The FDA ( U.S. Food and Drug Administration ) has granted approval to Turalio ( Pexidartinib ) capsules for the treatment of adult patients with symptomatic tenosynovial giant cell tumor ( TGCT ) associated with severe morbidity or functional limitations and not responsive to improvement with surgery.
Tenosynovial giant cell tumor can cause debilitating symptoms for patients such as pain, stiffness and limitation of movement.
The tumor can significantly affect a patient’s quality of life and cause severe disability.
Surgery is the primary treatment option, but some patients are not eligible for surgery, and tumors can recur, even after the procedure.
The approval of Turalio is the first FDA-approved therapy to treat this rare disease.
Tenosynovial giant cell tumor is a rare tumor that affects the synovium ( thin layer of tissue that covers the surfaces of the joint spaces ) and tendon sheaths ( layer of membrane that covers tendons, which are fibrous tissue that connect muscle to bone ).
The tumor is rarely malignant but causes the synovium and tendon sheaths to thicken and overgrow, causing damage to surrounding tissue.
The approval of Turalio was based on the results of a multi-center international clinical trial of 120 patients, 59 of whom received placebo.
The primary efficacy endpoint was the overall response rate ( ORR ) analyzed after 25 weeks of treatment.
The clinical trial has demonstrated a statistically significant improvement in ORR in patients who received Turalio, with an ORR of 38%, compared to no responses in patients who received placebo.
The complete response rate was 15% and the partial response rate was 23%.
A total of 22 out of 23 responders who had been followed for a minimum of six months following the initial response maintained their response for six or more months, and a total of 13 out of 13 responders who had been followed for a minimum of 12 months following the initial response maintained their response for 12 or more months.
The prescribing information for Turalio includes a Boxed Warning to advise health care professionals and patients about the risk of serious and potentially fatal liver injury.
Health care professionals should monitor liver tests prior to beginning treatment and at specified intervals during treatment.
If liver tests become abnormal, Turalio may need to be withheld, the dose reduced, or permanently discontinued, depending on the severity of the liver injury.
Turalio is available only through the Turalio Risk Evaluation and Mitigation Strategy ( REMS ) Program.
Common side effects for patients taking Turalio were increased lactate dehydrogenase, increased aspartate aminotransferase, loss of hair color, increased alanine aminotransferase and increased cholesterol.
Additional side effects included neutropenia, increased alkaline phosphatase, decreased lymphocytes, eye edema, decreased hemoglobin, rash, dysgeusia and decreased phosphate.
The FDA has advised health care professionals to tell females of reproductive age and males with a female partner of reproductive potential to use effective contraception during treatment with Turalio.
Women who are pregnant or breastfeeding should not take Turalio because it may cause harm to a developing fetus or newborn baby.
The FDA granted this application Breakthrough Therapy designation and Priority Review designation.
Turalio has also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases. ( Xagena )
Source: FDA, 2019