Preliminary results of DESTINY-Lung02 show strong efficacy with trastuzumab deruxtecan (T-DXd). Overall response rate (ORR) was about 50%, with duration of response of 16.8 months.
This is now FDA-approved and is an available therapy for patients with ERBB2 mutations after 1st line platinum-based chemo +/- immunotherapy. This is preferred over traditional trastuzumab or afatinib. Interestingly, some responses were seen in the ERBB2-negative patients who had over-expression by IHC. Please continue to sequence your patients and enroll in targeted therapy trials.
Trastuzumab deruxtecan (T-DXd) 5.4 and 6.4 mg/kg showed robust antitumor activity in multiple cancer indications; however, T-DXd 5.4 mg/kg has not been evaluated in patients with previously treated human epidermal growth factor receptor 2–mutant (HER2m; defined as single-nucleotide variants and exon 20 insertions) metastatic non–small-cell lung cancer (mNSCLC).
DESTINY-Lung02, a blinded, multicenter, phase II study, investigated T-DXd 5.4 mg/kg once every 3 weeks for the first time in previously treated (platinum-containing therapy) patients with HER2m mNSCLC and further assessed T-DXd 6.4 mg/kg once every 3 weeks in this population. The primary end point was confirmed objective response rate (ORR) per RECIST v1.1 by blinded independent central review.
One hundred fifty-two patients were randomly assigned 2:1 to T-DXd 5.4 or 6.4 mg/kg once every 3 weeks. As of December 23, 2022, the median duration of follow-up was 11.5 months (range, 1.1-20.6) with 5.4 mg/kg and 11.8 months (range, 0.6-21.0) with 6.4 mg/kg. Confirmed ORR was 49.0% (95% CI, 39.0 to 59.1) and 56.0% (95% CI, 41.3 to 70.0) and median duration of response was 16.8 months (95% CI, 6.4 to not estimable [NE]) and NE (95% CI, 8.3 to NE) with 5.4 and 6.4 mg/kg, respectively. Median treatment duration was 7.7 months (range, 0.7-20.8) with 5.4 mg/kg and 8.3 months (range, 0.7-20.3) with 6.4 mg/kg. Grade ≥ 3 drug-related treatment-emergent adverse events occurred in 39 of 101 (38.6%) and 29 of 50 (58.0%) patients with 5.4 and 6.4 mg/kg, respectively. 13 of 101 (12.9%) and 14 of 50 (28.0%) patients had adjudicated drug-related interstitial lung disease (2.0% grade ≥ 3 in each arm) with 5.4 and 6.4 mg/kg, respectively.
T-DXd demonstrated clinically meaningful responses at both doses. Safety profile was acceptable and generally manageable, favoring T-DXd 5.4 mg/kg.
Patients were treated with thoracic and extrathoracic radiation to oligometastatic sites and it seems to help with improving survival, something to consider especially with SBRT now. Do our radiation oncologists have additional input?
Improved progression-free survival (PFS), now we have osimertinib and ramucirumab, amivantamab and Lazertinib (PFS 24.8 vs 23 months but NOT head to head).
Very thought-provoking review of immune checkpoint blockade therapy and strategies to possibly de-escalate therapy in the future. Could we reduce doses, extend dose intervals or diminish the duration of treatment? There is some (low-level) data supporting these ideas. However, ongoing prospective studies, mostly being done in countries with nationalized systems, will be informative on these topics. Expect interest in this topic to increase in a couple of years.
Positive trial for the newest ADC on the block, Dato-DXd, is an ADC that delivers a topoisomerase I inhibitor payload via a TROP2 antibody. PFS was not impressive but favored DDxd at 4.4 vs 3.7 months in the docetaxel arm. This drug is now approved in metastatic breast cancer.
Pembrolizumab in addition to chemotherapy DID NOT help, recall now we have new approval for those patients (datopotamab).
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