New Enhertu Indications
Under its Priority Review program and with a Breakthrough Therapy designation, the FDA approved a new indication for Enhertu® (fam-trastuzumab-deruxtecan-nxki – Daiichi Sankyo) injection on Aug. 5, 2022, as the first targeted drug specifically to treat a newly differentiated variation of breast cancer. It now is indicated for patients who have cancer that expresses low amounts of human epidermal growth factor receptor 2 (HER2), that has spread despite prior treatment and that cannot be removed by surgery. Previously, HER2-low breast cancers were treated in the same way as HER2-negative (HER2-) breast cancers — with chemotherapy (chemo) and endocrine therapy. The National Cancer Institute estimates a potential patient population of just under 150,000 new cases of HER2-low breast cancer annually. Enhertu is a conjugate linking an antibody that sticks to HER2 proteins with a topoisomerase inhibitor that kills cancer cells. In the clinical trial for HER2-low breast cancer, progression-free survival (PFS) averaged 9.9 months for patients using Enhertu as compared with 5.1 months for those treated with chemo. Recommended dosing for treating breast cancer, 5.4mg/kg, is administered once every three weeks as an intravenous (IV) infusion.
On Aug. 11, 2022, Enhertu received a new Accelerated Approval as treatment for adults who have had at least one previous drug therapy for non-small cell lung cancer (NSCLC) that has spread or that is inoperable. The cancer also must test positive for activating HER2 mutations through an approved diagnostic test before treatment starts. NSCLC accounts for about 85% to 90% of the 237,000 cases of lung cancer diagnosed in the U.S. each year. Activating HER2 mutations are believed to affect as many as 4% of patients who have NSCLC – especially younger patients, women and never-smokers. In the phase II DESTINY-Lung02 clinical, the overall response rate (ORR) for patients infused IV with 5.4mg/kg of Enhertu once every three weeks was 57.7%. The average response lasted 8.7 months. Because the results are preliminary, full approval will need additional confirmation of benefits.
Enhertu originally was awarded Accelerated FDA Approval in December 2019 as third-line or later therapy for treating adults who have inoperable and/or metastatic HER2-positive (HER2+) breast cancer. Full approval for the initial indication was granted in May 2022, along with an extension to include advanced HER2+ breast cancer, which has returned within six months of anti-HER2-based treatment either in the metastatic setting or before (neoadjuvant) or after (adjuvant) primary treatment, which usually is surgery. On Jan. 15, 2021, it was approved for adults who have advanced HER2+ gastric or gastroesophageal junction (GEJ) adenocarcinoma that previously was treated with trastuzumab. A boxed warning and a Medication Guide for patients caution that using it may cause lung conditions, including interstitial lung disease, which could be fatal. It also may damage a developing baby, so women of childbearing age should use effective forms of contraception while being treated with Enhertu. Updated prescribing information can be found here.
Tabrecta Earns Full Approval
The FDA upgraded an Accelerated Approval from May 2020, to full approval for Tabrecta™ (capmatinib – Novartis) tablets on Aug. 10, 2022. A kinase inhibitor, it is indicated to treat adult patients who have metastatic or inoperable NSCLC that has METex14 — a specific mutation (exon 14 skipping) in the mesenchymal-epithelial transition (MET) gene. Around 3% to 5% of metastatic NSCLC cases have mutations that cause METex14. After a diagnostic test verifies the mutation, patients take 400mg of Tabrecta twice a day. Because it may damage the liver, patients taking Tabrecta should have liver function tests before and during treatment. It also may inflame or scar the lungs, harm developing babies and increase sensitivity to sunlight. Check here for revised prescribing information.
