ERLEADA® (apalutamide) Continued to Demonstrate Significant Improvement in Overall Survival for Patients With Metastatic Castration-Sensitive Prostate Cancer: Final Analysis of the TITAN Study

Article

About one in eight American men will receive a prostate cancer diagnosis at some point in their lives; almost 250,000 of them were diagnosed last year, and more than 34,000 died.1 Approximately 40,000 annual prostate cancer diagnoses are, specifically, metastatic castration-sensitive prostate cancer (mCSPC).2 This subset of prostate cancer patients is broad and heterogenous, with a wide range of disease risk and volume.3

Androgen deprivation therapy (ADT), either through medical or surgical castration, is established as the initial treatment for prostate cancer. In the past five years, Phase 3 clinical trials have shown increased survival among patients receiving a combination of ADT and an androgen receptor inhibitor.4 In 2018, ERLEADA® (apalutamide) became the first androgen receptor blocker to be approved specifically for use in patients with non-metastatic castration-resistant prostate cancer (nmCRPC).5 At that time, its effectiveness in treating mCSPC was still being studied, but final analysis data are now available.

The TITAN trial was a phase 3, randomized, double-blind, placebo-controlled, multicenter study that evaluated ERLEADA® plus ADT in 1,052 patients with mCSPC.6 Primary results of this study, which were first presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting and published simultaneously in The New England Journal of Medicine,4 showed that both primary endpoints had been met, with a 33% decrease in risk of death (hazard ratio [HR]=0.67; 95% confidence interval [CI], 0.51-0.89; P=0.0053) and a 52% reduced risk of radiographic progression (HR=0.48; 95% CI, 0.39-0.60; P<0.0001) for patients in the ERLEADA® plus ADT group vs. placebo plus ADT group after 22.7 months of median follow-up.4 The secondary endpoint of median time to cytotoxic chemotherapy in patients treated with ERLEADA® plus ADT was also met, with a 61% risk reduction compared with placebo plus ADT (HR=0.39; 95% CI, 0.27-0.56; P<0.0001).4 Based on these results, the FDA approved ERLEADA® for the treatment of patients with mCSPC in 2019.5

After 44 months of median follow-up, the final analysis of the TITAN study has now further solidified the results of the primary analysis.6 Data presented at the American Society of Clinical Oncology’s Genitourinary (ASCO GU) Cancers Symposium and published in the Journal of Clinical Oncology showed a 35% reduction in risk of death with ERLEADA® plus ADT over placebo plus ADT.6 The median overall survival (OS) in the ERLEADA® arm was not reached; median OS in the placebo group was 52.2 months (HR=0.65; 95% CI, 0.53-0.79; P<0.0001).6 The median treatment duration for the group receiving ERLEADA® plus ADT was 39.3 months, compared with 20.2 months for the placebo plus ADT group.6 After the primary analysis data was unblinded in 2019, 39.5% of patients (n=208) in the placebo plus ADT group crossed over to the ERLEADA® plus ADT group.6 A sensitivity analysis adjusting for the crossover group showed further reduction of the risk of death from 35% to 48% (HR=0.52; 95% CI, 0.42-0.64; P<0.0001).6 These data are not included in the ERLEADA® prescribing information.

Additional endpoints in the TITAN final analysis that favored ERLEADA® plus ADT over placebo plus ADT included second progression-free survival (HR=0.62; 95% CI, 0.51-0.75) and time to castration resistance (HR=0.34; 95% CI, 0.29-0.41); in both cases, the median was not reached in the ERLEADA® plus ADT group. The median times to second progression and castration resistance for the placebo plus ADT group were 44 months and 11.4 months, respectively.6 Health-related quality of life (HRQoL) data, as assessed by the total Functional Assessment of Cancer Therapy–Prostate (FACT-P) questionnaire, was maintained with ERLEADA® plus ADT, consistent with the primary analysis.6 These data are not included in the ERLEADA® prescribing information.

