New drug treats cancer based on biomarker, not location

This column reviews details on recent recalls, warnings, and approvals.


Recalls, warnings, safety updates

A warning about the risk of inaccurate results from certain lead tests that process venous blood samples. The LeadCare, LeadCare II, LeadCare Plus, and LeadCare Ultra testing systems are affected by this warning. The tests may provide inaccurate results for some children and adults, potentially leading to improper management and treatment of patients for lead exposure or poisoning. Discontinue use of these testing systems with venous blood samples, although they may still be used with capillary blood samples. The FDA and CDC are working with the manufacturer to investigate the root cause.

An expanded recall of amitriptyline tablets (50 mg) and phenobarbital tablets (15 mg, 30 mg, 60 mg, and 100 mg) due to a potential labeling mix-up. Manufacturer C.O. Truxton, Inc., first recalled one lot of 15-mg phenobarbital tablets because a bottle was found to contain 30-mg tablets. The recall was expanded to include all products that were repackaged into a Truxton Incorporated label and distributed nationwide to physician and veterinarian treatment centers.

Photo by ThinkStock
Photo by ThinkStock

A drug safety communication that canagliflozin (Invokana, Invokamet) causes an increased risk of leg and foot amputations. The conclusion is based on new data from two large clinical trials of the type 2 diabetes medication in which leg and foot amputations occurred about twice as often in patients treated with the drug versus placebo. Amputations of the toe and middle of the foot were most common, although leg amputations below and above the knee also occurred. The FDA is requiring the addition of new warnings about this risk, including a boxed warning, to canagliflozin drug labels.

A drug safety communication clarifying the risks of oral and injectable fluoroquinolones. Patient cases and research findings do not currently support reports that the antibiotics may result in detachment of the retina in the eyes, aortic aneurysm, or aortic dissection. The FDA will continue to assess safety issues with the drug class.

A drug safety communication about gadolinium-based contrast agents for MRI. An FDA review, initiated in July 2015, has identified no harmful health effects from gadolinium retained in the brain after use of these agents for MRI but will continue to assess safety through additional research.

Approvals

Pembrolizumab (Keytruda) to treat patients whose cancers have a specific biomarker. This is the first approval of a cancer treatment based on a common biomarker rather than where the tumor originated in the body. The drug targets the PD-1/PD-L1 pathway and is approved for patients with unresectable or metastatic solid tumors with a biomarker referred to as microsatellite instability-high or mismatch repair-deficient. The indication includes patients with solid tumors that have progressed despite prior treatment and patients with colorectal cancer that has progressed following treatment with certain chemotherapy drugs. The drug was studied in five uncontrolled, single-arm clinical trials including 149 patients who received the drug. In the trials, the most common cancers were colorectal, endometrial, and other gastrointestinal cancers. A total of 39.6% of the participants had a complete or partial response to the drug, and 78% of them had a response that lasted six months or more. Common side effects include fatigue, pruritus, diarrhea, decreased appetite, rash, pyrexia, cough, dyspnea, musculoskeletal pain, constipation, and nausea. Serious risks include immune-mediated side effects, such as pneumonitis, colitis, hepatitis, endocrinopathies, and nephritis.

Edaravone (Radicava), an intravenous infusion to treat patients with amyotrophic lateral sclerosis (ALS). Efficacy was demonstrated in a six-month placebo-controlled clinical trial of 137 participants in Japan. After 24 weeks, those receiving the orphan drug had less functional decline versus placebo. The most common adverse reactions were contusion and gait disturbance. Serious risks include hives, swelling, shortness of breath, and allergic reactions to sodium bisulfite.

Midostaurin (Rydapt) in combination with chemotherapy to treat adults with newly diagnosed acute myeloid leukemia who have FLT3, a specific genetic mutation. The kinase inhibitor is approved for use with a companion diagnostic to detect the mutation. Safety and efficacy were studied in a trial of 717 patients who had not been treated for acute myeloid leukemia. Patients who received combination therapy lived longer and went longer without certain complications (median 8.2 months vs. median 3 months) than those who received chemotherapy alone. Common side effects include febrile neutropenia, nausea, mucositis, vomiting, headache, petechiae, musculoskeletal pain, nosebleeds, device-related infection, hyperglycemia, and upper respiratory tract infection. The drug is also approved to treat aggressive systemic mastocytosis, systemic mastocytosis with associated hematological neoplasm, or mast-cell leukemia. Common side effects in these patients include nausea, vomiting, diarrhea, edema, musculoskeletal pain, abdominal pain, fatigue, upper respiratory tract infection, constipation, fever, headache, and shortness of breath.

First-time generic approvals

Azelastine hydrochloride/fluticasone propionate nasal spray (137 µg/50 µg) to treat allergic rhinitis. (Brand name: Dymista)

Dexlansoprazole delayed-release capsules (60 mg) to heal all grades of erosive esophagitis, maintain healed erosive esophagitis, relieve heartburn, and treat symptomatic nonerosive gastroesophageal reflux disease. (Brand name: Dexilant)

Diclofenac sodium topical solution (2% w/w) to treat the pain of osteoarthritis of the knee. (Brand name: Pennsaid)

Ezetimibe/atorvastatin tablets (10 mg/10 mg, 10 mg/20 mg, 10 mg/40 mg, 10 mg/80 mg) to manage lipid levels; to increase HDL cholesterol levels in patients with primary hyperlipidemia or mixed hyperlipidemia, and to manage cholesterol levels in patients with homozygous familial hypercholesterolemia as an adjunct to other lipid-lowering treatments. (Brand name: Liptruzet)

Ezetimibe/simvastatin tablets (10 mg/10 mg, 10 mg/20 mg, 10 mg/40 mg, 10 mg/80 mg) to manage lipid levels as adjunctive therapy to diet, to increase HDL cholesterol levels in patients with primary hyperlipidemia or mixed hyperlipidemia, and to manage cholesterol levels in patients with homozygous familial hypercholesterolemia as an adjunct to other lipid-lowering treatments. (Brand name: Vytorin)

Note: The FDA states that drugs are not always commercially available immediately after approval.