Summary of the safety profile
The most common adverse reactions are: diarrhoea (85%), rash (65%), ovarian toxicity in women of childbearing potential (60%), nausea (59%), fatigue (50%), hypophosphataemia (50%), headache (40%), and stomatitis (40%).
The most frequently reported serious adverse reaction was ovarian toxicity (premature menopause, 3%). The most common severe adverse reactions were diarrhoea (16%) and hypophosphataemia (13%).
Permanent discontinuation of nirogacestat due to an adverse event occurred in 19% of patients. The most common adverse reactions leading to discontinuation were diarrhoea (5%), ovarian toxicity (5%), and increased ALT (3%).
The frequency of dose interruption of nirogacestat due to adverse reactions was 59%. The most common adverse reactions leading to dose interruption were diarrhoea (11%), rash maculo-papular (10%), hypophosphatemia (6%) and nausea (5%).
The frequency of dose reduction of nirogacestat due to adverse reactions was 44%. The most common adverse reactions leading to dose reduction were diarrhoea (9%), rash maculo-papular (6%), stomatitis (3%), and hypophosphatemia (3%).
Tabulated list of adverse reactions
Unless otherwise stated, the frequencies of adverse reactions are based on all-cause adverse event frequencies identified in 88 patients exposed to nirogacestat 150 mg twice daily during a median duration of 21.5 months in clinical studies.
The adverse reactions are ranked under heading of frequency using the following convention: very common (≥ 1/10), common (≥ 1/100 to < 1/10), uncommon (≥ 1/1 000 to < 1/100), rare (≥ 1/10 000 to < 1/1 000), very rare (< 1/10 000) and not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
Table 2: Adverse reactions reported
| System organ class | Adverse reaction | All grades | Grades 3-4 |
| Gastrointestinal disorders | Diarrhoea | Very common | Very common |
| Nausea | Very common | Common |
| Stomatitisa | Very common | Common |
| Dry mouth | Very common | -- |
| Skin and subcutaneous disorders | Rashb | Very common | Common |
| Alopecia | Very common | -- |
| Folliculitis | Very common | Common |
| Hidradenitis | Common | Common |
| Dry skin | Very common | -- |
| Pruritis | Very common | -- |
| Neoplasms benign, malignant and unspecified | Basal cell carcinoma | Common | -- |
| Squamous cellc carcinoma | Common | -- |
| Metabolism and nutrition disorders | Hypophosphataemia | Very common | Very common |
| Hypokalaemia | Very common | Common |
| Nervous system disorders | Headache | Very common | -- |
| Dizziness | Very common | -- |
| Investigation | Proteinuria | Very common | -- |
| Glycosuria | Very common | -- |
| Blood and lymphatic system disorders | Eosinophilia | Very common | -- |
| Renal and urinary disorders | Renal tubular disorder | Common | -- |
| Injury, poisoning and procedural complications | Bone fractured | Common | -- |
| Hepatobiliary disorders | ALT increased | Very common | Common |
| AST increased | Very common | Common |
| Reproductive system and breast disorders | Ovarian toxicitye | Very common | -- |
| Respiratory, thoracic and mediastinal disorders | Cough | Very common | -- |
| Upper respiratory tract infectionf | Very common | -- |
| Dyspnoea | Very common | -- |
| Epistaxis | Very common | -- |
| General disorders and administration site conditions | Fatigue | Very common | Common |
| Influenza-like illness | Very common | -- |
a Stomatitis includes stomatitis, mouth ulceration, oral pain, and oropharyngeal pain.
b Rash includes rash maculo-papular, dermatitis acneiform, rash, rash erythematous, rash pruritic, and rash papular.
c Squamous cell carcinoma included squamous cell carcinoma of skin and squamous cell carcinoma.
d Bone fracture includes fracture, foot fracture, hand fracture, radius fracture, hip fracture and rib fracture.
e Ovarian toxicity includes ovarian failure, premature menopause, amenorrhoea, oligomenorrhoea, menstruation irregular, dysmenorrhoea, heavy menstrual bleeding, vulvovaginal dryness, hot flush, decreased anti-Müllerian hormone (AMH) and increased follicle-stimulating hormone (FSH).
f Upper respiratory tract infection (URTI) includes URTI, viral URTI, acute sinusitis, and sinusitis.
-- Represents no cases were reported.
Description of selected adverse reactions
The data described below reflect results of the randomised, double-blind, Phase 3 DeFi study in patients with desmoid tumours treated with 150 mg BID nirogacestat (N=69) or placebo (N=72) twice daily.
Diarrhoea
In the double-blind phase of the DeFi study, diarrhoea was reported in 84% of patients receiving nirogacestat compared to 35% in patients receiving placebo. Grade 3 events occurred in 16% and 1% of patients, respectively (see section 4.4). Grade ≤ 2 diarrhoea resolved in 74% of patients who continued on nirogacestat treatment. The median time to first onset of diarrhoea in patients receiving nirogacestat was 9 days (range 2 to 234 days). Diarrhoea led to dose reduction in 10% of patients and treatment discontinuation in 7% receiving nirogacestat.
