Combination Therapy Dramatically Extends Survival for Men with BRCA-Mutated Advanced Prostate Cancer
'Very Impressive' Survival With Combo in First-Line Prostate Cancer Study | MedPage Today
A Landmark Study Shows the One-Two Punch of Olaparib Plus Abiraterone More Than Doubles Survival Compared to Abiraterone Alone — But Only If You Know Your Genetic Status
BLUF (Bottom Line Up Front)
For men with metastatic castration-resistant prostate cancer (mCRPC) who carry BRCA1 or BRCA2 gene mutations, combining the PARP inhibitor olaparib (Lynparza) with the hormone therapy abiraterone (Zytiga) as first-line treatment produces a median overall survival of 68 months — nearly 5.7 years — compared to just 28 months with abiraterone alone. These results, presented at the ASCO Genitourinary Cancers Symposium in San Francisco on February 27, 2026, confirm that getting the combination upfront is superior to receiving each drug sequentially. The most important takeaway for patients: if you have not yet had genetic testing, ask your doctor about it now. Knowing whether you carry a BRCA1/2 or ATM mutation could meaningfully change your treatment plan and your survival odds.
What Is This All About?
Every prostate cancer patient deserves to know that our cancer does not come in one flavor. Beneath the surface, the biology varies enormously from man to man — and one of the most important variables is whether a tumor carries mutations in genes responsible for repairing DNA damage.
About 20–25% of men with mCRPC carry mutations in genes called homologous recombination repair (HRR) genes, and the most clinically important of these are BRCA1, BRCA2, and ATM. These mutations can be inherited (germline) or acquired by the tumor itself (somatic). Men with BRCA2 mutations in particular tend to have more aggressive disease — but they also appear to be the patients who benefit most from a relatively new class of drugs called PARP inhibitors.
Understanding why requires a brief look under the hood.
The Science: Two Attack Mechanisms Working Together
Cancer cells need to repair their own DNA to survive. BRCA-mutated tumors are already hobbled in one DNA repair pathway. A PARP inhibitor like olaparib blocks another repair pathway, creating what scientists call "synthetic lethality" — the cancer cell can no longer repair itself and dies. Think of it like cutting two load-bearing beams in a building at the same time.
Meanwhile, abiraterone attacks the tumor from a completely different angle by cutting off the testosterone supply that prostate cancer needs to grow. It works by blocking an enzyme called CYP17A1 that the body uses to make androgens (male hormones), even outside the testes. When you suppress androgens and inhibit DNA repair simultaneously, the two drugs appear to work synergistically — each one making the other more effective.
Laboratory research showed years ago that PARP1 (the enzyme olaparib blocks) actually interacts with androgen signaling, and that androgen-blocking drugs can themselves suppress the HRR repair pathway. In other words, the two drugs appear to prime each other's effectiveness — a virtuous cycle that delivers far more benefit than either alone.
The BRCAAway Trial: The Study That Answers a Key Question
The new data come from the BRCAAway trial (NCT03012321), a Phase 2 study designed in 2016 at Northwestern University's Robert H. Lurie Comprehensive Cancer Center by Dr. Maha Hussain and colleagues. This trial was specifically designed to answer a question that the larger Phase 3 studies could not fully address: Is it better to give both drugs together from the start, or to give one and then switch to the other when the first stops working?
Sixty-one patients with mCRPC who carried BRCA1/2 or ATM mutations were randomly assigned to one of three groups:
- Arm 1: Abiraterone plus prednisone alone (19 patients)
- Arm 2: Olaparib alone (21 patients)
- Arm 3: Olaparib plus abiraterone and prednisone combined (21 patients)
Patients in Arms 1 and 2 were allowed to "cross over" to the other drug when their disease progressed — simulating sequential therapy. This design is key because it lets us compare combination versus sequential approaches directly.
The Results: Stunning Survival Numbers
The updated overall survival data, presented at the 2026 ASCO GU Symposium, are striking:
| Treatment Arm | Median Overall Survival | 5-Year Survival Rate |
|---|---|---|
| Abiraterone + Prednisone alone | 28 months | 31% |
| Olaparib alone | 37 months | 42% |
| Olaparib + Abiraterone + Prednisone | 68 months | 55% |
The combination reduced the risk of death by 61% compared to abiraterone alone (Hazard Ratio 0.39), meaning that at any given point in time, men on the combination therapy were far less likely to have died.
