Phase I Trials of Molecularly Targeted Agents: Should We Pay More Attention to Late Toxicities?

Creatinine clearance is associated with toxicity from molecularly targeted agents in phase I trials

Objectives

This study aimed to evaluate any correlations between baseline creatinine clearance and the development of grade 3/4 toxicities during treatment within oncology phase I trials of molecularly targeted agents where entry criteria mandate a serum creatinine of ≤1.5 × the upper limit of normal.

Methods

Documented toxicity and creatinine clearance (calculated by the Cockcroft-Gault formula) from all patients treated with molecularly targeted agents in the context of phase I trials within our centre over a 5-year period were analyzed.

Results

Data from 722 patients were analyzed; 116 (16%) developed at least one episode of grade 3/4 toxicity. Patients who developed a late-onset (>1 cycle) grade 3/4 toxicity had a lower creatinine clearance than those who did not (82.69 ml/min vs. 98.97 ml/min; p = < 0.001).

Conclusion

Creatinine clearance (even when within normal limits) should be studied as a potential factor influencing late toxicities in the clinical trials of molecularly targeted anti-cancer drugs.

Defining the risk of toxicity in phase I oncology trials of novel molecularly targeted agents: a single centre experience

BACKGROUND

This study defined the risk of serious toxicity in phase I trials of molecularly targeted agents (MTA).

PATIENTS AND METHODS

A retrospective analysis of toxicity data from patients treated in phase I trials of MTAs was carried out to define the rate of treatment-related grade 3/4 toxic effects, deaths and risk factors associated with grade 3 or more toxicity.

RESULTS

Data from 687 patients [median age, 59.1 years (range 12.5-85.5)] treated in 36 trials were analysed. Two hundred and eleven patients were of Eastern Cooperative Oncology Group performance status (PS) zero, 432 of PS one, 38 of PS two and 6 unknown. The rate of grade 3 and 4 events was 14.1% (n=97) and 1.9% (n=13), respectively. Twenty-four percent of events were gastrointestinal, 22% constitutional and 20% metabolic. PS two was associated with a higher risk of toxicity [odds ratio (OR), 2.6; 95% confidence interval (CI) 1.1-6.1; P=0.032] as was receiving >100% of maximum tolerated dose or maximum administered dose (OR 2.5; CI 1.6-3.9; P<0.001). Mortality rate was 0.43% (n=3).

CONCLUSIONS

Therapy with novel MTAs in phase I trials is associated with a moderate risk of significant toxicity. This appears less than in phase I studies involving cytotoxic agents, particularly in relation to grade 4 toxicity. The risk of death is low.

Phase I study of saracatinib (AZD0530) in combination with paclitaxel and/or carboplatin in patients with solid tumours

Background:

As a prelude to combination studies aimed at resistance reversal, this dose-escalation/dose-expansion study investigated the selective Src kinase inhibitor saracatinib (AZD0530) in combination with carboplatin and/or paclitaxel.

Methods:

Patients with advanced solid tumours received saracatinib once-daily oral tablets in combination with either carboplatin AUC 5 every 3 weeks (q3w), paclitaxel 175 mg m⁻² q3w, paclitaxel 80 mg m⁻² every 1 week (q1w), or carboplatin AUC 5 plus paclitaxel 175 mg m⁻² q3w. The primary endpoint was safety/tolerability.

Results:

A total of 116 patients received saracatinib 125 (N=20), 175 (N=44), 225 (N=40), 250 (N=9), or 300 mg (N=3). There were no clear dose-related trends within each chemotherapy regimen group in number or severity of adverse events (AEs). However, combining all groups, the occurrence of grade ⩾3 asthenic AEs (all causality) was dose-related (125 mg, 10% 175 mg, 20% ⩾225 mg, 33%), and grade ⩾3 neutropenia occurred more commonly at doses ⩾225 mg. There was no evidence that saracatinib affected exposure to carboplatin or paclitaxel, or vice versa. Objective responses were seen in 5 out of 44 patients (11%) receiving carboplatin plus paclitaxel q3w, and 5 out of 24 (21%) receiving paclitaxel q1w.

Conclusion:

Saracatinib doses up to 175 mg with paclitaxel with/without carboplatin showed acceptable toxicity in most patients, and are suitable for further trials.

Vemurafenib (PLX4032): An Orally Available Inhibitor of Mutated BRAF for the Treatment of Metastatic Melanoma

Objective:

To summarize the preclinical and clinical data on vemurafenib, approved by the Food and Drug Administration (FDA) on August 17, 2011, and discuss the drug's clinical advantages and limitations.

Data Sources:

An English-language literature search of MEDLINE/PubMed (1966-August 2011), using the terms PLX4032, RG7204, R05185426, vemurafenib, and metastatic melanoma, was conducted. In addition, information and data were obtained from meeting abstracts, clinical trial registries, and news releases from the FDA.

Study Selection and Data Extraction:

All relevant published articles and abstracts on vemurafenib were included. Clinical trial registries and meeting abstracts were used to obtain information regarding ongoing trials. All peer-reviewed articles containing information regarding the clinical safety and efficacy of vemurafenib were evaluated for inclusion.

Data Synthesis:

Before the recent approval (March 2011) of ipilimumab, there was no first-line standard-of-care therapy, with proven overall survival benefit, for the treatment of malignant metastatic melanoma. Unlike ipilimumab, which acts through immune-modulation, vemurafenib is a novel, molecularly targeted therapeutic with preferential efficacy toward a specific mutated oncogenic BRAF-signaling mediator. In recently published results of a Phase 3 clinical trial comparing dacarbazine with vemurafenib, vemurafenib prolonged progression-free and overall survival, with confirmed objective response rate of 48% (95% CI 42 to 55) versus 5% (95% CI 3 to 9) for patients who received dacarbazine (p < 0,001)

Conclusions:

Vemurafenib offers a novel, first-line, personalized therapy for patients who have mutated BRAF, Clinical trials of vemurafenib in combination with ipilimumab or other targeted or cytotoxic chemotherapeutic agents may provide more effective regimens with long-term clinical benefit.