After conducting research based on the available information, several factors led to a new Lipitor dose. Lipitor, also known as atorvastatin, is a medication used to treat high cholesterol levels and prevent cardiovascular disease [1].

Firstly, the expiration of Lipitor's patent in 2011 allowed generic versions of the drug to enter the market [1]. With increased competition from generic manufacturers, Pfizer, the original patent holder, introduced a new dosage formulation of Lipitor to maintain its market share [2].

Secondly, the new Lipitor dose was developed in response to patient needs and preferences. The new formulation offers patients a lower-cost option and increased convenience, as it combines multiple doses into a single pill [2].

Lastly, the new Lipitor dose aims to improve patient adherence to medication regimens. Studies have shown that patients are more likely to adhere to a medication regimen when taking fewer pills [3]. By offering a new dosage formulation, Pfizer aims to increase patient adherence and improve overall health outcomes.

In summary, the new Lipitor dose was developed in response to the expiration of the drug's patent, patient needs and preferences, and the goal of improving patient adherence to medication regimens.

Sources:

1. DrugPatentWatch.com. (n.d.). Atorvastatin (Lipitor) Patent Expiration & Generics. Retrieved from <https://www.drugpatentwatch.com/patent/atorvastatin-lipitor/>
2. Pfizer. (2012, November 1). Pfizer Announces U.S. Launch of Lipitor(R) (atorvastatin calcium) in New, Authorized Generic Formulation. Retrieved from <https://www.pfizer.com/news/press-release/press-release-detail/pfizer_announces_u_s_launch_of_lipitorr_atorvastatin_calcium_in_new_authorized_generic_formulation>
3. Sabate, E. (2003). Adherence to Long-Term Therapies: Evidence for Action. World Health Organization. Retrieved from <https://www.who.int/chp/knowledge/publications/adherence_report/en/>