2.0) and Response Evaluation Criteria in Solid Tumors (RECIST version 1.0) criteria, tumor responses and toxicities were assessed.

### Data extraction

Data extraction was performed and cross-checked independently by 2 reviewers using a standard data extraction form. Any discrepancies were determined by consensus with involvement of the third investigator if necessary. The following data were extracted when available: detailed information regarding erlotinib, including dosages, treatment regimen, number of cycles, and line of treatment; response evaluation, including complete response rate (CR), partial response rate (PR), progressive disease rate (PD), stable disease rate (SD), in addition to 2 indirect index: response rate (RR, CR + PR), and disease control rate (DCR, CR + PR + SD); prognosis, including progression-free survival (PFS), time-to-progression (TTP), overall survival (OS); and the incidence of toxicities.

### Statistical analysis

We planned to combine suitable data to calculate the risk ratios with 95% confidence intervals for dichotomized variables and the weighted mean difference for continuous variables. A meta-analysis was planned using Review Manager (The Cochrane Collaboration, Version 5.2). If it proved impossible to combine the data for analysis, as an alternative, a descriptive analysis would be employed.

## Results

### Study characteristics

The process of study selection is shown in **Figure 1**. Ultimately, 10 trials were included in the present systematic review.7-16 The basic characteristics of the included trials are shown in **Table 1**. Inter-study heterogeneity in the different inclusion and exclusion criteria, the differences in drug combinations, and dosages and treatment regimens precluded a meta-analysis to compare the efficacy and safety of erlotinib versus control treatment. Furthermore, most trails were single-arm and phase II trials without a control arm, except one phase III randomized controlled trial (RCT), preventing us from conducting a meta-analysis. Therefore, the findings of this study are reported using a descriptive analysis.

![Figure 1](http://smj.org.sa/https://smj.org.sa/content/smj/37/11/1184/F1.medium.gif)

[Figure 1](http://smj.org.sa/content/37/11/1184/F1)

Figure 1 
Study selection process for the systematic review of phase II/III trials of erlotinib for the treatment of unresectable or advanced hepatocellular carcinoma.

View this table:
[Table 1](http://smj.org.sa/content/37/11/1184/T1)

Table 1 
Basic characteristics of included studies in systematic review of phase II/III trials of erlotinib for the treatment of unresectable or advanced hepatocellular carcinoma.

### Tumor response

Tumor RR and PR rates were 0-25.0%. Four of the phase II trials reported a 0% tumor RR,8,12,13,15 while <10% was reported in 3 of the phase II trials and the phase III trial,7,11,14,16 and >20% in 2 of the phase II trials (**Table 2**).9,10 There were no CRs in the phase II trials, but 2 (0.6%) patients showed a CR in the phase III RCT.16 In most trials, 40-50% of patients had SD after erlotinib treatment.7,11,14,15

View this table:
[Table 2](http://smj.org.sa/content/37/11/1184/T2)

Table 2 
Efficacy of studies included in systemic review of phase II/III trials of erlotinib for the treatment of unresectable or advanced hepatocellular carcinoma.

### Disease control rate

The DCR was 42.5-79.6% in most studies. The DCR in 4 phase II trials was 50-80%,7,9,10,14 and the DCR in 3 phase II trials and the phase III RCT was 40-50% (**Table 2**).8,11,15,16 For the remaining phase II trials, one reported a DCR of 28%,13 whereas the other reported a DCR of 0%.12

### Progression-free survival/time-to-progression

The median PFS or TTP in all studies was 1.81-9.0 months. Three of the included studies reported a median PFS of 6.5-9.0 months,8-10 but most reported a PFS of <3.5 months (**Table 2**).7,11-16

### Overall survival

The median OS in all studies was 4.37-15.65 months. Nine of the 10 trials reported a median OS of 6.25-15.65 months,7-11,13-16 except one phase II trial that reported an OS of 4.37 months (**Table 2**).12

### Toxicities

The phase II trials of Thomas et al9 and Kaseb et al10 were performed in the same institution, and the latter sample (n=59) included that of the former (n=40). Therefore, we included only the study of Kaseb et al10 during toxicity analysis. In addition, due to the differences in the study types, we did not combine the phase III RCT data with the phase II study data. Eventually, the toxicity was assessed using the data combined from 8 phase II trials (n=260).7,8,10-15

The most typical reported toxicities, experienced by ≥20% of patients, regardless of grade, were diarrhea (57.3%), rash/desquamation (55.4%), fatigue (46.2%), nausea (26.9%), dry skin (26.9%), acne (26.9%), anorexia (26.5%), increased alanine and aspartate transaminases (22.7%), and epistaxis (21.5%). Grade 1 and grade 2 toxicities were most frequently reported. Within grade 3/4 toxicities, those that occurred in more than 5% of patients were fatigue (11.9%), diarrhea (10%), increased alanine and aspartate transaminases (7.3%), and rash/desquamation (6.9%). For the phase III trial,16 the overall rates of emergent adverse events (AEs) (100% versus 99.2%) and drug-related AEs (95.0% versus 95.2%) were similar between the sorafenib plus erlotinib and sorafenib plus placebo groups.