Progression-free survival — the time before the cancer significantly worsened — was equally impressive. The combination produced a median of 39 months without progression, versus 8.6 months for abiraterone alone and 14 months for olaparib alone.
Critically, when patients in Arms 1 and 2 crossed over to the alternative drug at progression, the total survival from the time of starting the study (about 16 months each way) still fell far short of the 68 months achieved by starting with the combination upfront. Sequential therapy, even with crossover, simply cannot replicate what upfront combination therapy achieves.
Dr. Hussain summarized the findings this way: the combination "was well tolerated and resulted in better response rates, progression-free survival, overall survival, and also PSA responses, compared to olaparib or abiraterone, despite allowing crossover."
A fascinating sub-analysis of circulating tumor cells from BRCAAway found that men with BRCA2 mutations who have high androgen receptor (AR) expression — which ordinarily predicts poor response to either drug alone — still responded well to the combination. The researchers suggest the combination may "rescue" patients with this aggressive AR-driven biology. This could partly explain why starting both drugs together works so much better than sequential use.
Is This Trial Definitive?
BRCAAway is a Phase 2 study with only about 20 patients per arm — meaning results are promising but not yet proof at the gold-standard level. ASCO discussant Dr. Evan Y. Yu of the University of Washington noted that the results are "very impressive" but cautioned that the small size creates "potential for imbalances" between the groups. For instance, more patients in the abiraterone-alone arm had worse performance status at the start, which could partially account for their shorter survival.
Dr. Kim Chi of BC Cancer Vancouver, commenting on the earlier BRCAAway data, called it "a hypothesis-generating trial with a small number of patients, so we must be careful about overinterpreting the results. Nevertheless, it does support the use of upfront combined ARPI plus PARP inhibition in patients with HRR mutations, particularly BRCA2."
In short: BRCAAway is not the final word, but it is a compelling and important piece of evidence that reinforces and extends what larger trials have already shown.
How BRCAAway Fits With the Larger Picture
The BRCAAway results do not stand alone. They are part of a body of evidence from three major Phase 3 trials that have already changed the standard of care for BRCA-mutated mCRPC:
The PROpel Trial (NCT03732820) was a large, international, randomized, double-blind Phase 3 trial comparing olaparib plus abiraterone against placebo plus abiraterone in first-line mCRPC patients regardless of mutation status. In the BRCA-mutated subgroup specifically, the combination produced a remarkable reduction in the risk of death (Hazard Ratio 0.29). A post-hoc analysis from PROpel presented at ASCO GU 2025 confirmed significant rPFS and overall survival benefits in both germline and somatic BRCA-mutated patients. Based on PROpel, the FDA approved olaparib plus abiraterone for BRCA-mutated mCRPC on May 31, 2023.
The MAGNITUDE Trial (NCT03748641) studied niraparib (Akeega) plus abiraterone versus placebo plus abiraterone in biomarker-selected mCRPC patients. The FDA subsequently approved this combination for BRCA-mutated mCRPC as well.
The TALAPRO-2 Trial (NCT03395197) studied talazoparib (Talzenna) plus enzalutamide and led to FDA approval of that combination for the broader population of HRR gene-mutated mCRPC patients on June 20, 2023.
Together, these three Phase 3 trials and now BRCAAway's updated survival data make a powerful and consistent case: for men whose tumors carry BRCA1/2 mutations, hitting cancer simultaneously with a hormone-blocking drug and a PARP inhibitor from day one produces far better outcomes than using either alone.
What Does This Mean for Safety?
A natural concern is whether combining two potent cancer drugs means twice the side effects. The BRCAAway data are reassuring. The most common side effects of olaparib-containing regimens include anemia, fatigue, nausea, and gastrointestinal symptoms — generally manageable problems. Grade 3 (severe) treatment-related adverse events were similar across all three arms: four in the abiraterone arm, three in the olaparib arm, and four in the combination arm. No Grade 4 or Grade 5 (life-threatening or fatal) treatment-related events were observed in any arm. As Dr. Hussain noted, some patients were on treatment for years — a testament to tolerability.
One longer-term safety concern worth flagging for discussion with your doctor: an analysis published in the journal AME Clinical Trials Review in 2025 noted that PARP inhibitors are associated with a small but real risk of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), conditions affecting blood cell production. Rates in the major mCRPC trials have been very low, but this bears watching — especially as men remain on treatment for longer periods.
What About Men With ATM Mutations?
