Six versus 12 months' adjuvant trastuzumab in patients with HER2-positive early breast cancer: the PERSEPHONE non-inferiority RCT.

BACKGROUND: The addition of adjuvant trastuzumab to chemotherapy has significantly improved outcomes for people with human epidermal growth factor receptor 2 (HER2)-positive, early, potentially curable breast cancer. Twelve months' trastuzumab, tested in registration trials, was adopted as standard adjuvant treatment in 2006. Subsequently, similar outcomes were demonstrated using 9 weeks of trastuzumab. Shorter durations were therefore tested for non-inferiority. OBJECTIVES: To establish whether or not 6 months' adjuvant trastuzumab is non-inferior to 12 months' in the treatment of HER2-positive early breast cancer using a primary end point of 4-year disease-free survival. DESIGN: This was a Phase III randomised controlled non-inferiority trial. SETTING: The setting was 152 NHS hospitals. PARTICIPANTS: A total of 4088 patients with HER2-positive early breast cancer who it was planned would receive both chemotherapy and trastuzumab took part. INTERVENTION: Randomisation (1 : 1) to 6 months' or 12 months' trastuzumab treatment. MAIN OUTCOMES: The primary end point was disease-free survival. The secondary end points were overall survival, cost-effectiveness and cardiac function during treatment with trastuzumab. Assuming a 4-year disease-free survival rate of 80% with 12 months' trastuzumab, 4000 patients were required to demonstrate non-inferiority of 6 months' trastuzumab (5% one-sided significance, 85% power), defining the non-inferiority limit as no worse than 3% below the standard arm. Costs and quality-adjusted life-years were estimated using a within-trial analysis and a lifetime decision-analytic model. RESULTS: Between 4 October 2007 and 31 July 2015, 2045 patients were randomised to 12 months' trastuzumab and 2043 were randomised to 6 months' trastuzumab. Sixty-nine per cent of patients had ER-positive disease; 90% received anthracyclines (49% with taxanes; 41% without taxanes); 10% received taxanes without anthracyclines; 54% received trastuzumab sequentially after chemotherapy; and 85% received adjuvant chemotherapy (58% were node negative). At 6.1 years' median follow-up, with 389 (10%) deaths and 566 (14%) disease-free survival events, the 4-year disease-free survival rates for the 4088 patients were 89.5% (95% confidence interval 88.1% to 90.8%) in the 6-month group and 90.3% (95% confidence interval 88.9% to 91.5%) in the 12-month group (hazard ratio 1.10, 90% confidence interval 0.96 to 1.26; non-inferiority p = 0.01), demonstrating non-inferiority of 6 months' trastuzumab. Congruent results were found for overall survival (non-inferiority p = 0.0003) and landmark analyses 6 months from starting trastuzumab [non-inferiority p = 0.03 (disease-free-survival) and p = 0.006 (overall survival)]. Six months' trastuzumab resulted in fewer patients reporting adverse events of severe grade [365/1929 (19%) vs. 460/1935 (24%) for 12-month patients; p = 0.0003] or stopping early because of cardiotoxicity [61/1977 (3%) vs. 146/1941 (8%) for 12-month patients; p < 0.0001]. Health economic analysis showed that 6 months' trastuzumab resulted in significantly lower lifetime costs than and similar lifetime quality-adjusted life-years to 12 months' trastuzumab, and thus there is a high probability that 6 months' trastuzumab is cost-effective compared with 12 months' trastuzumab. Patient-reported experiences in the trial highlighted fatigue and aches and pains most frequently. LIMITATIONS: The type of chemotherapy and timing of trastuzumab changed during the recruitment phase of the study as standard practice altered. CONCLUSIONS: PERSEPHONE demonstrated that, in the treatment of HER2-positive early breast cancer, 6 months' adjuvant trastuzumab is non-inferior to 12 months'. Six months' treatment resulted in significantly less cardiac toxicity and fewer severe adverse events. FUTURE WORK: Ongoing translational work investigates patient and tumour genetic determinants of toxicity, and trastuzumab efficacy. An individual patient data meta-analysis with PHARE and other trastuzumab duration trials is planned. TRIAL REGISTRATION: Current Controlled Trials ISRCTN52968807, EudraCT 2006-007018-39 and ClinicalTrials.gov NCT00712140. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 40. See the NIHR Journals Library website for further project information.

