Off-label despite high-level evidence: a clinical practice review of commonly used off-patent cancer medicines

INTRODUCTION

Off-label use of medicines is generally discouraged. However, several off-patent, low-cost cancer medicines remain off-label for indications in which they are commonly used in daily practice, supported by high-level evidence based on results of phase III clinical trials. This discrepancy may generate prescription and reimbursement obstacles as well as impaired access to established therapies.

METHODS

A list of cancer medicines that remain off-label in specific indications despite the presence of high-level evidence was generated and subjected to European Society for Medical Oncology (ESMO) expert peer review to assess for accountability of reasonableness. These medicines were then surveyed on approval procedures and workflow impact. The most illustrative examples of these medicines were reviewed by experts from the European Medicines Agency to ascertain the apparent robustness of the supporting phase III trial evidence from a regulatory perspective.

RESULTS

A total of 47 ESMO experts reviewed 17 cancer medicines commonly used off-label in six disease groups. Overall, high levels of agreement were recorded on the off-label status and the high quality of data supporting the efficacy in the off-label indications, often achieving high ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS) scores. When prescribing these medicines, 51% of the reviewers had to implement a time-consuming process associated with additional workload, in the presence of litigation risks and patient anxiety. Finally, the informal regulatory expert review identified only 2 out of 18 (11%) studies with significant limitations that would be difficult to overcome in the context of a potential marketing authorisation application without additional studies.

CONCLUSIONS

We highlight the common use of off-patent essential cancer medicines in indications that remain off-label despite solid supporting data as well as generate evidence on the adverse impact on patient access and clinic workflows. In the current regulatory framework, incentives to promote the extension of indications of off-patent cancer medicines are needed for all stakeholders.

Preferences about Future Alzheimer's Disease Treatments Elicited through an Online Survey Using the Threshold Technique

BACKGROUND

Treatments aiming at slowing down the progression of Alzheimer's disease (AD) may soon become available. However, information about the risks that people are willing to accept in order to delay the progression of the disease is limited.

OBJECTIVE

To determine the trade-offs that individuals are willing to make between the benefits and risks of hypothetical treatments for AD, and the extent to which these trade-offs depend on individuals' characteristics and beliefs about medicines.

DESIGN

Online, cross-sectional survey study.

SETTING

Population in the UK. Public link to the survey available at the websites of Alzheimer's Research UK and Join Dementia Research.

PARTICIPANTS

Everyone self-reported ≥18 years old was eligible to participate. A total of 4384 people entered the survey and 3658 completed it.

MEASUREMENTS

The maximum acceptable risks (MARs) of participants for moderate and severe adverse events in exchange for a 2-year delay in disease progression. The risks were expressed on ordinal scales, from <10% to ≥50%, above a pre-existing risk of 30% for moderate adverse events and 10% for severe adverse events. We obtained the population median MARs using log-normal survival models and quantified the effects of individuals' characteristics and beliefs about medicines in terms of acceleration factors.

RESULTS

For the moderate adverse events, 26% of the participants had a MAR ≥50%, followed by 25% of the participants with a MAR of 10 to <20%, giving an estimated median MAR of 25.4% (95% confidence interval [CI] 24.5 to 26.3). For the severe adverse events, 43% of the participants had a MAR <10%, followed by 25% of the participants with a MAR of 10 to <20%, resulting in an estimated median MAR of 12.1% (95%CI 11.6 to 12.5). Factors that were associated with the individuals' MARs for one or both adverse events were age, gender, educational level, living alone, and beliefs about medicines. Whether or not individuals were living with memory problems or had experience as a caregiver had no effect on the MARs for any of the adverse events.

CONCLUSION

Trade-offs between benefits and risks of AD treatments are heterogeneous and influenced by individuals' characteristics and beliefs about medicines. This heterogeneity should be acknowledged during the medicinal product decision-making in order to fulfil the needs of the various subpopulations.

