Eli Lilly says Mounjaro price will not fall as KwikPen volume is reduced

Eli Lilly said the wholesale price of the weight-loss drug Mounjaro will remain unchanged even after the company introduces a redesigned KwikPen that reduces the amount of leftover solution in each pre-filled pen.

The company said both the initial and modified KwikPen "contain the volume of solution necessary for priming before each injection and the delivery of four doses (one dose given weekly)," and that the pen has been altered only to reduce the amount of medicine that remains after four prescribed doses. Eli Lilly did not disclose the new pen volumes or when the modified devices will be distributed in the U.K.

The announcement comes after Eli Lilly disclosed a planned increase in Mounjaro wholesale prices effective Sept. 1, with the highest-dose pen rising from about £122 to £330 a month and a mid-range 5mg pen rising from roughly £92 to about £180. The company said the modified KwikPen will be made available globally and that while it has been approved in the U.K., timelines for availability there are not yet determined.

Some private users have been salvaging leftover solution from pens, a practice dubbed the "golden dose," by drawing residual fluid into a syringe to create an additional dose beyond the four intended injections. The existing 3ml pens are designed to deliver a fixed dose weekly and to include a small volume of liquid for priming, which is used to expel air bubbles before injection. That priming allowance leaves a small residual volume after the fourth injection in the current design, which some users have sought to extract.

Public-health officials and clinicians have repeatedly warned against attempting to extract additional doses from pens, citing risks of physical injury and infection when patients try to withdraw residual medicine with needles or other devices. Eli Lilly said the modified pen will reduce the amount of leftover medicine but reiterated that both pen designs provide the necessary volume for priming and four doses.

The prospect of reduced leftover volume prompted angry reactions from some users online, who said the change would make the costly drug harder to afford. On social media and discussion forums, users described the decision as a "kick in the teeth" and discussed continuing to attempt to salvage partial doses despite warnings from health authorities. Others expressed concern that a phased rollout could leave patients uncertain whether they would receive older pens with more residual volume or the redesigned pens.

Under National Health Service guidance, Mounjaro prescriptions are generally limited to patients with a body mass index (BMI) over 40 or those with weight-related health conditions such as high blood pressure, type 2 diabetes or obstructive sleep apnoea. Tens of thousands of people are believed to be using the drug privately. Last year health officials announced a phased, 12-year plan to make Mounjaro available on the NHS to eligible patients. A British Medical Journal analysis published after the rollout began in June found that fewer than half of commissioning bodies in England had started prescribing the drug, a discrepancy that has been described as a "postcode lottery" for access.

Weight-related illness is a substantial economic and health burden in the U.K. Health-care officials estimate it costs the economy about £74 billion a year, and U.K. figures show two in three adults are classed as overweight or obese, with average weights having risen by about a stone over the past three decades.

Eli Lilly said the modified KwikPen will be introduced internationally but declined to provide a timetable for U.K. availability. The company maintained that the change was intended to ensure the pen contains the volume required for priming and for the delivery of four weekly doses as prescribed.