While most of the dramatic survival benefit in BRCAAway was seen in men with BRCA1/2 mutations, approximately 11 patients in the trial carried ATM mutations (a different HRR gene). The data for ATM patients are less definitive, and the trial was not large enough to draw clear conclusions for this subgroup. At present, clinical practice guidelines and FDA approvals focus primarily on BRCA1/2 mutations for this combination approach, though the combination of talazoparib plus enzalutamide has broader approval covering the wider HRR-mutated population. Men with ATM or other HRR mutations should have a detailed discussion with their oncologist about which treatment approach is most appropriate for them.
The Critical Role of Genetic Testing
All of this makes one message absolutely clear: every man with advanced prostate cancer should be offered genetic testing — both tumor (somatic) testing and germline (inherited) testing.
Germline testing is important not only for treatment decisions but also because BRCA mutations can be passed to children and have implications for other cancers (breast, ovarian, pancreatic) in family members. If you have not been tested, ask your oncologist about next-generation sequencing (NGS) of your tumor tissue or circulating tumor DNA, as well as germline blood testing.
If you've been told testing isn't available or isn't covered, know that several programs and pharmaceutical company assistance initiatives exist to help with access and cost. Your support group advocate can help you navigate these options.
Takeaways for Patients and Caregivers
For men newly diagnosed with first-line mCRPC who carry BRCA1/2 mutations: the evidence now strongly supports starting with olaparib plus abiraterone together rather than one at a time. The FDA approved this combination in 2023, so it is available today.
For men already on hormone therapy for mCRPC and not yet tested: ask about genetic testing now. If you carry a BRCA1/2 mutation and haven't yet received a PARP inhibitor, there may still be treatment options to discuss with your physician.
For men on abiraterone or enzalutamide alone who carry BRCA1/2 mutations: this data adds to the growing case that combination therapy from the start provides the best outcomes, though decisions should always be individualized based on your full medical picture.
For everyone: this field is moving fast. The combination of hormone therapies and PARP inhibitors is now being tested in even earlier stages of disease — including metastatic hormone-sensitive prostate cancer (mHSPC) — through trials like AMPLITUDE and TALAPRO-3. Results in those settings could further expand treatment options in the years ahead.
Verified Sources and Formal Citations
1. BRCAAway Trial — 2026 ASCO GU Updated Overall Survival Data (Primary Source for This Article) Hussain MH, Kocherginsky M, Paller CJ, et al. Overall survival from the phase 2 trial of abiraterone, olaparib, or abiraterone + olaparib in first-line metastatic castration-resistant prostate cancer (mCRPC) with DNA repair defects (BRCAAway). Presented at ASCO GU 2026; February 26–28, 2026; San Francisco, CA. Coverage: https://www.cancertherapyadvisor.com/reports/abiraterone-prednisone-olaparib-os-brca1-2-atm-altered-mcrpc/ Coverage: https://www.medpagetoday.com/meetingcoverage/asco-gu/113148
2. BRCAAway Trial — Published Phase 2 Results (PFS Primary Data) Hussain M, Kocherginsky M, Agarwal N, et al. Abiraterone, Olaparib, or Abiraterone + Olaparib in First-Line Metastatic Castration-Resistant Prostate Cancer with DNA Repair Defects (BRCAAway). Clin Cancer Res. 2024;30(19):4318–4328. https://doi.org/10.1158/1078-0432.CCR-24-1402 PubMed: https://pubmed.ncbi.nlm.nih.gov/39115414/
3. BRCAAway Circulating Tumor Cell Sub-Analysis Reichert ZR, Hussain MHA, Lovett JL, et al. Circulating tumor cell expression analysis from the phase 2 trial of abiraterone, olaparib, or abiraterone + olaparib in first-line mCRPC with DNA repair defects (BRCAAway). J Clin Oncol. 2025;43(suppl 5):199. https://ascopubs.org/doi/10.1200/JCO.2025.43.5_suppl.199
