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New analysis of data from the phase 2 PEAK study: Impact of post-progression treatments

A further analysis of data from the phase 2 PEAK trial – which compared Vectibix® + FOLFOX vs bevacizumab + FOLFOX – was recently presented at ASCO1.

 

  • The 2014 American Society of Clinical Oncology (ASCO) Annual Meeting was held in Chicago, from 30 May 30 to 3 June 2014

This analysis focused on the outcomes of patients in the two treatment groups receiving post-progression treatment with an anti-VEGF or anti-EGFR monoclonal antibody.

Details regarding the design of the PEAK study and the main results of the wild-type RAS prospective-retrospective analysis can be found in the Key data/PEAK section.

 

PEAK: Outcomes among patients with wild-type RAS receiving post-progression anti-EGFR and anti-VEGF treatment1

In a prospective-retrospective analysis of outcomes in the phase 2 PEAK study, a significantly longer median progression-free survival (PFS) was observed among patients with wild-type RAS mCRC receiving Vectibix® + FOLFOX than in those receiving bevacizumab + FOLFOX (13.0 months vs 9.5 months; HR=0.65 [95% CI: 0.44–0.96], p=0.029).2 Although the median overall survival (OS) was also longer with Vectibix® + FOLFOX, the difference between groups did not achieve statistical significance.

An exploratory analysis of PEAK was done to evaluate OS among patients who received subsequent therapies.1 Note that the results presented are estimations, and no formal hypothesis testing was planned. The primary analysis of PEAK was scheduled to be conducted when approximately 168 PFS events were observed. The OS results presented here are from an additional follow-up approximately 1 year after the last patient enroled, with 130 deaths reported.

The time to subsequent therapy and the numbers of patients receiving subsequent anti-VEGF/anti-EGFR were similar in the Vectibix® + FOLFOX and bevacizumab + FOLFOX treatment groups.1

PEAK: Time to subsequent therapy among patients with wild-type RAS mCRC – Vectibix® + FOLFOX/subsequent anti-VEGF1

PEAK: bar chart of time to subsequent therapy (wild-type RAS mCRC), 1st line Vectibix® + FOLFOX with post-progression anti-VEGF

Adapted from Rivera et al.1

PEAK: Time to subsequent therapy among patients with wild-type RAS mCRC – Bevacizumab + FOLFOX/subsequent anti-EGFR1

PEAK: bar chart of time to subsequent therapy (wild-type RAS mCRC), 1st line bevacizumab + FOLFOX with post-progression anti-EGFR

Adapted from Rivera et al.1

The OS results by subsequent therapy were similar to those observed in the initial analysis of outcomes in patients with wild-type RAS1,2

PEAK: OS among patients with wild-type RAS mCRC overall and in the subgroup receiving subsequent biologic therapy1

PEAK: graphs of OS among patients with wild-type RAS mCRC, overall and in the subgroup receiving post-progression biologic therapy

Adapted from Rivera et al.1 (a) Patients with wild-type RAS mCRC overall and (b) the subgroup of patients with wild-type RAS mCRC receiving subsequent biologic therapy.

Conclusion

In this exploratory analysis of the phase 2 PEAK study conducted in patients with wild-type RAS mCRC, the investigators concluded that median OS was not dependent on the type of subsequent treatment the patients received.1

References

  1. Rivera F et al. J Clin Oncol 2014;32(suppl):5s, abstract 3629 (and poster).
  2. Schwartzberg LS et al. J Clin Oncol 2014;32:2240–2247.
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