Biotech Spectrum Pharmaceuticals (NASDAQ:SPPI) received a gift of the most precious commodity in the world this week -- time. The U.S. Patent and Trademark Office granted a five-year extension for patent protection for Folotyn, a drug added to Spectrum's lineup with its acquisition of Allos Therapeutics earlier this year.

What it means
More years of exclusivity for any product makes for welcome news in the eyes of the owner. Spectrum's Chairman and CEO, Dr. Rajesh Shrotriya, wasted no time in pointing out the potential for the extra five years to contribute to revenue growth.

The main question, though, is how much additional revenue will five more years of patent protection for Folotyn kick in? If we use 2011 sales levels, the extra time would translate to around $50 million annually, or $250 million over the five-year period.

However, the number of units sold for Folotyn fell by 10% in the first six months of 2012 compared to last year. This loss was partially mitigated by increased selling prices, but the decline raises concerns about the strength of future sales.

Whatever sales Folotyn does achieve won't include any from Europe. The European Commission rejected approval of the drug earlier this year.

Looking ahead
Alternative treatments abound for peripheral T-cell lymphoma, the rare disease targeted by Folotyn. Two generic drugs are available: Baxter (NYSE:BAX) makes Cytoxan, and Teva Pharmaceuticals (NYSE:TEVA) markets Vincristine. Celgene (NASDAQ:CELG) competes in the PTCL market with Istodax.

Another product in Spectrum's pipeline could threaten Folotyn sales down the road.  Belinostat also targets PTCL. The drug is currently in phase 2 clinical trials. Spectrum's partner, Topotarget A/S, recently announced positive results from the trial, although the company's news release appears to have jumped the gun somewhat.

Even with these caveats, the patent decision represents good news. While the bigger bucks will continue to stem from colorectal cancer drug Fusilev, Folotyn's contributions to the bottom line are significant and should remain so for the next several years. 

Five more years helps. As they say, time is money.

Fool contributor Keith Speights has no positions in the stocks mentioned above. The Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.