The Regulatory Challenges of Drug-induced Phospholipidosis
This is an FDA presentation from April 14, 2010 that is an Advisory Committee publication because phospholipidosis (PLD) has been seen increasingly in preclinical safety studies since the late 1940s when it was first seen in a two-year rat study of chloroquin (the antimalaria drug). The publications states:
Two important points on page 9 of the presentation:
1. Phospholipidosis is an adaptive response
by the host in response to the presence of a drug, rather than a toxic manifestation.
2. Phospholipidosis that is seen in animals is not predictive of similar findings clinically." (Meaning in humans or animals where the product is actually treating a disease and is bioassimilated)
The slide on page 10 is more to the point:
"What have we learned about PLD-inducing drugs?
• Associated with every pharmacological class.
• Not always associated with toxicity in preclinical studies.
• No direct association with clinical outcome regarding structural pathology or functional toxicity.
• Most of PLD inducing drugs are cationic amphiphilic drugs (CADs)."
This entire thread of speculation is probably total BS. The point above that "every pharmacological class" of drug can have this finding associated with a preclinical safety study is where the buck stops. My only hope is that the dog inhalation study has a withdrawl group that is evaluated 3 months after the last inhalational dose of Arikace or Placebo. What that will likely show is a diminished number or no foamy macrophages.