Since releasing its fourth-quarter results on Feb. 5, Allergan's (NYSE: AGN) share price is up 9.6%. This comfortably beats the S&P 500's return over the same time period, with the wider index being up 5.3%.

So what's the reason for the strong show from Allergan in recent weeks? More importantly, though, can it maintain its strong showing of late throughout the rest of the year?

Strong growth prospects
The fourth-quarter results showed that Allergan had a challenging quarter, with earnings per share being $0.01 lower than they were in the fourth quarter of 2013. Despite this, it was a strong year for the company, with EPS increasing by just under 17% and being forecast to increase at a faster rate over the next two years.

EPS are forecast to grow by over 28% in 2014 and by 13.3% in 2015, thereby giving an annualized forecast EPS growth rate of over 20% over the next two years. This is highly impressive and is significantly higher than the average for the S&P 500, where mid-single-digit EPS growth remains the norm.

Sector comparisons
When compared with Pharmaceutical sector peers, such as Johnson & Johnson (JNJ 3.69%) and AbbVie (ABBV 3.59%), the impressive nature of Allergan's EPS forecasts is evident. Indeed, Johnson & Johnson is forecast to deliver EPS growth of 21% in 2014 and 7.9% in 2015, which works out as an annualized growth rate of just over 14% over the next two years.

AbbVie, meanwhile, is forecast to deliver EPS growth of just under 22% in 2014 and just over 14% in 2015. This works out as an annualized rate of just under 18% over the next two years, comparing favorably with Johnson & Johnson's 14% but being behind Allergan's 20% per annum.

Strong news flow
Part of the key to Allergan's above-average growth rate is positive news flow regarding the potential for its products. For instance, during the fourth quarter of 2013, Allergan received approval from the FDA to market Juvéderm Voluma, the first and only filler approved to temporarily correct age-related volume loss in the cheek area in adults over age 21.

Furthermore, Vistabel received a positive opinion from the Agence Nationale de Securite du Medicament et des Produits de Sante for the temporary improvement in the appearance of moderate to severe canthal lines (crow's feet lines), either alone or at the same time as glabellar (frown) lines. Allergan now has licenses in 19 countries in the European Union, which bodes well for future sales growth of the product.

Don't overlook the rivals
Of course, Johnson & Johnson and AbbVie also have their own positive news flow regarding the potential of their products. For instance, Johnson & Johnson has had success with FDA approvals for ibrutinib (lymphoma) and simeprevir (hepatitis C), while the company is also seeking to grow its non-pharmaceuticals capability and has raised capital already in 2014 through the sale of its blood testing unit to Carlyle Group for just over $4 billion.

Meanwhile, AbbVie announced the completion of its Phase 3 hepatitis C virus studies on the day of its fourth-quarter results release. The news was positive, with patients enrolled in the trials sustaining relatively high responses to treatments. Furthermore, AbbVie announced during the fourth quarter of 2013 the initiation of two further phase 3 trials, which highlights the potential the company has in its mid and late-stage pipeline assets,

Looking ahead
So while all three companies have strong growth potential and encouraging news flow regarding their pipelines and product developments, the higher forecast growth rate of Allergan could be the reason it has beaten the index (as well as Johnson & Johnson and AbbVie -- by 13% and 10%, respectively) so far in 2014. Indeed, Allergan looks well placed to continue to experience a strong 2014 and could stay ahead of the S&P 500 through the rest of the year.