4. PROpel Trial — Final Overall Survival Results Saad F, Clarke NW, Oya M, et al. Olaparib plus abiraterone versus placebo plus abiraterone in metastatic castration-resistant prostate cancer (PROpel): final prespecified overall survival results of a randomised, double-blind, Phase 3 trial. Lancet Oncol. 2023;24(10):1094–1108. https://doi.org/10.1016/S1470-2045(23)00382-0
5. PROpel Trial — BRCA Subgroup Post-Hoc Analysis (ASCO GU 2025) Saad F, Armstrong A, Oya M, et al. Efficacy of olaparib plus abiraterone versus placebo plus abiraterone in patients with mCRPC with a germline or somatic BRCA mutation in the PROpel trial. J Clin Oncol. 2025;43(suppl 5):219. https://www.onclive.com/view/olaparib-plus-abiraterone-improves-radiographic-pfs-and-os-in-brca-mcrpc
6. FDA Approval — Olaparib Plus Abiraterone for BRCA-Mutated mCRPC (May 31, 2023) U.S. Food and Drug Administration. FDA approves olaparib with abiraterone and prednisone (or prednisolone) for BRCA-mutated metastatic castration-resistant prostate cancer. May 31, 2023. https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-olaparib-abiraterone-and-prednisone-or-prednisolone-brca-mutated-metastatic-castration
7. MAGNITUDE Trial Results Chi KN, Rathkopf D, Smith MR, et al. Niraparib and abiraterone acetate for metastatic castration-resistant prostate cancer. J Clin Oncol. 2023;41(18):3339–3351. Chi KN, Sandhu S, Smith MR, et al. Niraparib plus abiraterone acetate with prednisone in patients with mCRPC and homologous recombination repair gene alterations: second interim analysis of the randomized phase III MAGNITUDE trial. Ann Oncol. 2023;34(9):772–782. Final OS: Chi KN, et al. Eur Urol Oncol. 2025;8:986–998.
8. TALAPRO-2 Trial Results and FDA Approval Agarwal N, Azad AA, Carles J, et al. Talazoparib plus enzalutamide in men with first-line metastatic castration-resistant prostate cancer (TALAPRO-2): a randomised, placebo-controlled, phase 3 trial. Lancet. 2023;402(10398):291–303. Fizazi K, Azad AA, Matsubara N, et al. First-line talazoparib with enzalutamide in HRR-deficient mCRPC: the phase 3 TALAPRO-2 trial. Nat Med. 2024;30(1):257–264. FDA Approval Summary: Dhawan M, et al. JCO. Published 2024. PMC: https://pmc.ncbi.nlm.nih.gov/articles/PMC11095902/
9. Safety Analysis of PARPi/ARPI Combinations Williams S, Kostos L, Azad AA. Abiraterone + olaparib in metastatic castration-resistant prostate cancer: tolerable, not toxic. AME Clin Trials Rev. 2025;3:38. https://actr.amegroups.org/article/view/10819/html
10. Comprehensive Olaparib Review (Monotherapy and Combination) Armstrong AJ, George DJ, McKay RR, Clarke NW, et al. Olaparib Monotherapy or in Combination with Abiraterone for the Treatment of Patients with mCRPC and a BRCA Mutation. Targeted Oncol. 2025. https://link.springer.com/article/10.1007/s11523-025-01146-4
11. AMPLITUDE Trial — PARPi Combination in Earlier Disease Stage (mHSPC) Chi KN, et al. Niraparib and abiraterone acetate plus prednisone for HRR-deficient metastatic castration-sensitive prostate cancer: a randomized phase 3 trial. Nat Med. 2025. https://www.nature.com/articles/s41591-025-03961-8
12. ASCO GU 2024 BRCAAway Commentary UroToday. ASCO GU 2024: BRCAAway — A Randomized Phase 2 Trial of Abiraterone, Olaparib, or Abiraterone + Olaparib in Patients with mCRPC Bearing HRR Mutations. Written by Zachary Klaassen, MD, MSc. https://www.urotoday.com/conference-highlights/asco-gu-2024/asco-gu-2024-prostate-cancer/149326
13. ASCO Daily News on BRCAAway ASCO Daily News. BRCAAway: Upfront Abiraterone/Olaparib Is More Effective Than Either Agent Alone or in Sequence in HRR-Mutated mCRPC. https://dailynews.ascopubs.org/do/brcaaway-upfront-abiraterone-olaparib-more-effective-than-either-agent-alone-sequence
14. ClinicalTrials.gov — BRCAAway Registration NCT03012321. https://clinicaltrials.gov/study/NCT03012321
This article is prepared for informational purposes for members of the Informed Prostate Cancer Support Group (IPCSG). It is not a substitute for individual medical advice. Please discuss all treatment decisions with your oncologist and, where possible, seek care at a center with expertise in advanced prostate cancer and genetic testing.
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