The EMA assessment of avapritinib in the treatment of gastrointestinal stromal tumours harbouring the PDGFRA D842V mutation

Avapritinib is a protein kinase inhibitor designed to selectively inhibit oncogenic KIT and platelet-derived growth factor receptor alpha (PDGFRA) mutants by targeting the active conformation of the kinase. On 24 September 2020, a marketing authorisation valid through the European Union was issued for avapritinib as treatment of adult patients with unresectable or metastatic gastrointestinal stromal tumours (GIST) harbouring the PDGFRA D842V mutation. The drug was evaluated in an open-label, phase I, first-in-human, dose-escalation, open-label study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and efficacy of avapritinib in adults with unresectable or metastatic GIST. The benefit of avapritinib was observed in patients with GIST harbouring the PDGFRA D842V mutation. The overall response rate was 95% (95% confidence interval 82.3%-99.4%), with a median duration of response of 22.1 months (95% confidence interval 14.1-not estimable months). The most common adverse events were nausea, fatigue, anaemia, periorbital and face oedema, hyperbilirubinaemia, diarrhoea, vomiting, increased lacrimation, and decreased appetite. Most of the reported cognitive effects were mild memory impairment. Rarer events were cases of severe encephalopathy and intracranial or gastrointestinal bleeding. The aim of this manuscript is to summarise the scientific review of the application leading to regulatory approval in the European Union.

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Avapritinib is a protein kinase inhibitor designed to inhibit oncogenic KIT and PDGFRA mutants.

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A marketing authorisation was issued for avapritinib as treatment of patients with GIST harbouring the PDGFRA D842V mutation.

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The overall response rate was 95% (95% CI 82.3-99.4), with a median duration of response of 22.1 months (95% CI 14.1-NE).

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The most common adverse events were nausea, fatigue, anaemia, periorbital and face oedema, hyperbilirubinaemia and diarrhoea.

The EMA assessment of pembrolizumab as monotherapy for the first-line treatment of adult patients with metastatic microsatellite instability-high or mismatch repair deficient colorectal cancer

On 21 January 2021, the European Commission amended the marketing authorisation granted for pembrolizumab to include the first-line treatment of microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic colorectal cancer (mCRC) in adults. The recommended dose of pembrolizumab was either 200 mg every 3 weeks or 400 mg every 6 weeks by intravenous infusion. Pembrolizumab was evaluated in a phase III, open-label, multicentre, randomised trial versus standard of care (SOC: FOLFOX6/FOLFIRI alone or in combination with bevacizumab/cetuximab) as first-line treatment of locally confirmed mismatch repair-deficient or microsatellite instability-high stage IV CRC. Subjects randomised to the SOC arm had the option to crossover and receive pembrolizumab once disease progressed. Both progression-free survival (PFS) and overall survival were primary endpoints. Pembrolizumab showed a statistically significant improvement in PFS compared with SOC, with a hazard ratio of 0.60 [95% confidence interval (CI): 0.45-0.80], P = 0.0002. Median PFS was 16.5 (95% CI: 5.4-32.4) versus 8.2 (95% CI: 6.1-10.2) months for the pembrolizumab versus SOC arms, respectively. The most frequent adverse events in patients receiving pembrolizumab were diarrhoea, fatigue, pruritus, nausea, increased aspartate aminotransferase, rash, arthralgia, and hypothyroidism. Having reviewed the data submitted, the European Medicines Agency’s (EMA’s) Committee for Medicinal Products for Human Use (CHMP) considered that the benefit–risk balance was positive. This is the first time the CHMP has issued an opinion for a target population defined by DNA repair deficiency biomarkers. The aim of this manuscript is to summarise the scientific review of the application leading to regulatory approval in the European Union.

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The European Commission amended the marketing authorisation granted for pembrolizumab to include the first-line treatment of MSI-H/dMMR mCRC.

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Pembrolizumab showed a significant improvement in PFS compared with standard of care (HR 0.60, 95% CI: 0.45-0.80, P = 0.0002).

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The most frequent adverse events with pembrolizumab were diarrhoea, fatigue, pruritus, nausea, increased aspartate aminotransferase, rash, and arthralgia.

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This is the first time the CHMP has issued an opinion for a target population defined by DNA repair deficiency biomarkers.

