Fatigue, urination, rash, mouth ulcers, or hepatitis are less frequent effects (experienced by one in one thousand to one in one hundred patients).

Nephrolithiasis, arthralgia, leukopenia, pancreatitis, or allergic reactions may occur, but are rare (less than one in one thousand patients) .

[6] Nelfinavir and simple derivatives have been found to inhibit the production of the virulence factor streptolysin S, a cytolysin produced by the human pathogen Streptococcus pyogenes.

The way Nelfinavir binds the enzyme may be sufficiently unique to reduce cross-resistance[clarification needed] between it and other PIs.

Nelfinavir was developed by Agouron Pharmaceuticals as part of a joint venture with Eli Lilly and Company.

[15] In the United States, about three dozen clinical trials are being conducted (or have been completed) in order to determine whether nelfinavir is effective as a cancer therapeutic agent in humans.

[citation needed] As of April 2022[update], nelfinavir is being studied as a radiosensitizing agent as part of treatment of advanced cervical cancer.