Novartis (NYSE:NVS) announced that it had voluntarily stopped the production at radioligand therapy plants in Ivrea, Italy and Millburn, New Jersey, over possible quality concerns.

In a statement, the company explained it had made the decision “out of an abundance of caution due to potential quality issues identified in its manufacturing processes.”

As a result, it will stop the distribution of Lutathera (USAN: lutetium Lu 177 dotatate; INN: lutetium (177Lu) oxodotreotide in the U.S. and Canada, and Pluvicto (lutetium Lu 177 vipivotide tetraxetan).

The company plans to investigate further before resuming the production of the two radioligand therapies.

The company anticipates having some supply of the two drugs in the next six weeks.

In the meantime, the company can continue distributing Lutathera in Europe and Asia from a site in Zaragoza, Spain. Novartis, however, acknowledges that the supply of the drugs may be limited.

The company will also place a temporary hold on screening and enrollment for international clinical trials involving 177Lu-PSMA-617 and Lutathera studies in the U.S. and Canada.

NVS shares fell 0.45% to $85.82 on Friday.

FDA approved Lutathera for gastroenteropancreatic neuroendocrine tumors in 2018.

Pluvicto became FDA approved in March 2022 as a treatment for progressive, PSMA-positive metastatic castration-resistant prostate cancer.