Pharmaceutical industry perspective on combination toxicity studies: Results from an intra-industry survey conducted by IQ DruSafe Leadership Group

Interest in developing combination products to overcome drug resistance and treat complex diseases is growing. However, ambiguity remains around the value of combination toxicity studies to support combination products. Therefore, the IQ* DruSafe Leadership Group surveyed member companies to evaluate industry experience with combination toxicity strategies, study designs and their impact on clinical development. Twenty companies responded, representing 79 combination programs. Combination toxicity studies were performed based on scientific rationale, regulatory agency request, or expected regulatory requirement. Combination toxicity study designs were varied (eg, group numbers, dose selection rationale and endpoints assessed) with no evidence that any one study design was superior. Studies were perceived as adding value when they fulfilled a regulatory requirement; avoided potential development delays; or when new or exaggerated toxicity or pharmacokinetic interactions were identified. Twelve percent of combination toxicity studies impacted clinical trial designs. The decision to conduct and the design of nonclinical combination toxicity studies should be based on sound scientific judgement with proactive engagement with regulatory agencies. Studies are not warranted when sufficient knowledge (eg, expected pharmacology, known mechanism of action, drug disposition, toxicity profile) is available to proceed safely in clinical development.