Treating Iron Deficiency With Ferric Carboxymaltose

What is this patent about?

’369 is related to the field of treating iron deficiency with intravenous (IV) iron carbohydrate complexes, specifically ferric carboxymaltose (FCM). Iron deficiency impairs hemoglobin production, leading to fatigue and other symptoms. While oral iron is the first-line therapy, it often fails due to compliance issues and side effects. High-dose IV iron, like FCM, offers a rapid and effective alternative, but it can lead to side effects like hypophosphatemia (low serum phosphate).

The underlying idea behind ’369 is that FCM treatment, while effective for iron deficiency, can induce an auto-synergistic increase in iFGF23 (intact Fibroblast Growth Factor 23), a hormone that regulates phosphate and vitamin D. This increase can lead to reduced muscle function and increased bone turnover. The invention aims to mitigate these side effects by adjusting the timing and amount of FCM administered, selecting patients less likely to suffer from these side effects, monitoring patients after the first dose, and combining FCM with other drugs.

The claims of ’369 focus on methods of treating iron deficiency with FCM in subjects with a reduced risk for FGF23-mediated side effects. This involves administering a dose of 750mg of elemental iron followed by a further dose of 750mg of elemental iron, or a dose of 1000mg of elemental iron followed by a further dose in the range of 500mg to 1000mg of elemental iron. The claims also cover methods of monitoring subjects after a dose of FCM by measuring blood or urine parameters such as serum phosphate, vitamin D, ionized calcium, PTH, and urinary phosphate excretion to determine eligibility for a further dose. Additionally, the claims encompass methods for identifying subjects with a reduced risk for FGF23-mediated side effects based on these parameters, exclusion criteria, or respiratory capacity.

In practice, the invention involves a multi-faceted approach. First, patients are screened to determine their risk for FGF23-mediated side effects using blood tests, exclusion criteria (e.g., bariatric surgery, obesity, cardiac conditions), and respiratory capacity measurements. If a patient is deemed suitable, they receive an initial dose of FCM. Afterwards, their blood parameters are monitored to assess the impact on phosphate levels and other relevant markers. Based on these measurements, the timing and dosage of subsequent FCM administrations are adjusted to minimize the risk of adverse effects.

The differentiation from prior approaches lies in the recognition of the auto-synergistic effect of FCM on iFGF23 and the resulting clinical consequences. Previous studies considered FCM-associated hypophosphatemia to be transient and clinically irrelevant. ’369 challenges this view by providing methods for identifying at-risk patients, monitoring their response to FCM, and adjusting treatment regimens or using adjunctive therapies (like vitamin D or phosphate supplements) to mitigate the iFGF23-mediated side effects, thus optimizing the benefit-risk profile of FCM therapy. This proactive approach aims to prevent long-term complications like reduced muscle function and increased bone turnover.