In the phase II studies, 2 patients died: one due to complications after experiencing gastrointestinal hemorrhage,9 and one due to acute respiratory failure caused by pneumonia that was deemed unrelated to the study drugs.11 In the phase III RCT, the frequency of emergent AEs leading to death was similar between the arms; 72 (20.3%) patients in the sorafenib plus placebo group and 80 (22.1%) patients in the sorafenib plus erlotinib group died of grade 5 emergent AEs.16

Adverse reactions led to 5 (13%) patients withdrawing from a phase II trial, but the details of their adverse reactions were unclear.7 In another phase II study,9 7 (17.5%) patients withdrew due to fatigue, proteinuria, delayed wound healing, and gastrointestinal hemorrhage. One phase II study10 reported that 6 (10%) patients were excluded owing to grade 3-4 gastrointestinal hemorrhage. In the remaining phase II studies,8,11-15 there were no toxicity-related withdrawals. In the phase III RCT,16 the incidence of emergent AEs resulting in withdrawal was similar in the sorafenib plus erlotinib (45.0%) and sorafenib plus placebo (45.6%) groups.

## Discussion

This systematic review provides a comprehensive overview of the current evidence of the efficacy and safety of erlotinib for the treatment of advanced HCC. Although it was impossible to perform an overall meta-analysis for several reasons, in general, the results reported in these studies demonstrate that erlotinib is efficacious and well-tolerated in the treatment of advanced HCC.

When used as monotherapy, the DCR of erlotinib for advanced HCC was good, but the RR was poor,7,8 suggesting that erlotinib alone exhibited modest antitumor activity. However, the promising DCR, TTP, and OS rates in these studies encouraged clinicians to explore the use of erlotinib in conjunction with other anticancer therapies. For example, erlotinib was administered in combination with bevacizumab in 6 phase II trials;9-14 among these 6 trials, 4 phase II trials were included in another systematic review on bevacizumab performed by Fang et al.17 Erlotinib has also been combined with docetaxel in another study,15 and with sorafenib in a phase III RCT.16 Only 2 studies,9,10 with overlapping study populations, showed superior RRs for the combination of bevacizumab with erlotinib when compared with erlotinib monotherapy.7,8 However, other drug combinations did not show any significant benefits for RR.11-16 Most of the drug combinations9-11,14-16 showed similar or slightly better DCRs compared with erlotinib monotherapy,7,8 except for the combinations used in the study by Govindarajan et al12 and Yau et al,13 both of which utilized bevacizumab. All combined therapy studies, except one with bevacizumab,12 demonstrated similar or slightly improved PFS/TTP and OS rates compared with erlotinib monotherapy.7,8

None of the trials reported any unexpected toxicities, and most were grade 1 or 2 in severity. In the phase II studies, there were only 2 patient deaths; one was due to pneumonia11 and deemed unrelated to treatment, and the other was due to gastrointestinal bleeding that occurred during study, but whether it was treatment-related was not disclosed.9 Overall, the number of withdrawals due to AEs was low. In the phase III RCT, the difference in the death or withdrawal rates between the 2 study groups was not significant, suggesting that most were related to sorafenib rather than erlotinib.16 Therefore, the safety analysis in these reports suggested that erlotinib was safe and well-tolerated.

Although sorafenib is the only approved standard treatment for advanced HCC, the survival benefit is relatively modest according to 2 studies.18,19 In the SHARP trial,18 the DCR and median OS rates were 43% and 10.7 months, and in the Asia-Pacific region phase III RCT, they were 35.3% and 6.5 months.19 Overall, the effect of erlotinib for the treatment of advanced HCC in all the trials evaluated in this present study, except for that of Yau et al,12 is comparable with that of sorafenib.18,19 Yau et al12 reported that none of their enrolled 10 patients, who were resistant to sorafenib, responded to the therapeutic combination of erlotinib and bevacizumab. This conclusion suggested that patients who were resistant to sorafenib would not obtain any clinical benefit from treatment with erlotinib or bevacizumab, and the trial was terminated early due to poor patient response. For this reason, the data from that study should be interpreted with caution. However, Kaseb et al10 indicated that PFS and OS in response to erlotinib plus bevacizumab were shorter in those previously treated with sorafenib (PFS of 6.7 months and OS of 9.6 months) when compared with treatment-naive patients (PFS of 7.4 months and OS of 15.0 months). This might suggest further that in sorafenib non-responders, erlotinib plus bevacizumab may not be an appropriate treatment regimen.