Skin and subcutaneous tissue disorders
In the double‑blind phase of the DeFi study, dermatologic reactions were reported at a higher incidence in patients receiving nirogacestat than in those receiving placebo; they included maculo‑papular rash (32% vs 6%), hidradenitis (9% vs 0), and folliculitis (13% vs 0) (see section 4.4). The median time to rash events was 22 days (range 2 to 603 days). Skin and subcutaneous disorders led to dose reduction in 9% of patients receiving nirogacestat, including maculo‑papular rash in 4% and hidradenitis in 3%. Maculo‑papular rash led to treatment discontinuation in 1%.
Ovarian toxicity
In the double‑blind phase of the DeFi study, 75% of women of childbearing potential receiving nirogacestat reported ovarian toxicity (defined as ovarian failure, premature menopause, amenorrhea, oligomenorrhea, and menopause) compared to no patients receiving placebo. There were three serious adverse reactions of ovarian toxicity, all premature menopause, representing 11% of all participants reporting ovarian toxicity. The median time to first onset of ovarian toxicity was 8.9 weeks (range 1 day to 54 weeks), and the overall median duration was 18.9 weeks (range 11 days to 215 weeks). Ovarian toxicity has been reported to resolve in 79% of women of childbearing potential during treatment. Follow up information is available for all but two out of 27 patients; after stopping treatment, ovarian toxicity was reported to resolve in all women of childbearing potential for whom data are available. The median time to resolution after discontinuing nirogacestat was 10.9 weeks (range 4 to 18 weeks). Effects of nirogacestat on fertility are unknown (see section 4.4). An exposure-response relationship was identified between nirogacestat and serum follicular stimulating hormone (FSH) levels, with FSH increasing linearly with increasing serum concentrations of nirogacestat.
Electrolyte abnormalities
Electrolyte abnormalities were reported in patients receiving nirogacestat in the double‑blind phase of the DeFi study, including hypophosphataemia (43%) and hypokalaemia (12%), compared to 7% and 1%, respectively, in patients receiving placebo. Median time to first onset of hypophosphataemia and hypokalaemia was 15 days (range 1 to 833 days) and 15 days (range 1 to 57 days), respectively. Grade 3 events of hypophosphataemia and hypokalaemia occurred in 3% of patients receiving nirogacestat compared to no patients receiving placebo (see section 4.4). Hypophosphataemia and hypokalaemia led to dose reduction in 4% and 1% of patients receiving nirogacestat, respectively. Hypophosphataemia led to dose discontinuation in 1% of patients receiving nirogacestat.
Hepatic abnormalities
ALT and AST elevations were reported in 19% and 17%, respectively, of patients receiving nirogacestat in the double‑blind phase of the DeFi study compared to 8% and 11%, respectively, in patients receiving placebo. Median time to first onset of ALT and AST elevations was 22 days (ALT range 8 to 924 days; AST range 1 to 1023 days). Grade 3 ALT and AST elevations (> 5 x ULN) occurred in 3% of patients treated with nirogacestat compared to 1% in the placebo arm (see section 4.4). ALT and AST elevations each led to dose reduction in 1% of patients receiving nirogacestat. ALT and AST elevations led to dose discontinuation in 4% and 3% of patients receiving nirogacestat, respectively.
Non-melanoma skin cancers
Non-melanoma skin cancers were reported at a higher incidence in patients receiving nirogacestat than in those receiving placebo in the double‑blind phase of the DeFi study, including squamous cell carcinoma (3% vs 0) and basal cell carcinoma (1% vs 0), with one patient reporting both types of non‑melanoma skin cancer (see section 4.4). An additional two cases of non‑melanoma skin cancer were reported outside of the double‑blind phase of the DeFi study.
Proximal renal tubule effect
Glycosuria and proteinuria were observed in 52% and 46%, respectively, of patients receiving nirogacestat in the double‑blind phase of the DeFi study, compared with 1% and 39%, respectively, in patients receiving placebo. Median time to onset of glycosuria and proteinuria was 85 days (range 55 to 600 days) and 72 days (range 38 to 937 days), respectively. One patient in the DeFi study reported renal tubular disorder with increased urinary excretion of uric acid, glucose and phosphate, but no excess excretion of low molecular weight proteins (beta2‑microglobulin) or any change in renal function. The event was managed with dose reduction.
Bone fracture
In the double‑blind phase of the DeFi study, bone fractures were reported in 6% of patients receiving nirogacestat compared with no patients receiving placebo. All reports of bone fracture were non‑serious and Grade 1 or 2. The median time to first onset of bone fracture events in patients receiving nirogacestat was 125 days (range 1 to 739 days). Bone fracture events did not lead to dose reduction or treatment discontinuation in any patient receiving nirogacestat.
Paediatric population
Epiphyseal disorder, manifesting as a widening of the epiphyseal growth plate, was reported in 4 of 26 (15%) paediatric patients with open growth plates treated with nirogacestat outside of the DeFi study. The events included epiphysiolysis, hip fracture, epiphyseal disorder, and osteonecrosis. All 4 paediatric patients were between the ages of 11 and 12 years. See section 4.2 for information on paediatric use.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorization of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search MHRA Yellow Card in the Google Play or Apple App Store.