Amivantamab-Vmjw: A Novel Treatment for Patients with NSCLC Harboring EGFR Exon 20 Insertion Mutation after Progression on Platinum-Based Chemotherapy

OBJECTIVE

This study is a comprehensive review of the clinical pharmacology, pharmacokinetics, efficacy, safety, and clinical applicability of amivantamab-vmjw for metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion (exon20ins) mutation.

DATA SYNTHESIS

The literature search to identify clinical trials returned only the CHRYSALIS phase 1 study. In a phase I trial, amivantamab-vmjw was associated with an overall response rate (ORR) of 40% (95% CI, 29-51) in the EGFR exon20ins NSCLC patient population (n = 81) after platinum-based chemotherapy. There were 3 complete responses (CRs) and 29 partial responses (PRs). The median duration of response (DOR) was 11.1 months (95% CI, 6.9-not reached; NR). The median progression-free survival (PFS) was 8.3 months (95% CI, 6.5-10.9), and overall survival (OS) was 22.8 months (95% CI, 14.6-NR).

APPLICATION TO CLINICAL PRACTICE

This review summarizes the pharmacology, clinical evidence, and use of amivantamab-vmjw for patients with locally advanced or metastatic NSCLC with EGFR exon20ins mutation.

CONCLUSION

The FDA approval of amivantamab-vmjw, the first bispecific antibody to target the exon20ins mutation, represents an important advancement in the treatment of patients with NSCLC with limited effective treatment options. The initial findings of the CHRYSALIS trial demonstrate an overall tumor response benefit with an acceptable safety profile.

Bone health effects of androgen-deprivation therapy and androgen receptor inhibitors in patients with nonmetastatic castration-resistant prostate cancer

Background

Osteoporosis is a skeletal disorder characterized by compromised bone strength, resulting in increased fracture risk. Patients with prostate cancer may have multiple risk factors contributing to bone fragility: advanced age, hypogonadism, and long-term use of androgen-deprivation therapy. Despite absence of metastatic disease, patients with nonmetastatic castrate-resistant prostate cancer receiving newer androgen receptor inhibitors can experience decreased bone mineral density. A systematic approach to bone health care has been hampered by a simplistic view that does not account for heterogeneity among prostate cancer patients or treatments they receive. This review aims to raise awareness in oncology and urology communities regarding the complexity of bone health, and to provide a framework for management strategies for patients with nonmetastatic castrate-resistant prostate cancer receiving androgen receptor inhibitor treatment.

Methods

We searched peer-reviewed literature on the PubMed database using key words “androgen-deprivation therapy,” “androgen receptor inhibitors,” “bone,” “bone complications,” and “nonmetastatic prostate cancer” from 2000 to present.

Results

We discuss how androgen inhibition affects bone health in patients with nonmetastatic castrate-resistant prostate cancer. We present data from phase 3 trials on the three approved androgen receptor inhibitors with regard to effects on bone. Finally, we present management strategies for maintenance of bone health.

Conclusions

In patients with nonmetastatic castrate-resistant prostate cancer, aging, and antiandrogen therapy contribute to bone fragility. Newer androgen receptor inhibitors were associated with falls or fractures in a small subset of patients. Management guidelines include regular assessment of bone density, nutritional guidance, and use of antiresorptive bone health agents when warranted.

Androgen receptor inhibitor treatments: Cardiovascular adverse events and comorbidity considerations in patients with non-metastatic prostate cancer

OBJECTIVES

Prostate cancer and cardiovascular (CV) disease share several risk factors, with the incidence of both rising with increasing age. Systemic prostate cancer therapies may increase CV risk. For example, gonadotropic releasing hormone agonists have been associated with increased development of CV risk factors, and potentially with CV disease. For men with non-metastatic castration-resistant prostate cancer (nmCRPC), the opportunity to mitigate CV risk by appropriate selection of therapy (i.e., use of newer agents such as androgen receptor inhibitors) may be possible. The phase 3 PROSPER, SPARTAN, and ARAMIS trials for enzalutamide, apalutamide, and darolutamide, the 3 approved androgen receptor inhibitors for men with nmCRPC, were all associated with increased metastasis-free survival in patients with metastatic castration-resistant prostate cancer (mCRPC). Our objective in writing this review is to improve awareness of the relationship between long-term androgen deprivation and increased risk for CV disease and inform treatment decision making for patients with mCRPC who also have CV comorbidities.

METHODS

The PubMed database was searched from 2010 to November 5, 2019 for articles pertaining to androgen receptor inhibitors, androgen inhibition, apalutamide, darolutamide, enzalutamide, CV, and CaP.

