▶ Watch Video: New report finds colorectal cancer rising among U.S. adults under 55

Pluvicto, a drug used to treat advanced prostate cancer, is in short supply, the Food and Drug Administration reported last week.

Novartis, the pharmaceutical company that manufactures Pluvicto, outlined the causes behind the supply issues in a letter posted by the FDA last month.

In the letter, the company said that it currently only manufactures Pluvicto in Italy in “small batches,” and is awaiting FDA approval on a new manufacturing site. That approval was expected to come in four to six months, Novartis said. 

“We are operating our production site at full capacity to treat as many patients as possible, as quickly as possible.” the company said. “However, with a nuclear medicine like Pluvicto, there is no back-up supply that we can draw from when we experience a delay.”

Novartis said that any issues caused by weather or “unplanned manufacturing events” can cause delays. The company noted there is only a “five-day window” for the drug to reach the patient once its manufactured. 

When shipments of Pluvicto are delayed, or it has have to be remade, it creates a domino effect, the letter noted. 

The company said it is currently prioritizing “patients who have received their first doses and are currently in the treatment process.” 

Novartis said it will not take any new orders until there is “clarity on the FDA’s approval” of its new manufacturing facility. 

Company spokesperson Julie Masow told The Wall Street Journal Thursday that Novartis is seeking FDA approval for manufacturing commercial Pluvicto at its site in Millburn, New Jersey.

“Our ability to supply Pluvicto with only one approved site is presenting significant challenges, and we are working around the clock to generate as much supply as possible,” she told the Journal.

The FDA approved Pluvicto as a treatment for prostate cancer back in March of 2022. 

According to numbers from the American Cancer Society, aside from skin cancer, prostate cancer is the most common cancer in American men, and about one in eight men will be diagnosed with prostate cancer during their lifetime.

Most men diagnosed with prostate cancer do not die from the disease, the organization said.