THE BACKGROUND: There are several different types of breast cancer and some are called 'HER2 positive'. These cancers can often be cured by treatment with chemotherapy and a drug called trastuzumab (also known as Herceptin®; Roche, Basel, Switzerland). Although the first trials of trastuzumab used 12 months treatment, we did not know if less treatment could work as well. A small trial in Finland showed that giving trastuzumab for just 9 weeks was also effective. We know that trastuzumab can have some side effects, including heart problems, so it was important to see if we could reduce the length of treatment time, which is usually 12 months. WHAT DID WE DO?: We wanted to find out if we could treat patients safely with 6 months rather than 12 months of trastuzumab. We carried out a clinical trial called PERSEPHONE, in which over 4000 patients with this type of early breast cancer took part. Half of the patients were given 12 months of trastuzumab and half were given 6 months of trastuzumab. WHAT DID WE FIND?: We found that the two groups of patients had very similar benefit from treatment. At 4 years after diagnosis 90.3% of those who had received 12 months of trastuzumab were alive and free of any breast cancer recurrence, compared with 89.5% of those who had received 6 months. In other words, 125 patients would need to be treated with 12 months' trastuzumab rather than 6 months' trastuzumab for one more person to be alive and cancer-free 4 years from diagnosis. THE SIDE EFFECTS?: Severe side effects of trastuzumab were seen on at least one occasion in 24% of 12-month patients compared with 19% of 6-month patients. More patients receiving 12 months of trastuzumab had to stop trastuzumab early because of heart problems (8% of 12-month patients compared with 3% of 6-month patients). WHAT DOES THIS ALL MEAN?: We have shown that 6 months of trastuzumab has similar outcomes to 12 months in treating patients with HER2-positive early breast cancer but with fewer severe side effects, including heart problems, fewer visits to hospital for patients and significant cost savings for the NHS.

A clinical perspective on escalating or de-escalating adjuvant therapy in HER2+ breast cancer.

Introduction: Patients with early HER2-positive breast cancer (BC) benefit from HER2-targeted systemic therapy. The endorsed standard adjuvant treatment for patients with early HER2-positive breast cancer is chemotherapy plus trastuzumab administered for 1 year. Areas covered: Several trials have investigated modifications of the standard treatment in terms of de-escalation by either shortening the duration or giving less resource-demanding regimens and in terms of escalation by either adding a second anti-HER2 agent or extending the duration of HER2-targeted treatment for more than 12 months. In this perspective, we would offer a comprehensive view of these trials and discuss their findings. Expert commentary: At the current state of knowledge, there are still open questions regarding the management of HER2+ BC patients, such as the most adequate duration of trastuzumab therapy, the optimal chemotherapy regimen that should be combined with trastuzumab, and the addition of a second anti-HER2 agent. Growing evidences suggest that some HER2+ BC patients may not need chemotherapy. If these patients could be recognized upfront, optimal response could potentially be reached with HER2-targeted therapy alone.

Adjuvant trastuzumab duration trials in HER2 positive breast cancer - what results would be practice-changing? Persephone investigator questionnaire prior to primary endpoint results.

BACKGROUND: Twelve months treatment is the current standard of care for adjuvant trastuzumab in patients with HER2 positive early breast cancer however the optimal duration is not known. Persephone is a non-inferiority randomised controlled trial comparing 6- to 12-months of trastuzumab. In this trial there will be a trade-off between a possible small decrease in disease-free survival (DFS) with 6-months and reduced cardiotoxicity and cost. METHODS: A structured questionnaire asked clinicians who had recruited patients into the Persephone trial about their prior beliefs with regards to the clinical effectiveness of trastuzumab and cardiotoxicity profile, in the comparison of 6- and 12-month durations. RESULTS: Fifty-one clinicians from 40 of the 152 Persephone sites completed the questionnaire. 30/50 responders (60%) believed that 6-months trastuzumab would give the same 4-year DFS rate as 12-months trastuzumab, with 21/50 (42%) holding this belief across all breast cancer subsets. In addition, 46/49 responders (94%) reported expecting to change their clinical practice to 6-months, with their prior beliefs (most commonly 85% 4-year DFS rate with 6-months) being greater than their lowest acceptable rate (most commonly 83% 4-year DFS rate with 6-months). Low levels of cardiotoxicity were expected with both 6 and 12-months trastuzumab, with the majority expecting lower levels with 6-months. With increasing hypothesised differences of cardiotoxicity rates between the two durations, significantly lower levels of 4-year DFS with 6-months trastuzumab were deemed acceptable (p < 0.0001). CONCLUSION: Most responders believe that 6-months trastuzumab is adequate, both overall and within each subset of breast cancer, and plan to change their clinical practice if the Persephone results support their prior belief. An individual patient meta-analysis of the duration trials would give greater precision to estimates of the differences in efficacy and toxicity, and adequate statistical power to establish a 2% level of non-inferiority for 6-months adjuvant trastuzumab.