RESULTS

We found literature describing the relationship between androgen inhibition and CV disease and risks. Given the increased risk of CV disease due to exposure to gonadotropic releasing hormone agonist therapy alone, understanding the potential for additional CV risks is important for patients with CV comorbidities when an androgen receptor inhibitor is added to their treatment. Another important consideration is the possibility of drug-drug interactions with comedications.

CONCLUSION

Management strategies for patients with mCRPC also treated for comorbidities including CV disease require appropriate selection of therapy, diet, and exercise to meet the needs of the individual patient profile.

Response to PARP inhibitor therapy in metastatic castrate-resistant prostate cancer (mCRPC) patients with BRCA1/2 versus ATM mutations

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Background: Poly ADP-ribose polymerase inhibitors (PARPi) are being studied as a treatment option for men with mCRPC and deficient homologous recombination DNA repair. While the FDA has granted “breakthrough” designation status to olaparib for use in mCRPC patients with either BRCA1/2 or ATM mutations, it is not known if responsiveness to PARPi may be influenced by the mutation type. Because ATM functions as a sensor of DNA damage rather than a mediator of DNA repair, we hypothesized that patients with ATM mutations may not show robust responses to PARPi therapy compared to those with BRCA1/2 mutations. Methods: We conducted a retrospective analysis of mCRPC patients treated with off-label olaparib at Johns Hopkins Hospital and Mayo Clinic Scottsdale who had somatic or germline mutations in BRCA1/ 2 or ATM. The primary endpoint was PSA50 response. Secondary endpoints included overall survival (OS) and radiographic/clinical progression-free survival (PFS). Results: 40 men received olaparib for mCRPC of which 17 had pathogenic mutations (5 ATM-mutant, 12 BRCA1/2-mutant). Eleven (65%) had germline and 6 (35%) had somatic alterations. Five (29%) had Gleason sum ≤7 at diagnosis, 4 (24%) had Gleason sum 8, and 8 (47%) had Gleason sum ≥9. Three (18%) had metastatic disease at diagnosis. Mean age at start of olaparib therapy was 65.6 (range, 52-76) years. Prior chemotherapy was received by 59% of men, and prior abiraterone/enzalutamide by 88% of men. Eleven (65%) had extra-osseous metastases at start of therapy. PSA50 responses were achieved by 10/12 men (83%) with BRCA1/2 mutations and 0/5 men (0%) with ATM mutations (Fisher’s exact test, P= 0.003). Men with BRCA1/2 mutations had a median PFS of 12.3 mo versus 3.3 mo for those with ATM mutations (HR 0.14, 95%CI 0.03-0.60; P= 0.008). There was no difference in OS (HR 0.24, 95%CI 0.03-1.173; P= 0.16). Conclusions: Men with mCRPC harboring mutations in BRCA1/2 appear to have better PSA responses and longer PFS with olaparib compared to men with ATM mutations. ATM-mutant mCRPC patients may require alternative therapies ( e.g. chemotherapy, ATR inhibitors). Larger prospective studies are needed to confirm or refute these preliminary findings.

Impact of pharmacist-led monitoring of olaparib (O) for metastatic castrate resistant prostate cancer (mCRPC)

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Background: O is a PARP inhibitor that has received breakthrough designation for use in mCRPC based on a study in which a subset of 16 patients with DNA repair defects had an 80% response rate. O is an oral tablet taken twice daily. Studies have demonstrated that compliance with oral agents is often poor, and the less frequent contact with medical staff increases the risk of toxicities when compared to IV therapies. This is compounded by a bias where oral medications are thought of as less toxic than IV medications. The toxicities of O include myelosuppression, nausea, vomiting, and fatigue. Our practice employs a pharmacist to conduct weekly phone calls for toxicity management, monitor patient adherence, and monitor for drug-drug interactions. We report our experience with patient adherence, toxicities, and response with O in mCRPC. Methods: A single institution, retrospective review was performed on 14 mCRPC patients treated with O from November 2015 - October 2016. Adherence and toxicity data were assessed and documented via phone calls conducted by a clinical pharmacist. The primary outcomes were number of missed doses, incidence of toxicities, and dose modifications. The secondary outcome was response rate, defined as a 50% reduction in PSA or radiographic response according to RECIST 1.1 for a duration of greater than 3 months. Results: Patients reported taking 99% of the prescribed doses. The toxicities observed most commonly were fatigue (64%), nausea (57%) and anemia (57%). As a result of toxicities, four patients required a dose reduction to 300 mg BID, three patients required a dose reduction to 200 mg BID and two patients were initiated on 200 mg BID and maintained on that dose until progression. Partial responses were seen in 6 of 14 patients. Conclusions: Our pharmacist led adherence program facilitated timely dose adjustments and high patient adherence. Response rates were comparable to published data.