The European Medicines Agency review of entrectinib for the treatment of adult or paediatric patients with solid tumours who have a neurotrophic tyrosine receptor kinase gene fusions and adult patients with non-small-cell lung cancer harbouring ROS1 rearrangements

Entrectinib is an inhibitor of the tyrosine kinases TRKA, TRKB, TRKC [all together known as neurotrophic tyrosine receptor kinases (NTRKs)], ROS1 and anaplastic lymphoma kinase (ALK). On 31 July 2020, a conditional marketing authorisation valid through the European Union (EU) was issued for entrectinib for the treatment of adult and paediatric patients 12 years of age and older with NTRK fusion-positive solid tumours that are locally advanced, metastatic or where surgical resection is likely to result in severe morbidity, and who have not received a prior NTRK inhibitor and have no satisfactory therapy; and also for adult patients with ROS1-positive non-small-cell lung cancer (NSCLC) not previously treated with ROS1 inhibitors. The submission was based on three open-label, multicentre, phase I studies (ALKA, STARTRK-1 and STARTRK-NG) and one phase II study (STARTRK-2). In patients with NTRK-positive solid tumours, the objective response rate (ORR) was 63.5% [95% confidence interval (CI) 51.5% to 74.4%] and the median duration of response (DOR) was 12.9 months (95% CI 9.3-not estimable). In patients with ROS1-positive NSCLC, the ORR was 67.1% (95% CI 59.25% to 74.27%) and the median DOR was 15.7 months (95% CI 13.9-28.6 months). The most frequent adverse events were dysgeusia, fatigue, dizziness, constipation, diarrhoea, nausea, increased weight, paraesthesia, increased creatinine, myalgia, peripheral oedema, vomiting, arthralgia, anaemia and increased AST. The aim of this manuscript is to summarise the scientific review of the application leading to regulatory approval of entrectinib in the EU.

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Entrectinib was granted a CMA for the treatment of patients older than 12 years with NTRK fusion-positive solid tumours.

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A CMA was also issued for the treatment of adult patients with ROS1+ NSCLC not previously treated with ROS1 inhibitors.

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The submission, reviewed in this paper, was based on three open-label, multicentre, phase I studies and one phase II study.

The EMA review of trastuzumab emtansine (T-DM1) for the adjuvant treatment of adult patients with HER2-positive early breast cancer

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate of trastuzumab [a monoclonal antibody against human epidermal growth factor receptor 2 (HER2)] and DM1 (an inhibitor of tubulin polymerisation). It was initially approved in the European Union for the treatment of adult patients with HER2-positive unresectable locally advanced or metastatic breast cancer (BC) who had previously received trastuzumab and taxanes. On 18 December 2019, a variation of the marketing authorisation was approved extending this use to the adjuvant therapy of adult patients with HER2-positive early BC who have residual invasive disease in the breast and/or lymph nodes after neoadjuvant taxane-based and HER2-targeted therapy. A phase III randomised, multicentre, open-label trial compared T-DM1 with trastuzumab as adjuvant therapy in patients with HER2-positive early BC who had received preoperative chemotherapy and HER2-targeted therapy followed by surgery, with a finding of invasive residual disease in the breast and/or axillary lymph nodes. The study met its primary endpoint by showing an increased 3-year invasive disease-free survival rate in the T-DM1 arm (88.3%) compared with the trastuzumab arm (77.0%), with an unstratified hazard ratio of 0.50 (95% confidence interval: 0.39-0.64). There was a higher incidence of hepatotoxicity (37.3% versus 10.6%), thrombocytopenia (28.5% versus 2.4%), peripheral neuropathy (32.3% versus 16.9%), haemorrhage (29.2% versus 9.6%) and pulmonary toxicity (2.8% versus 0.8%) in the T-DM1 arm compared with the control arm. The aim of this manuscript was to summarise the scientific review of the application leading to regulatory approval of this additional indication in the European Union.

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T-DM1 was approved for the adjuvant therapy of HER2+ early BC not in pathological complete response after taxanes + anti-HER2 neoadjuvant therapy.

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A phase III randomised trial revealed an increased 3-year invasive disease-free survival rate in patients receiving T-DM1 compared with trastuzumab.

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Patients receiving T-DM1 experienced more hepatotoxicity, thrombocytopenia, neuropathy, bleeding and lung toxicity.

