The lag time in initiating clinical testing of new drugs in combination with radiation therapy, a significant barrier to progress?

P. Blumenfeld, R. M. Pfeffer, Z. Symon, R. B. Den, A. P. Dicker, D. Raben, Y. R. Lawrence*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Background:The clinical development of new drugs with radiation appears to be limited. We hypothesised that phase I clinical trials with radiation therapy (RT) are initiated too late into a new drug's lifetime, impeding the ability to complete RT-drug development programmes before patent expiration.Methods:We identified novel drug-radiation phase I combination trials performed between 1980 and 2012 within the PubMed and databases. Data gathered for each drug included: date the initial phase I trial with/without RT was opened/published, date of the published positive phase III trials, and patent expiration dates. Lag time was defined as the interval between opening of the phase I trial without RT and the opening of the phase I with RT. Linear regression was used to model how the lag time has changed over time.Results:The median lag time was 6 years. The initial phase I trial with RT was typically published 2 years after the first published positive phase III trial and 11 years before patent expiration. Using a best-fit linear model, lag time decreased from 10 years for phase I trials published in 1990 to 5 years in 2005 (slope significantly non-zero, P<0.001).Conclusions:Clinical drug development with RT commences late in the life cycle of anti-cancer agents. Taking into account the additional time required for late-phase clinical trials, the delay in initiating clinical testing of drug-RT combinations discourages drug companies from further pursuing RT-based development. Encouragingly, lag time appears to be decreasing. Further reduction in lag time may accelerate RT-based drug development, potentially improving patient outcomes.

Original languageEnglish
Pages (from-to)1305-1309
Number of pages5
JournalBritish Journal of Cancer
Issue number7
StatePublished - 23 Sep 2014


FundersFunder number
National Cancer Institute


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