The New Drug Review for April
Accelerated approval has been granted to rucaparib (Rubraca) as monotherapy for patients with deleterious BRCA mutation-associated advanced ovarian cancer who have been treated with two or more chemotherapies.
Rucaparib is a poly (ADP-ribose) polymerase (PARP) enzyme inhibitor. By inhibiting PARP, rucaparib may cause increased formation of PARP-DNA complexes, resulting in DNA damage, apoptosis, and cell death. Candidates must have the BRCA mutation identified with The FoundationFocus CDxBRCA companion diagnostic test.
The National Cancer Institute estimates that 39% of women who inherit a harmful BRCA1 mutation and 11% to 17% of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by age 70. Before approval of rucaparib, few effective therapies existed for advanced mutant BRCA ovarian cancer after the failure of platinum-based therapy.
Approval of rucaparib was based on two multicenter single-arm open- label clinical trials that evaluated its efficacy (600 mg orally, bid) in 106 patients with advanced ovarian cancer that had progressed after two or more chemotherapies. In the approval studies, objective response rate (ORR) and duration of response (DOR) were assessed according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. With rucaparib, the investigator-assessed ORR was 54% (95% CI, 44-64). Complete response was confirmed in 10 patients (9%); partial response was seen in 48 (45%). Median duration of investigator-assessed confirmed response was 9.2 months (95% CI, 6.6-11.6 months).
The most common adverse reactions (≥ 20%; Grade 1-4) were nausea (77%), asthenia/fatigue (77%), vomiting (46%), anemia (44%), constipation (40%), dysgeusia (39%), decreased appetite (39%), diarrhea (34%), abdominal pain (32%), dyspnea (21%), and thrombocytopenia (21%).
No contraindications to rucaparib exist. Rucaparib has potential for serious risks, including myelodysplastic syndrome and acute myeloid leukemia. Rucaparib can cause fetal harm. Females should be advised to use effective contraception during treatment and for 6 months after receiving their last dose of rucaparib.
CBC should be monitored at baseline and monthly thereafter in all patients. Rucaparib should not be started until patients have recovered from any hematological toxicity caused by previous chemotherapy. Treatment should be interrupted and blood counts monitored weekly if any hematological toxicities occur.
Dosing and cost
The recommended dose of rucaparib is 600 mg (two 300-mg tablets) taken orally bid with or without food. Treatment should be continued until disease progression or unacceptable toxicity. If a dose is missed, instruct the patient to take the next dose at its scheduled time. Vomited doses should not be replaced.
Rucaparib is supplied as 300-mg and 200-mg tablets (200-mg tablets are to be used during dose reductions).
Average wholesale price for one month of rucaparib treatment ranges from $6,800 to $8,200. Patient assistance programs may be available to those who qualify.