The European Medicines Agency review of the initial application of atezolizumab and the role of PD-L1 expression as biomarker for checkpoint inhibitors

Immune checkpoint inhibitors have revolutionised cancer therapeutics. Translational research evaluating the role of biomarkers is essential to identify the ideal target population for these drugs. From a regulatory perspective, the identification of biomarkers and diagnostic assays is strongly encouraged by the European Medicines Agency (EMA). The aim of this article is to analyse the role of programmed death-ligand 1 (PD-L1) expression as a predictive biomarker in relation to the data submitted for the initial assessment of atezolizumab, a monoclonal antibody targeting human PD-L1. On 20 July 2017, atezolizumab was granted a marketing authorisation valid throughout the European Union (EU) for adult patients with (i) locally advanced or metastatic non-small-cell lung cancer (NSCLC) after chemotherapy and (ii) locally advanced or metastatic urothelial carcinoma (UC) after chemotherapy or cisplatin-ineligibility. Initially, these indications were not restricted by the level of PD-L1 expression, but preliminary data from an ongoing phase III trial in patients with UC led to a restriction in the UC indication to cisplatin-ineligible patients whose tumours have ≥5% PD-L1 expression. Still, the role of PD-L1 expression as predictive biomarker for atezolizumab therapy remains inconclusive and further research is needed. Data in this paper came from the scientific review leading to the initial regulatory approval of atezolizumab in the EU and its complementary application for indication (EMEA/H/C/004143/II/0010). The full scientific assessment report and product information are available on the EMA website (www.ema.europa.eu).

"Threshold-crossing": A Useful Way to Establish the Counterfactual in Clinical Trials?

A central question in the assessment of benefit/harm of new treatments is: how does the average outcome on the new treatment (the factual) compare to the average outcome had patients received no treatment or a different treatment known to be effective (the counterfactual)? Randomized controlled trials (RCTs) are the standard for comparing the factual with the counterfactual. Recent developments necessitate and enable a new way of determining the counterfactual for some new medicines. For select situations, we propose a new framework for evidence generation, which we call "threshold-crossing." This framework leverages the wealth of information that is becoming available from completed RCTs and from real world data sources. Relying on formalized procedures, information gleaned from these data is used to estimate the counterfactual, enabling efficacy assessment of new drugs. We propose future (research) activities to enable "threshold-crossing" for carefully selected products and indications in which RCTs are not feasible.

From adaptive licensing to adaptive pathways: delivering a flexible life-span approach to bring new drugs to patients

The concept of adaptive licensing (AL) has met with considerable interest. Yet some remain skeptical about its feasibility. Others argue that the focus and name of AL should be broadened. Against this background of ongoing debate, we examine the environmental changes that will likely make adaptive pathways the preferred approach in the future. The key drivers include: growing patient demand for timely access to promising therapies, emerging science leading to fragmentation of treatment populations, rising payer influence on product accessibility, and pressure on pharma/investors to ensure sustainability of drug development. We also discuss a number of environmental changes that will enable an adaptive paradigm. A life‐span approach to bringing innovation to patients is expected to help address the perceived access vs. evidence trade‐off, help de‐risk drug development, and lead to better outcomes for patients.

Clinical determinants of survival in patients with 5-fluorouracil-based treatment for metastatic colorectal cancer: results of a multivariate analysis of 3825 patients

BACKGROUND

Patients with metastatic colorectal cancer are usually offered systemic chemotherapy as palliative treatment. A multivariate analysis was performed in order to identify predictors and their constellation that allow a valid prediction of the outcome in patients treated with 5-fluorouracil (5-FU)-based therapy.

PATIENTS AND METHODS

A total of 3825 patients treated with 5-FU within 19 prospective randomised and three phase II trials were separated into learning (n = 2549) and validation (n = 1276) samples. Data were analysed by tree analysis using the recursive partition and amalgamation method (RECPAM). A predictor could only enter the RECPAM analysis if the number of patients with missing values was < 33.3% within a node, and the minimal node size was set to 50 patients. Twenty-three potential predictors were grouped into subsets of laboratory variables (11 parameters), tumour-related variables (seven parameters) and clinical variables (five parameters). In the first step, tree analysis was performed separately for each predictor subset. The selected prognostic parameters of the resulting partial models (the 'winners') were entered into the general model. The classification rule from the data of the learning set was applied to the independent validation set.

