| Pharmacotherapeutic group: Protein kinase inhibitor, ATC code: L01XE07This medicinal product has been authorised under a so-called conditional approval scheme.This means that further evidence on this medicinal product is awaited.The European Medicines Agency (EMA) will review new information on the product every year and this SPC will be updated as necessary.The European Medicines Agency has waived the obligation to submit the results of studies with Tyverb in all subsets of the paediatric population in the treatment of breast carcinoma (see section 4.2 for information on paediatric use). Mechanism of action Lapatinib, a 4-anilinoquinazoline, is an inhibitor of the intracellular tyrosine kinase domains of both EGFR (ErbB1) and of HER2 (ErbB2) receptors (estimated Kiapp values of 3nM and 13nM, respectively) with a slow off-rate from these receptors (half-life greater than or equal to 300 minutes). Lapatinib inhibits ErbB-driven tumour cell growth in vitro and in various animal models. The growth inhibitory effects of lapatinib were evaluated in trastuzumab-conditioned cell lines. Lapatinib retained significant activity against breast cancer cell lines selected for long-term growth in trastuzumab-containing medium in vitro. Clinical studies Combination treatment with Tyverb and capecitabine The efficacy and safety of Tyverb in combination with capecitabine in breast cancer patients with good performance status was evaluated in a randomised, phase III trial. Patients eligible for enrolment had HER2-overexpressing, locally advanced or metastatic breast cancer, progressing after prior treatment that included taxanes, anthracyclines and trastuzumab. LVEF was evaluated in all patients (using echocardiogram or MUGA) prior to initiation of treatment with Tyverb to ensure baseline LVEF was within the institutions normal limits. In the clinical trial LVEF was monitored at approximately eight week intervals during treatment with Tyverb to ensure it did not decline to below the institutions lower limit of normal. The majority of LVEF decreases (greater than 60 %) were observed during the first nine weeks of treatment, however limited data was available for long term exposure.Patients were randomised to receive either Tyverb 1250 mg once daily (continuously) plus capecitabine (2000 mg/m2/day on days 1-14 every 21 days), or to receive capecitabine alone (2500 mg/m2/day on days 1-14 every 21 days). The primary endpoint was time to progression (TTP). Assessments were undertaken by the study investigators and by an independent review panel, blinded to treatment. The study was halted based on the results of a pre-specified interim analysis that showed an improvement in TTP for patients receiving Tyverb plus capecitabine. An additional 75 patients were enrolled in the study between the time of the interim analysis and the end of the enrolment. Investigator analysis on data at the end of enrolment is presented in Table 1.Table 1 Time to Progression data from Study EGF100151 (Tyverb / capecitabine) | | Investigator assessment | Tyverb (1,250 mg/day)+ capecitabine (2,000 mg/m2/day) | Capecitabine (2,500 mg/m2/day) | (N = 198) | (N = 201) | Number of TTP events | 121 | 126 | Median TTP, weeks | 23.9 | 18.3 | Hazard Ratio |
0.72 | (95% CI) |
(0.56, 0.92) | p value |
0.008 | The independent assessment of the data also demonstrated that Tyverb when given in combination with capecitabine significantly increased time to progression (Hazard Ratio 0.57 [95 % Cl 0.43, 0.77] p=0.0001) compared to capecitabine alone.Results of an updated analysis of the overall survival data to 28 September 2007 are presented in Table 2.Table 2 Overall survival data from Study EGF100151 (Tyverb / capecitabine) | | Tyverb (1,250 mg/day)+ capecitabine (2,000 mg/m2/day) | Capecitabine (2,500 mg/m2/day) | | | (N = 207) | (N = 201) | Number of subjects who died | 148 | 154 | Median overall survival, weeks | 74.0 | 65.9 | Hazard Ratio |
0.9 | (95% CI) |
(0.71, 1.12) | p value |
0.3 | On the combination arm, there were 4 (2%) progressions in the central nervous system as compared with the 13 (6%) progressions on the capecitabine alone arm.Combination treatment with Tyverb and letrozole Tyverb has been studied in combination with letrozole for the treatment of postmenopausal women with hormone receptor-positive (oestrogen receptor [ER] positive and / or progesterone receptor [PgR] positive) advanced or metastatic breast cancer.The Phase III study (EGF30008) was randomised, double-blind, and placebo controlled. The study enrolled patients who had not received prior therapy for their metastatic disease. The period of enrolment to the trial (December 2003 December 2006) preceded the adoption of trastuzumab in combination with an aromatase inhibitor. A comparative study between lapatinib and trastuzumab in this patient population has not been conducted.In the HER2-overexpressing population, only 2 patients were enrolled who had received prior trastuzumab, 2 patients had received prior aromatase inhibitor therapy, and approximately half had received tamoxifen.Patients were randomised to letrozole 2.5 mg once daily plus Tyverb 1500 mg once daily or letrozole with placebo. Randomisation was stratified by sites of disease and by time from discontinuation of prior adjuvant anti-oestrogen therapy. HER2 receptor status was retrospectively determined by central laboratory testing. Of all patients randomised to treatment, 219 patients had tumours overexpressing the HER2 receptor, and this was the pre-specified primary population for the analysis of efficacy. There were 952 patients with HER2-negative tumours, and a total of 115 patients whose tumour HER2 status was unconfirmed (no tumour sample, no assay result, or other reason).In patients with HER2-overexpressing MBC, investigator-determined progression-free survival (PFS) was significantly greater with letrozole plus Tyverb compared with letrozole plus placebo. In the HER2-negative population, there was no benefit in PFS when letrozole plus Tyverb was compared with letrozole plus placebo (see Table 3).Table 3 Progression Free Survival data from Study EGF30008 (Tyverb / letrozole) | | HER2-Overexpressing Population | HER2-Negative Population | N = 111 | N = 108 | N = 478 | N = 474 | Tyverb 1500 mg / day + Letrozole 2.5 mg /day | Letrozole 2.5 mg /day + placebo | Tyverb 1500 mg / day + Letrozole 2.5 mg /day | Letrozole 2.5 mg /day + placebo
| Median PFS, weeks (95% CI) | 35.4 (24.1, 39.4) | 13.0 (12.0, 23.7) | 59.7 (48.6, 69.7) | 58.3 (47.9, 62.0) | Hazard Ratio |
0.71 (0.53, 0.96) |
0.90 (0.77, 1.05) | P-value |
0.019 |
0.188 | Objective Response Rate (ORR) | 27.9% | 14.8% | 32.6% | 31.6% | Odds Ratio |
0.4 (0.2, 0.9) |
0.9 (0.7, 1.3) | P-value |
0.021 |
0.26 | Clinical Benefit Rate (CBR) | 47.7% | 28.7% | 58.2% | 31.6% | Odds Ratio |
0.4 (0.2, 0.8) |
1.0 (0.7, 1.2) | P-value |
0.003 |
0.199 |
CI= confidence interval HER2 overexpression = IHC 3+ and/or FISH positive; HER2 negative = IHC 0, 1+ or 2+ and/or FISH negative Clinical Benefit Rate was defined as complete plus partial response plus stable disease for 6 months. At the time of analysis, the overall survival data were not mature and there was no significant difference between treatment groups (Tyverb + letrozole combination HR= 0.77 [95 %CI 0.52-1.14] p=0.185). However, no negative effect on overall survival was apparent. | |