Sorafenib can block vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) receptor signaling,20,21 whereas erlotinib blocks EGFR signaling;6 it was hoped that the combination might have a synergistic anticancer effect. Because the combination of erlotinib and sorafenib showed promising antitumor efficacy in a phase I trial,22 and erlotinib showed moderate efficacy in phase II studies,7,8 phase II trials were skipped and a phase III trial was performed directly. Finally, this combination provided no synergistic benefit.16 In this study, we used SEARCH trial,16 erlotinib plus sorafenib as a first-line treatment in advanced HCC patients had similar OS (*p*=0.408) and TTP (*p*=0.18) outcomes compared with placebo plus sorafenib. Possible reasons for the failure of this trial to produce any meaningful effect in advanced HCC patients might be explained by the findings of a study conducted by Sieghart et al23 in a rat model of HCC. Sieghart et al23 found that treatment with erlotinib and sorafenib was not superior to the effect of sorafenib alone in vitro or in vivo, suggesting a lack of any synergistic or additive effect between the 2 drugs. However, they also suggested that erlotinib-induced VEGF expression might have contributed to the failure of the combination therapy.23 This trial demonstrates that we should perform research systematically following the study-design strategy guidelines, instead of carry out large-scale phase III trials without a clear signal of efficacy from earlier-phase studies.

HCC trials are characterized by study population heterogeneity and are, therefore, complex to interpret and dissect.18 Drugs that target all HCC subtypes will need to be explored, and there is room for such drugs, especially for the second-line or third-line treatments. There is an intensive requirement for valid biomarkers to enable selection of suitable subgroups of HCC patients who would be more likely to achieve an objective response to specific anticancer agents.24 For example, erlotinib efficacy is affected by the T790M mutation in the EGFR kinase in non-small-cell lung cancer.25 Therefore, such cases should encourage analogous studies with biomarkers to predict erlotinib efficacy in future phase III trials.

Moreover, sample augmentation or incorporation of a control arm in phase II studies would reduce selection bias and decrease the risk of random effects to obtain an impartial comparison for outcome analysis.18,26 These approaches might reduce the possibility of negative outcomes for future phase III trials.

In all of the included trails, except 2 trails,9,10 the objective response rate was low, but it may be inappropriate to apply this extremely stringent parameter. As alternative endpoints in these studies, DCR, PFS/TTP, and OS have thus been adopted. However, DCR, PFS/TTP, and OS are endpoints that reflect not only treatment effect but also tumor behavior.27 Perhaps it would be better to use primary endpoints to measure the treatment effect of erlotinib.

All of the previous observations remind us to optimize the design of trails, augment sample size, select sensitive subset populations, and use better primary endpoints in order to improve the therapeutic effect in patients with advanced HCC.

There are some limitations in the present systematic review. First, publication bias may affect this area of study and research. In this systematic review, data for one study15 were derived from an abstract because the full-text publication could not be identified, preventing a more in-depth analysis. Second, heterogeneity among trials could affect the validity of the present results. Only one study was an RCT, and most of phase II studies had no head-to-head comparisons. Furthermore, heterogeneity may exist owing to the differences in patients’ characteristics, drug dosages, and treatment regimens, which impedes comparisons between studies. Third, there could be discrepancies in the measurement of outcome measures. For example, PFS is frequently confused with TTP,28 and an unequivocal definition of PFS is seldom provided.

In conclusion, these results are encouraging, and suggest that erlotinib may be a relatively efficacious and well-tolerated treatment for advanced HCC. Owing to the small sample size and lack of controls, this conclusion is not definitive. Although the efficacy of erlotinib was not confirmed in the sole phase III trial, it should not be discarded as a possible treatment option and should be evaluated in future. Given the better overall survival observed in most phase II trials and because treatment of advanced HCC remains unstandardized and unsatisfactory, it is worth determining whether erlotinib can be of benefit to patients with advanced HCC. In future studies, further investigation of the underlying pathogenesis of HCC and exploration of sensitive subset populations are warranted to enhance the effect of erlotinib, thereby improving survival outcomes in patients with advanced HCC. Meanwhile, this systematic review has identified the need for more well-designed RCTs to evaluate the efficacy and safety of erlotinib as monotherapy and in combination with other drugs for advanced HCC.

Authorship entitlement

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Available from [www.icmje.org](http://www.icmje.org)

The international Committee of Medical Journal Editors has recommended the following criteria for authorship; these criteria are still appropriate for those journals that distinguish authors from other contributors.

Authorship credit should be based on 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) intellectual content; and 3) final approval of the version to be published. Authors should meet conditions 1, 2, and 3.

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## Acknowledgment

*The authors would like to thank Li-Qiao Ge, Department of Surgery, First Affiliated Hospital of Xi’an Medical University for assistance with this study’s early development, and Dong-Yuan Cao, Stomatological Hospital, Xi’an Jiaotong University Health Science Center, Xi’an, China for providing writing assistance*.

## Footnotes

*   **Disclosure.** Authors have no conflict of interest, and the work was not supported or funded by any drug company.

*   Received July 31, 2016.
*   Accepted August 24, 2016.


*   Copyright: © Saudi Medical Journal

This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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