RESULTS

Winners of the subgroup analysis for laboratory variables were: platelets > or = 400 x 10(9)/l, alkaline phosphatase > or = 300 U/l, white blood cell (WBC) count > or = 10 x 10(9)/l and haemoglobin < 11 x 10(9)/l, and all predicted a worse outcome. Negative predictors within the subgroup of tumour parameters were: number of tumour sites more than one or more than two, presence of liver metastases or peritoneal carcinomatosis, which predicted a worse outcome. Furthermore, presence of lung metastases, a primary rectal cancer and presence of lymph node metastases all predicted a better outcome in the multivariate setting. Among the clinical parameters only performance status of ECOG 0 or 1 predicted better outcome. In the final regression tree, three risk groups could be identified: low risk group (n = 1111) with a median survival of 15 months for patients with ECOG 0/1 and only one tumour site; intermediate risk group (n = 904) with a median survival of 10.7 months for patients with ECOG 0/1 and more than one tumour site and alkaline phosphatase < 300 U/l or patients with ECOG > 1, WBC count < 10 x 10(9)/l and only one tumour site; high risk group (n = 534) with a median survival of 6.1 months for patients with ECOG 0/1 and more than one tumour site and alkaline phosphatase of > or = 300 U/l or patients with ECOG > 1 and more than one tumour site or WBC count > 10 x 10(9)/l. The median survival times for the good, intermediate and high risk groups in the validation sample were 14.7, 10.5 and 6.4 months, respectively.

CONCLUSIONS

Patients can be divided into at least three risk groups depending on the four baseline clinical parameters: performance status, WBC count, alkaline phosphatase and number of metastatic sites. Any molecular or biological marker should be validated against these clinical parameters and decisions for more or less intensive treatments may be studied separately in these three risk groups. Also, clinical trials should be stratified according to the three risk groups.

Candidate gene polymorphisms in cardiovascular disease: a comparative study of frequencies between a French and an Italian population

A multilocus assay was used to genotype up to 27 variable sites in 15 genes in French and Italian, presumed to be healthy populations (n=1480, n=162, respectively). These genes are involved in lipid metabolism (APOE, APOB, APOC3, CETP, LPL, PON), homocysteine metabolism (CBS, MTHFR), blood viscosity (Fibrinogen, FV), platelet aggregation (GpIIIa), leukocyte adhesion (SELE), and renin-angiotensin system (AT1R, ACE, AGT). Allele frequencies for all the markers were compared between the two populations. Five allele frequencies differed between the two European countries: APOB 71Ile (p < 0.001), SELE 98T (p < 0.001), SELE 128Arg (p < or = 0.01), APOE E4 (p < or = 0.01) and MTHFR 677T (p < or = 0.01), suggesting the existence of a north-south gradient in European allele frequencies. The other allele frequencies : APOC3 -482T, -455C, 1100T, 3175G, 3206G; LPL -93G, 9Asn, 291Ser; CETP 405Val; PON 192Arg; ACE Del; AGT 235Thr; AT1R 1166C; CBS 278Thr, GpIIIa P1A2; Fibrinogen -455A, FV 506Gln and SELE 554Phe, were similar between the two populations. They were also similar to those observed in other European countries.

Vinorelbine and mitomycin C in anthracycline-pretreated patients with advanced breast cancer

At present, there is no satisfactory treatment for advanced breast cancer patients who have become refractory to anthracyclines. Vinca alkaloids and mitomycin C (MMC) are among the drugs most frequently used in this setting. Recently, vinorelbine (VNR) has been reported to be highly active in advanced breast cancer. Sixty advanced breast cancer patients previously treated with anthracyclines have been exposed to VNR 25 mg/m2 i.v. on days 1 and 8, and MMC 10 mg/m2 i.v. on day 1, with cycles repeated every 4 weeks. There were 3 complete and 21 partial responses for an overall response rate of 40% (CI 95%: 28-52%). Median duration of response and median survival were 7 and 10 months, respectively. Myelosuppression was the dose-limiting toxicity, but it was generally mild to moderate. Although this combination appears to be effective and well tolerated, every effort should be made to further improve treatment results in anthracycline-pretreated advanced breast cancer.

