Sometimes in the pharmaceutical world, you do everything right on your end and still get blocked by someone else's problems. That's the situation facing ImmuCell Corporation (ICCC), which just received an Incomplete Letter from the FDA for Re-Tain, its intramammary treatment for subclinical mastitis in lactating dairy cows.
The twist here is particularly frustrating. ImmuCell had crafted what seemed like a smart manufacturing strategy to manage both costs and technical risk. The company produced the active pharmaceutical ingredient using its own proprietary process at its own facility, then contracted out the aseptic syringe filling to an FDA-approved manufacturer specializing in animal health products. Classic make-versus-buy optimization.
When Your Partner Becomes Your Problem
ImmuCell's facility passed FDA inspection in 2024 without issue. But according to the company, the FDA is now declining to approve the New Animal Drug Application because the contract manufacturer hasn't adequately addressed its own inspectional deficiencies. In other words, ImmuCell did its homework, but its partner didn't.
Faced with mounting delays and a contract with the manufacturer set to expire in March 2026, ImmuCell made the call to pause further Re-Tain investment. The company isn't abandoning the product entirely though. It plans to complete ongoing studies to potentially improve the product's claims for preventing and treating mastitis, then seek licensing partners or team up with a global manufacturer depending on those results.
Pivoting to First Defense
Rather than sink more resources into the Re-Tain bottleneck, ImmuCell is redirecting capital toward its First Defense franchise. The company is expanding its First Defense sales force by 50% and increasing manufacturing capabilities for that product line.
This strategic shift comes with a price tag. ImmuCell expects to record a non-cash impairment write-down during the fourth quarter of 2025. The company disclosed that Re-Tain assets had a net book value of approximately $15.5 million as of September 30, 2025. After adjustments to laboratory and manufacturing equipment and construction in progress, the estimated non-cash hit to profit should land around $2.3 million.
ImmuCell shares rose 1.73% to $5.90 in premarket trading on Friday.