Broader Indication for Nubeqa
The indication for Nubeqa® (darolutamide – Bayer Healthcare) tablets was expanded to include a new combination therapy and a wider indication on Aug. 5, 2022. An androgen-receptor inhibitor, it was first FDA approved in 2019. Its initial approval is to be used either after an orchiectomy (surgical removal of the testes) or along with a gonadotropin-releasing hormone (GnRH) analog, such as Lupron Depot® (leuprolide) suspension or Zoladex® (goserelin) implant for treating patients who have non-metastatic castration-resistant prostate cancer. Nubeqa now also is indicated — along with docetaxel — for patients who have metastatic hormone-sensitive prostate cancer and who have had an orchiectomy or who are using a GnRH analog. The recommended dose is 600mg (2 tablets) twice a day along with a meal or snack. Docetaxel is given at 75mg/m2 as a 60-minute IV infusion once every three weeks. It must be administered in a healthcare setting that is staffed and equipped to handle any serious reactions that may occur. Here is revised prescribing information for Nubeqa.
Myfembree Given New Indication
On Aug. 5, 2022, Myfembree® (relugolix 40mg/estradiol 1mg/norethindrone acetate 0.5mg – Myovant Sciences/Pfizer) tablets was FDA approved to manage moderate-to-severe pain that is associated with endometriosis. Believed to affect about 6.5 million American women, endometriosis results when the tissues that line the uterus are displaced to other parts of the body – most commonly in the abdomen. The tissue deposits can swell and bleed in the same way that uterine linings do during normal menstrual cycles. One frequent symptom is pain. The dose of Myfembree is one tablet taken once daily. In addition to the hormones, estradiol and norethindrone, Myfembree contains relugolix, a GnRH receptor antagonist, which blocks the release of natural ovarian hormones. The estrogen it contains helps to decrease bone resorption and its norethindrone counters some of the drug’s uterine side effects. The original FDA approval for Myfembree, from May 2021, is to decrease heavy menstrual bleeding for premenopausal women who have uterine leiomyomas (fibroids). Non-cancerous growths in the uterus, fibroids affect an estimated 5 million women in the United States. Like all products that contain an estrogen and a progestin, Myfembree has a boxed warning that taking it may raise the chances of blood clots. It should not be prescribed for women who smoke, who have high blood pressure, who are over 35 years of age or who have a history of blood clots. Before beginning to take it, patients should be tested to rule out pregnancy and they should stop taking oral contraceptives that contain hormones. Current prescribing information is here.
Xofluza Gets Approval for Pediatric Patients
Xofluza ® (baloxavir marboxil), Genentech’s influenza (flu) treatment, gained FDA approval on Aug. 11, 2022, for children as young as five years old. Taken as one dose, it treats patients who have had acute, uncomplicated influenza for less than 48 hours. Xofluza also can be used to prevent flu after exposure. Doses are based on the patient’s weight. Those weighing less than 20kg (44 pounds) take 2mg/kg; those weighing between 20kg and 80kg (176 pounds) take 40mg; and those weighing more take 80mg. The only currently approved drug in a new class of antiviral agents called CAP endonuclease inhibitors, it blocks the activity of a protein that flu viruses need to divide. Because it attacks flu in a different way, Xofluza could be used in combination with a neuraminidase inhibitor, such as oseltamivir. Xofluza is marketed as individually blister-packed 40mg and 80mg tablets and as oral suspension containing 40mg/20mL. Here is prescribing information.
Tablet Form Approved for Calquence
Calquence® (acalabrutinib) tablets were FDA approved on Aug. 3, 2022. The drug inhibits Bruton tyrosine kinase (BTK), an enzyme that promotes the production, movement and binding of B-cells. In capsule form, it was given the FDA’s Accelerated Approval in October 2017 to treat adults who have mantle cell lymphoma (MCL) and who already have received one or more previous therapies. Clinical studies are ongoing to provide support for that indication, which is not yet verified for full approval. In 2019, full FDA approval was granted to the capsules for treating adults who have chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). However, blood levels of Calquence capsules may be reduced if they are taken at the same time that proton pump inhibitors (PPIs), H2 receptor blockers and/or antacids are used to decrease amounts of stomach acid. The tablet form has no restrictions on use with acid blockers. For the new formulation, recommended dosing for all three indications is one tablet (100mg) taken orally about once every 12 hours. Although they both are available in 100mg strengths, Calquence tablets and capsules cannot be exchanged for each other. Look here for Calquence tablet’s complete prescribing information.