Intrapatient comparison of single-agent epirubicin with or without lonidamine in metastatic breast cancer

The aim of this study was to determine if lonidamine (LND) supplementation to single-agent epirubicin (EPI) could reverse anthracycline resistance in patients with metastatic breast cancer. 45 patients with metastatic breast cancer were treated with EPI 120 mg/m2 by intravenous (i.v.) bolus every 3 weeks. Patients who progressed were given the same chemotherapy regimen on day 4 in combination with oral LND, 150 mg on day 1, 300 mg on day 2 and 450 mg on days 3-5. Among the 40 evaluable patients, 6 complete responses (CR) and 14 partial responses (PR) were achieved with EPI treatment alone for an overall response rate of 50%. The median duration of response was 6.5 months. Among the 25 patients treated with EPI+LND, 5 PR (21% of 24 evaluable patients) were observed with a median duration of response of 7 months. The median survival in patients receiving both treatments was 20 months. The survival for all patients was 18 months. The survival of patients receiving LND was not significantly longer than for the other patients. Myelotoxicity was the most common side-effect followed by alopecia, nausea and vomiting, and stomatitis. LND-related toxic effects were mild-to-moderate epigastralgia and myalgia. Anthracycline-related toxicity was the same in the two treatment groups. This study indicates that LND may circumvent clinical resistance to EPI without altering the pattern or severity of the toxicity of this anthracycline. Continued investigation of the clinical modulation of EPI resistance by LND in breast cancer is warranted, hopefully in patients with known multidrug resistance status.

Biochemotherapy with thymosin alpha 1, interleukin-2 and dacarbazine in patients with metastatic melanoma: clinical and immunological effects

BACKGROUND

DTIC and interleukin-2 (IL-2), as single agents, have a limited anti-tumor activity in patients with metastatic melanoma. Experimentally, thymosin alpha 1 (TA1) may modulate the action of IL-2. We investigated the clinical and immunological effects of a combination with these three agents.

PATIENTS AND METHODS

Forty-six patients with measurable metastatic melanoma were treated with DTIC 850 mg IV on day 1, TA1 2 mg s.c. on days 4 to 7, and IL-2 18 MU/m2/d by continuous intravenous infusion on days 8 to 12. Cycles were repeated every 3 weeks.

RESULTS

Objective responses were obtained in 15 (36%) of 42 evaluable patients (CI at 95%: 22%-50%). Two patients experienced complete responses, and stable disease was observed in five. The median time to progression was 5.5 months and median survival was 11 months. Side effects were predominantly caused by IL-2. Treatment was tolerated reasonably well, and there was no overlapping toxicity or interference between chemotherapy and biotherapy. Baseline sCD4 levels seem to correlate to tumor burden. Patients benefiting from treatment had lower sCD4 and higher sCD8 than did progressing patients.

CONCLUSIONS

The combination of DTIC + TA1 + IL-2 is active in the treatment of advanced melanoma, with acceptable toxicity. However, even more active regimens are needed, and the interactions between thymic hormones and cytokines should be further explored.

Combined treatment with buserelin and cyproterone acetate in metastatic male breast cancer

BACKGROUND

Male breast cancer (MBC) is considered an androgen-dependent tumor, and as in prostatic cancer, responses have been reported with use of antiandrogens or gonadotropin-releasing hormone analogs. Thus, it is reasonable to postulate that better results could be achieved by combining these two agents.

METHODS

Eleven men with recurrent or progressive carcinoma of the breast have been treated with buserelin 1500 micrograms subcutaneously daily in the first week and 600 micrograms daily subsequently and cyproterone acetate (CPA) 100 mg twice a day orally starting 24 hours before the first dose of buserelin.

RESULTS

Objective responses have been observed in seven patients with a median duration of 11.5 months (range, 9-24+ months). Responses were not correlated to the dominant site of disease. Three patients had stable disease lasting 5 months. Median survival was 18.5 months. Side effects primarily were decrease or loss of libido, impotence, and hot flushes.

CONCLUSIONS

Total androgen blockade with buserelin and CPA seems effective in the treatment of patients with advanced cancer of the male breast, but its superiority over standard androgen suppression remains to be demonstrated.