Thalomid (thalidomide) has been associated with an increased risk of second primary malignancies, according to Celgene Inc. and Health Canada. This serious, adverse side effect has been added to the drug’s Product Monograph.
Thalomid is an immunomodulatory agent indicated for the treatment of patients who are 65 years of age or older and with a previously untreated multiple myeloma. Thalomid is prescribed in combination with melphalan and prednisone (MPT).
The Canadian Product Monograph safety information was updated to include that:
- Second primary malignancies—specifically, acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS)—have been seen in an ongoing clinical trial in patients with previously untreated multiple myeloma who were receiving MPT. AML and MDS have been rarely reported in the post-market setting.
- The risk of AML and MDS must be considered before starting treatment with Thalomid in the MPT combination. Physicians should carefully evaluate patients before and during treatment using standard cancer screening for occurrence of second primary malignancies.
Thalomid’s Canadian Product Monograph has been revised to include the updated risk information within the “Warnings and Precautions” and “Consumer Information” sections.
The revised information was added following a detailed review of the ongoing MM-020 clinical study and prompted by observation of an imbalance in hematologic second primary malignancies (AML/MDS). The review of this ongoing study revealed a statistically significant increase in the risk of AML/MDS in patients with previously untreated multiple myeloma receiving MPT (1.8 percent) following about 22.3 months of observation and when compared to other treatment. Thalomid’s risk increased over time to about 2 percent after two years and to 4 percent after three years.
Thalomid is only available through RevAid®, a controlled distribution program under which only program registered prescribers and pharmacists may prescribe and dispense Thalomid to patients who are registered and agree to the requirements of the RevAid® program.
We previously wrote that Celgene Inc. and Health Canada issued a safety warning about the risk of blood clots with Thalomid.
While uncommon, blood clots in the arteries can occur in patients taking Thalomid, especially during the first five months of use. Some clots resulted in death due to heart attack or stroke. A blood clot in the heart can cause chest pain, which can spread to the arms, neck, jaw, back, or stomach; the patient may also feel sweaty, out of breath, and nauseated. A blood clot in the brain can cause difficulty in seeing or speaking, which may be signs of a stroke. Patients who experience these symptoms should seek medical help immediately.
Health Canada authorized the use of Thalomid in very limited circumstances to treat multiple myeloma in patients 65 years of age and older. Thalidomide is approved for this use in the United States by the U.S. Food and Drug Administration (FDA), as well as to treat new lesions of leprosy. Both health agencies warn that Thalomid should never be taken by women who are pregnant or who could become pregnant while taking the drug. Even a single dose taken by a woman during pregnancy can cause severe birth defects or death to an unborn baby. Thalidomid was responsible for severe limb deformities and other birth defects in the early 1960s, when it was on the market as a sedative.