Grade 3/4 treatment-emergent adverse events of special interest for ERLEADA® plus ADT, as reported in the TITAN final analysis, were rash (2.9%), fracture (1.5%), fall (0.7%), ischemic heart disease (1.5%), ischemic cerebrovascular disorders (0.8%), and seizure (0.1%).6 Safety and tolerability of ERLEADA® were consistent with previously reported data from the TITAN primary analysis. The most common adverse reactions (≥10%) in ERLEADA®-treated patients (≥2% over placebo) from the randomized placebo-controlled clinical trials (SPARTAN and TITAN) were fatigue, arthralgia, rash, decreased appetite, fall, decreased weight, hypertension, hot flush, diarrhea, and fracture.5

The final analysis of TITAN showed that, after nearly four years of median follow-up, ERLEADA® plus ADT significantly improved overall survival in patients with mCSPC vs. placebo plus ADT.6

ERLEADA® IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS

Cerebrovascular and Ischemic Cardiovascular Events — In a randomized study (SPARTAN) of patients with nmCRPC, ischemic cardiovascular events occurred in 4% of patients treated with ERLEADA® and 3% of patients treated with placebo. In a randomized study (TITAN) in patients with mCSPC, ischemic cardiovascular events occurred in 4% of patients treated with ERLEADA® and 2% of patients treated with placebo. Across the SPARTAN and TITAN studies, 5 patients (0.5%) treated with ERLEADA®, and 2 patients (0.2%) treated with placebo died from an ischemic cardiovascular event. Patients with history of unstable angina, myocardial infarction, congestive heart failure, stroke, or transient ischemic attack within 6 months of randomization were excluded from the SPARTAN and TITAN studies.

In the SPARTAN study, cerebrovascular events occurred in 4.7% of patients treated with ERLEADA® and 0.8% of patients treated with placebo. In the TITAN study, cerebrovascular events occurred in 1.9% of patients treated with ERLEADA® and 2.1% of patients treated with placebo. Across the SPARTAN and TITAN studies, 3 patients (0.2%) treated with ERLEADA®, and 2 patients (0.2%) treated with placebo died from a cerebrovascular event.

Cerebrovascular and ischemic cardiovascular events, including events leading to death, occurred in patients receiving ERLEADA®. Monitor for signs and symptoms of ischemic heart disease and cerebrovascular disorders. Optimize management of cardiovascular risk factors, such as hypertension, diabetes, or dyslipidemia. Consider discontinuation of ERLEADA® for Grade 3 and 4 events.

Fractures— In a randomized study (SPARTAN) of patients with nmCRPC, fractures occurred in 12% of patients treated with ERLEADA® and in 7% of patients treated with placebo. In a randomized study (TITAN) of patients with mCSPC, fractures occurred in 9% of patients treated with ERLEADA® and in 6% of patients treated with placebo. Evaluate patients for fracture risk. Monitor and manage patients at risk for fractures according to established treatment guidelines and consider use of bone-targeted agents.

Falls — In a randomized study (SPARTAN), falls occurred in 16% of patients treated with ERLEADA® compared with 9% of patients treated with placebo. Falls were not associated with loss of consciousness or seizure. Falls occurred in patients receiving ERLEADA® with increased frequency in the elderly. Evaluate patients for fall risk.

Seizure — In 2 randomized studies (SPARTAN and TITAN), 5 patients (0.4%) treated with ERLEADA® and 1 patient treated with placebo (0.1%) experienced a seizure. Permanently discontinue ERLEADA® in patients who develop a seizure during treatment. It is unknown whether anti-epileptic medications will prevent seizures with ERLEADA®. Advise patients of the risk of developing a seizure while receiving ERLEADA® and of engaging in any activity where sudden loss of consciousness could cause harm to themselves or others.

Embryo-Fetal Toxicity — The safety and efficacy of ERLEADA® have not been established in females. Based on its mechanism of action, ERLEADA® can cause fetal harm and loss of pregnancy when administered to a pregnant female. Advise males with female partners of reproductive potential to use effective contraception during treatment and for 3 months after the last dose of ERLEADA® [see Use in Specific Populations (8.1, 8.3)].

ADVERSE REACTIONS

Adverse Reactions — The most common adverse reactions (≥10%) that occurred more frequently in the ERLEADA®-treated patients (≥2% over placebo) from the randomized placebo-controlled clinical trials (TITAN and SPARTAN) were fatigue, arthralgia, rash, decreased appetite, fall, weight decreased, hypertension, hot flush, diarrhea and fracture.

