83 TWENTYFOURSEVENBIOPHARMA Issue 3 / October 2025 ADRAGOS PHARMA that need to be made at the outset on the design, and this will include the number of participants, and the administration conditions of the drug – will it be taken by the subject under fasting or fed conditions? Additionally, there is the choice as to whether it will be a simple crossover study, or would it be advantageous to have a replicate design. In a standard crossover study, each participant receives the test and reference formulations once each; in a replicate crossover design, each participant typically receives each formulation twice. Experience in design is crucial when deciding which studies are required to achieve approval. There are various factors that must be taken into account, for example, if the marketed drug is sold at multiple dosage strengths, will a study using just the highest dose suffice, or will a range of doses need to be investigated? Additionally, if a single study in fasted patients is undertaken, is it necessary to also run studies under fed or steady state conditions? Conducting a bioequivalence trials A typical pivotal study for a simple protocol includes 24–32 participants. However, in some cases up to 100 participants may be required, and studies with as many as 200 participants have been reported to demonstrate that the two products have comparable bioavailability. Subjects will be given either the originator or the generic, often after having to fast overnight, and then blood samples will be taken at specified time intervals. These samples are then analysed, and parameters such as the area under the concentration–time curve (AUC), which indicates the extent of absorption, and C max (maximum concentration), an indicator of the absorption rate, are calculated. If the figures are similar, then the products are deemed bioequivalent. The process is similar for all small molecule drugs that are administered orally, whether the dosage form is tablet, capsule, or liquid. A topical product such as a cream or ointment may follow a similar bioequivalence process, however in such cases, the data points of interest may change from systemic absorption levels to local absorption at the site of application. For topical drugs, parameters such as skin penetration and local drug concentration may be measured to determine equivalence. Integrated study partners Many of the parts of a study design will use service companies, and there is potential to use numerous for different aspects. These include analytical laboratory studies, protocol design, study formulation design and manufacture, and reporting. It is advantageous in terms of speed, cost and communication to use an integrated partner that has the capabilities to manage and oversee the entire process. Acting as a single project manager, the partner can coordinate all activities and liaise with the customer to ensure timelines and costs are being adhered to, and the study has the greatest chance of success. If third-party contractors are necessary for any steps, then the project manager can be responsible for these too, reducing the burden on the customer. With one provider, the project manager can ensure all paperwork is carried out properly and prepared for the marketing authorisation application, and will have direct access to all contributors to reduce the administration. The timescale involved in such a study can vary greatly, depending on the complexity of the project. It can typically take between six and nine months to design a suitable dosage form, and fully evaluate its stability. The GMP manufacturing phase can be prepared during this period, and then started once the initial studies have been completed and validated. Alongside this, the planning of the protocol for the studies can be carried out, so that once material has been manufactured, they can begin – either with a pilot study, or moving directly to the pivotal study. With careful design and preparation, this can often be completed within six months. Overall, the product can progress from conception to submission within 18 months under the guidance of an experienced team. It can typically then take regulators a further 12-18 months to decide whether to approve it or not, making the total timescale for such a project three years. With more complex generic products, this may be longer; however, it is significantly shorter than for a new chemical entity, where the process takes a decade or more, involving multiple phases of clinical trials. Market entry and regulatory considerations A generic product generally cannot be approved or marketed until applicable regulatory exclusivities have expired and any relevant patents have expired, been invalidated, or licensed. Development and testing can proceed while these protections are in force under “Bolar” (safeharbour) provisions. In the United States, protection comes from both patents and regulatory exclusivities: new chemical entities
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