Brief Report: Combination of Osimertinib and Dacomitinib to Mitigate Primary and Acquired Resistance in EGFR-Mutant Lung Adenocarcinomas

PURPOSE

Primary and acquired resistance to osimertinib remain significant challenges for patients with EGFR-mutant lung cancers. Acquired EGFR alterations such as EGFR T790M or C797S mediate resistance to EGFR tyrosine kinase inhibitors (TKI) and combination therapy with dual EGFR TKIs may prevent or reverse on-target resistance.

PATIENTS AND METHODS

We conducted two prospective, phase I/II trials assessing combination osimertinib and dacomitinib to address on-target resistance in the primary and acquired resistance settings. In the initial therapy study, patients received dacomitinib and osimertinib in combination as initial therapy. In the acquired resistance trial, dacomitinib with or without osimertinib was administered to patients with EGFR-mutant lung cancers with disease progression on osimertinib alone and evidence of an acquired EGFR second-site mutation.

RESULTS

Cutaneous toxicities occurred in 93% (any grade) of patients and diarrhea in 72% (any grade) with the combination. As initial therapy, the overall response to the combination was 73% [95% confidence interval (CI), 50%-88%]. No acquired secondary alterations in EGFR were observed in any patients at progression. In the acquired resistance setting, the overall response was 14% (95% CI, 1%-58%).

CONCLUSIONS

We observed no acquired secondary EGFR alterations with dual inhibition of EGFR as up-front treatment, but this regimen was associated with greater toxicity. The combination was not effective in reversing acquired resistance after development of a second-site acquired EGFR alteration. Our study highlights the need to develop better strategies to address on-target resistance in patients with EGFR-mutant lung cancers.

Pilot Study of Dacomitinib for Patients With Metastatic EGFR-Mutant Lung Cancers With Disease Progression After Initial Treatment With Osimertinib

Patients with EGFR-mutant lung cancer have no approved targeted therapies after disease progression on first-line osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). Preclinical studies suggest that tumors with both EGFR-sensitizing alteration and acquired second-site EGFR resistance alterations after treatment with osimertinib retain sensitivity to second-generation EGFR TKIs. We hypothesized that dacomitinib, a pan-human epidermal growth factor receptor TKI, may be effective in this setting.

METHODS

In this phase II study, patients who had progressed on first-line osimertinib were treated with dacomitinib 45 mg orally daily until disease progression or intolerability. The primary end point was objective response rate.

RESULTS

We enrolled 12 patients. Two partial responses were documented (17% objective response rate; 95% CI, 5 to 45). The median progression-free survival was 1.8 months (95% CI, 1.6 to not reached). One patient with an original sensitizing EGFR G719A mutation and one patient without molecular testing available had partial responses, whereas 0 of the 3 patients with second-site acquired EGFR resistance mutations (two C797S and one G724S) met the response criteria. The patient with EGFR G719A has an ongoing response at 17 months, which exceeds prior time on osimertinib (11 months).

CONCLUSION

In the first trial evaluating a second-generation EGFR TKI after first-line third-generation osimertinib, we found that dacomitinib after disease progression on osimertinib has limited benefit.

Clinical outcomes of systemic therapy for patients with deep fibromatosis (desmoid tumor)

BACKGROUND

In the current study, the authors examined the outcomes of patients with desmoid tumors who received systemic therapy at a single institution to provide a basis for the examination of newer agents.

METHODS

Records of patients with desmoid tumors who were treated with chemotherapy at the study institution were reviewed. The activity of nonsteroidal anti-inflammatory drugs was not addressed. Patients without measurable disease and those receiving therapy could not be documented, and those receiving prophylactic therapy were excluded.

RESULTS

A total of 68 patients received 157 lines of therapy. At the time of last follow-up, 9 patients had died, 7 of progressive disease. The cohort was 62% female, with a median age of 32.5 years. Approximately 32% of the patients had Gardner syndrome. The median follow-up was 63 months, and patients received a median of 2 lines of therapy. An intra-abdominal primary tumor location was the most common (44%). The greatest Response Evaluation Criteria in Solid Tumors (RECIST) response rate was observed with anthracyclines and hormonal therapy and the lowest response was noted with single-agent dacarbazine/temozolomide or tyrosine kinase inhibitors, principally imatinib. On multivariate analysis, macroscopic nodular morphology and the presence of Gardner syndrome were the only tumor factors found to be associated with a greater time to disease progression.

CONCLUSIONS

Compared with other agents, antiestrogens and anthracycline-containing regimens appear to be associated with a higher radiological response rate against desmoid tumors. Systemic therapy can be successful in patients with desmoid tumors, and is a viable option in lieu of morbid or disabling surgery.

Comparison of risk-adjustment models using administrative or clinical data for outcome prediction in patients after myocardial infarction or coronary bypass surgery in Korea

OBJECTIVE

The objectives of this study were to compare the performance indicators of risk-adjustment models based on administrative and clinical data in Korea, and to assess whether administrative data alone is useful for comparing quality of care.

METHODS

Outcome was defined as death within 30 days of discharge. For administrative data, the risk factors were; age, sex, and 11 past histories and two past major procedures, which were retrospectively chased in National Health Insurance database using patient Identification Number. For clinical data, the severity score of the three risk-adjustment measures [MedisGroups, Disease Staging (DS) and Computerized Severity Index (CSI)] was used as the independent predictors of 30-day mortality. Risk-adjustment models were developed by logistic regression analysis for 13,885 Acute Myocardial Infarction (AMI) and 2115 Coronary Artery Bypass Graft (CABG) patients based on administrative data and for 208 AMI patients and 478 CABG patients using clinical data. Performances of models were examined using c-statistic and Hosmer-Lemeshow statistic.

RESULTS

The results obtained showed the superiority of the clinical model. For AMI, the c-statistic of the administrative model was 0.696, and those of the CSI, DS and MedisGroups models were 0.772, 0.861 and 0.988 respectively. For CABG, the c-statistic of the administrative model was 0.568, and those of the CSI, DS and MedisGroups models were 0.665, 0.731 and 0.816 respectively.

CONCLUSION

Our results indicate that risk-adjustment model only using administrative data are probably not useful for assessing quality of care in Korea.