Laboratory Abnormalities — All Grades (Grade 3-4)

• Hematology — In the TITAN study: white blood cell decreased ERLEADA® 27% (0.4%), placebo 19% (0.6%). In the SPARTAN study: anemia ERLEADA® 70% (0.4%), placebo 64% (0.5%); leukopenia ERLEADA® 47% (0.3%), placebo 29% (0%); lymphopenia ERLEADA® 41% (2%), placebo 21% (2%)

• Chemistry — In the TITAN study: hypertriglyceridemia ERLEADA® 17% (3%), placebo 12% (2%). In the SPARTAN study: hypercholesterolemia ERLEADA® 76% (0.1%), placebo 46% (0%); hyperglycemia ERLEADA® 70% (2%), placebo 59% (1%); hypertriglyceridemia ERLEADA® 67% (2%), placebo 49% (0.8%); hyperkalemia ERLEADA® 32% (2%), placebo 22% (0.5%)

Rash — In 2 randomized studies, rash was most commonly described as macular or maculopapular. Adverse reactions of rash were 26% with ERLEADA® vs 8% with placebo. Grade 3 rashes (defined as covering >30% body surface area [BSA]) were reported with ERLEADA® treatment (6%) vs placebo (0.5%).

The onset of rash occurred at a median of 83 days. Rash resolved in 78% of patients within a median of 78 days from onset of rash. Rash was commonly managed with oral antihistamines, topical corticosteroids, and 19% of patients received systemic corticosteroids. Dose reduction or dose interruption occurred in 14% and 28% of patients, respectively. Of the patients who had dose interruption, 59% experienced recurrence of rash upon reintroduction of ERLEADA®.

Hypothyroidism — In 2 randomized studies, hypothyroidism was reported for 8% of patients treated with ERLEADA® and 2% of patients treated with placebo based on assessments of thyroid-stimulating hormone (TSH) every 4 months. Elevated TSH occurred in 25% of patients treated with ERLEADA® and 7% of patients treated with placebo. The median onset was at the first scheduled assessment. There were no Grade 3 or 4 adverse reactions. Thyroid replacement therapy, when clinically indicated, should be initiated or dose adjusted.

DRUG INTERACTIONS

Effect of Other Drugs on ERLEADA® — Co-administration of a strong CYP2C8 or CYP3A4 inhibitor is predicted to increase the steady-state exposure of the active moieties. No initial dose adjustment is necessary; however, reduce the ERLEADA® dose based on tolerability [see Dosage and Administration (2.2)].

Effect of ERLEADA® on Other Drugs

CYP3A4, CYP2C9, CYP2C19, and UGT Substrates — ERLEADA® is a strong inducer of CYP3A4 and CYP2C19, and a weak inducer of CYP2C9 in humans. Concomitant use of ERLEADA® with medications that are primarily metabolized by CYP3A4, CYP2C19, or CYP2C9 can result in lower exposure to these medications. Substitution for these medications is recommended when possible or evaluate for loss of activity if medication is continued. Concomitant administration of ERLEADA® with medications that are substrates of UDP-glucuronosyl transferase (UGT) can result in decreased exposure. Use caution if substrates of UGT must be co-administered with ERLEADA® and evaluate for loss of activity.

P-gp, BCRP or OATP1B1 Substrates — Apalutamide is a weak inducer of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and organic anion transporting polypeptide 1B1 (OATP1B1) clinically. Concomitant use of ERLEADA® with medications that are substrates of P-gp, BCRP, or OATP1B1 can result in lower exposure of these medications. Use caution if substrates of P-gp, BCRP or OATP1B1 must be co-administered with ERLEADA® and evaluate for loss of activity if medication is continued.

Please see the full Prescribing Information for ERLEADA®.
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References

  1. American Cancer Society. Key statistics for prostate cancer: Prostate cancer facts. Accessed May 2021.​ https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html
  2. Scher HI, Solo K, Valant J, Todd MB, et al. Prevalence of prostate cancer clinical states and mortality in the United States: estimates using a dynamic progression model. PLoS One. 2015;10(10):1-2.
  3. Francini E and Taplin ME. Prostate cancer: Developing novel approaches to castration-sensitive disease. Accessed May 2021. https://onlinelibrary.wiley.com/doi/pdf/10.1002/cncr.30329
  4. Chi KN, Agarwal N, Bjartell A, et al. Apalutamide for metastatic, castration-sensitive prostate cancer. N Engl J Med. 2019;381(1):13-24.
  5. ERLEADA. Prescribing information. Janssen; 2020.
  6. Chi KN, Chowdhury S, Bjartell A, et al. Apalutamide in patients with metastatic castration-sensitive prostate cancer: final survival analysis of the randomized, double-blind, phase III TITAN study. [published online ahead of print April 29, 2021]. J Clin Oncol. doi:10.1200/JCO.20.03488