The high-impact research unveiled as ASCO’s plenary session means it is always highly anticipated and well attended. This year, 4 out of the 20 late-breaking abstracts at the conference were included in the plenary session.
Remarkably, overall survival gains were detailed in three of the four late breaking abstracts included in the plenary session (LBA1, LBA2, and LBA3), and surprisingly none of the abstracts selected included immune checkpoint inhibitors - a refreshing reminder that immunotherapy alone is likely not the answer to conquering cancer. Below is a summary of the key take-home messages of each of the late breaking abstracts.
Late Breaking Abstract 1 (LBA1): Prospective pooled analysis of six phase III trials investigating duration of adjuvant oxaliplatin-based therapy (3 vs 6 months) for patients with stage III colon cancer: The IDEA collaboration1:
- Oxaliplatin is associated with cumulative dose-dependent neurotoxicity resulting in low treatment compliance. The IDEA collaborated reported that 3-month treatment compared to 6-month treatment duration results in a higher treatment compliance (90% vs. 71% with FOLFOX and 86% vs. 65% with CAPOX).
- The rate of disease-free survival at 3 years was slightly lower with 3 months of chemotherapy vs. 6 months of chemotherapy (74.6% vs 75.5%). However, when high- and low-risk groups were analyzed, 3 months of treatment was non-inferior to 6 months of treatment for low-risk patients (T1-3 N1).
- The type of chemotherapy regimen selected affected the difference in 3-year disease-free survival between the 3-month and 6-month treatment duration (75.9% vs. 74.8% with CAPOX and 73.6% vs. 76.0% with FOLFOX).
- The rate of ≥ grade 2 (defined as clinically meaningful) nerve damage differed depending on the type of chemotherapy regimen received, but unsurprisingly was higher for people who received 6 months vs 3 months of chemotherapy (45% vs 15% with FOLFOX and 48% vs 17% with CAPOX).
This presentation highlighted that low-risk patients can achieve greater efficacy outcomes by halving the duration of adjuvant treatment (in the case of CAPOX). Ultimately this means shorter duration of treatment without loss of efficacy, benefiting both patients and health care resources.
Late Breaking Abstract 2 (LBA2): Overall survival results of a randomized trial assessing patient-reported outcomes for symptom monitoring during routine cancer treatment2:
- Extraordinarily, MOS was significantly improved when patients reported their symptoms. MOS was 5 months longer for patients in the self-reporting arm compared with standard care (31.2 vs. 26.0 months; p = 0.03). This translated to a 5-year absolute survival benefit of 8%.
- Compared to the standard symptom monitoring arm, 31% more patients in the self-reporting arm experienced quality of life benefits (p<0.001).
Treatment is increasingly becoming patient centric, and this presentation displayed the positive impact empowering patients often has on treatment outcomes. The abstract discussant Dr Monika Krzyzanowska noted that “proactive symptom monitoring should be considered the new standard of care,” and she called this a “practice-changing study.” Unfortunately, it will prove challenging, particularly financially, to implement this into practice immediately, however it seems likely that self-reporting will become more common in clinical practice in the coming years.
Late Breaking Abstract 3 (LBA3): LATITUDE: A phase III, double-blind, randomized trial of androgen deprivation therapy with abiraterone acetate plus prednisone or placebos in newly diagnosed high-risk metastatic hormone-naïve prostate cancer3:
- After a median follow-up of 30.4 months at a planned interim analysis, the MOS was significantly longer in the abiraterone group than in the placebo group (not reached vs. 34.7 months; HR: 0.62; p = <0001). The OS rate reported at 3 years was 66% with abiraterone and prednisone, compared to only 49% without.
- There was also a statistically significant 53% risk reduction of radiographic progression or death for the ADT plus abiraterone group versus the ADT plus placebo group (33.0 months versus 14.8 months (95% CI, P<0.0001).
These data highlight the importance of timing; starting abiraterone earlier appears to make a considerable difference to patient outcomes. While further evaluation is required - ideally in the form of a head-to-head comparison to determine if ADT plus abiraterone provides similar or greater benefits compared with ADT plus docetaxel – many attendees took to Twitter during, and after the session, detailing this as a “practice-changing” discovery.
Late Breaking Abstract 4 (LBA4): OlympiAD: Phase III trial of olaparib monotherapy versus chemotherapy for patients with HER2-negative metastatic breast cancer and a germline BRCA mutation4:
- Patients in the olaparib arm achieved a PFS of 7 months compared with 4.2 months for patients in the chemotherapy arm. The drug also reduced the chance of disease progression by 42%, thus becoming the first targeted agent to show a significant clinical benefit in metastatic germline BRCA1/2-mutated breast cancer patients.
These data are impressive, and based on these positive results AstraZeneca have announced that they intend to work with regulatory authorities to make olaparib available to patients with BRCA1/2-mutated breast cancer in the near future. However, I couldn’t help feeling that this data will not have such a far reaching impact compared to the prior presentations given during the plenary session, in part due to the relatively small number of breast cancer patients who harbor BRCA1/2 mutations.
One thing that struck me during ASCO’s plenary session was that out of the four late breaking abstracts presented, only one detailed success of a drug in a new indication (LBA4, olaparib in breast cancer), the other presentations highlighted the importance of continual evaluation and optimization of approved agents.
- Prospective pooled analysis of six phase III trials investigating duration of adjuvant (adjuv) oxaliplatin-based therapy (3 vs 6 months) for patients (pts) with stage III colon cancer (CC): The IDEA (International Duration Evaluation of Adjuvant chemotherapy) collaboration. Journal of Clinical Oncology; 35, 2017 (suppl; abstr LBA1)
- Overall survival results of a randomized trial assessing patient-reported outcomes for symptom monitoring during routine cancer treatment. Journal of Clinical Oncology. 35, 2017 (suppl; abstr LBA2)
- Fizazi K, et al. Abiraterone plus Prednisone in Metastatic, Castration-Sensitive Prostate Cancer. New England Journal of Medicine. June 4, 2017.
- Robson ME, et al. Olaparib for Metastatic Breast Cancer in Patients with Germline BRCA Mutation. New England Journal of Medicine. June 4, 2017.